73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Projects Posts (NOT VEHICLES) => Topic started by: SUX2BU99 on July 10, 2008, 01:43:01 pm
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Here's some pics of my in-progress swap. So far it's just been prepping the 'new' diff for installation into my truck. Here are pics and descriptions as taken from my cardomain.com page.
This is a page showing the new 12 bolt rear end that I have bought for it. It came from another 81 shortbox and to my very pleasant surprise, it is a 3.40 factory posi! I was looking for a 3.42 posi and all I know about this was it was $150, out of the truck and would fit my truck. Guy said it was a 10 bolt. Nope, turned out to be a 12 bolt and when I took the cover off, I couldn't believe it was the ratio I wanted AND a factory Gov-lok limited slip! The guy selling couldn't believe it either and said if he knew it was a posi, it would have been double the price. Score! http://www.cardomain.com/ride/3001366/2
This is it after I got it home. Sat outside for a year so covered in surface rust and some oil spots. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_11_full.jpg)
The one drum came off fine. This one was STUCK on. The brake was totally engaged and there was no slot to back the adjuster off. I had to hammer it off with a ball peen and a crowbar from the back side a little at a time. It sucked, but it finally came off. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_3_full.jpg)
(http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_7_full.jpg)
This is the diff in my truck now. 12 bolt with 2.76 open carrier. Doesn't work all that great with my new cam and heads so out it goes. I'll be swapping over the brake lines and the chrome cover I just had put on it in May 08. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_14_full.jpg)
I had a lot of trouble getting the lines off. One bleeder busted off, the other one came off with repeated short tugs on the socket wrench. Both brake lines wouldn't budge even with a flare nut wrench. I had to cut the lines off at the nut and then use a socket. Penetrating oil didn't seem to do squat. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_6_full.jpg)
I used a wire wheel in my drill and went over the whole thing to remove as much surface rust as I could. It removed quite a bit. The cover and drums I did not do as I won't be reusing them. I then sprayed it down with Simple Green and washed it off, then blow-dried with my ShopVac and let it air dry overnight. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_15_full.jpg)
This is how I move this thing around, since I have to get my wife's Tahoe back in the garage at night. It's ghetto, but it works. Make no mistake, these diffs are HEAVY. For sure over 200 lbs (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_16_full.jpg)
And here it is with Chassis Saver gloss black paint. This stuff is awesome! When dried it's very hard and feels like thick powdercoat. I put 2 coats on. Very little of this goes a long way. I bought a 1 qt can because I thought I would need that much. I bet the tiny 4 oz. can would have done the truck. Use gloves though!! I didn't have to do the drums and cover, but did anyway since I had so much left over in the little tin I poured some in to in order to paint it. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_17_full.jpg)
Another view (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_18_full.jpg)
Here you can see the texture difference. The axle tubes I have wire brushed. The cover I have not. The paint is nice and glossy but it develops bubbles and such underneath it so it's not show-car perfect but it will look good and new under my truck. Now it awaits removal of the brakes to get the parking brake cable off, and then installation in my truck. (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_19_full.jpg)
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Cool! bet you cant wait to get her in ;D
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looks good! drop those drums off and put on some discs!
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Looks good, I second the disc brake upgrade..
Interesting way of moving the diff around, it works I suppose..just easier to carry them if you don't have far to go, IMO..
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Where did you get the Chassis Saver gloss black paint did you get it from eastwood ?
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^ Thankfully a local hot rod shop carries it. They carry POR15 too after everybody asked him to stock it, but nobody buys it lol They buy the CS stuff though.
Nah, no discs right now. I'm challenged enough trying to find DETAILED info on the 'net about removing the drum brake assemblies, let alone swapping to discs.
Carry the diff? Well maybe if one end was on the creeper but there's no way I'm going to try and Hercules that thing around myself lol It's heavy and awkward.
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Update: stripped down the pass side brake assembly, and took lots of detailed pics. Bought new Raybestos shoes, springs and wheel cylinders. $99 w/ tax, along with the brake spring pliers and hold-down spring tool ($17 w/ tax). Wire-brushed the backing plate and painted it with CS, along with the other hard parts that did not come with the new kit.
Throughout the week I hope to have the pass side reassembled, drivers side stripped down, cleaned, painted and reassembled. Over the weekend I would love to have the diff in my truck removed and who knows, maybe even the new one installed. Lofty goal though.
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Later this summer after I do a motor swap I plan on adding rear discs on both my 2 & 4 wd trucks.
http://www.blackbirdscustomtrucks.com/index7.html (http://www.blackbirdscustomtrucks.com/index7.html)
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Okay so made some progress with the one brake.
As original: (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_20_full.jpg)
Stripped down and wire-brushed: (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_24_full.jpg)
And reassembled with new springs, wheel cylinders and shoes and painted with chassis saver: (http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_25_full.jpg)
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Nice!
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looking good! Be sure to add a line lock to your front brakes so that you dont mess those new shoes up when you do some burn outs!
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^ No doubt. At the drags last Friday I saw a guy whose line lock didn't unlock on him fully and he smoked the drivers front tire all the way down the track.
Tonight I got the drivers side brake tore down, wire brushed, and all parts repainted. Reassembly tomorrow :) And then it's prep time for the swap. Woohoo!
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I figured I'd run down a plan of attack on how I'm going to remove my diff in the truck. If anything looks wrong, please let me know:
- raise truck with tires off the ground and support it. Remove wheels, drums and disassemble brakes so parking cable can be removed. Reassemble brakes, and put drums and tires back on
- remove brake lines from diff at the distribution block that bolts onto the diff housing since I believe this is connected to the rest of the truck with a rubber hose that cannot be removed without cutting it
- unbolt u-joints from driveshaft and diff. I think this is just as easy as undoing bolts right? Anything special to know here?
- lower truck enough so weight is taken off of suspension but tires still touching ground. Support with jackstands at frame rails, loosen and remove u-bolt nuts and u-bolts
- raise truck so that diff can become clear of contact points with leaf springs. This will have to be done one side at a time since all I have is a floor jack
- roll diff out of the way
How does that sound?
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Looks like you got it covered.
You can remove the hose from the truck but you have to remove it from the hardline.
u-joints= nothing special
If you are taking your tires off you won't be lowering it with them still touching the ground....
I put the jack at the center of the pumpkin and lower it all together. You should be able to balance it from one side.
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The u-bolts for the axle will be a lot easier to remove when the tires are out of the way. You are going to want to clean the theads with a wire brush and spray some pb blaster on them and use a long cheater pipe to break the nuts loose.
Support the diff with the jack and the wheels removed, not using the ground with the wheels on.
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Alright, well that's 2 experienced votes there to not put the wheels back on, and use the jack instead to take weight off the suspension. Will it be stable enough on the jack when it's ready to be pulled away from the truck?
Maybe I will look for a different brand of penetrating liquid. Liquid Wrench didn't seem to do anything for my brake lines!
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For penetrating fluid, PB Blaster is tough to beat. WD40 works well, but seems it takes longer to get the same effect.
As for removing the diff, I would think wheels off is the best way to go, less weight to sling around. It should balance fairly well in the center, most of the weight resides in the housing. As for raising the truck one side at a time - use your noggin and save some time. A stout 4x4 or 4x6 timber can be used as a bridge between the frame rails out near the bumper. Just balance it on the jack, center the jack between the rails, and lift away. Don't get under it until it's safely on stands, but that goes without saying.
Smitty
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That is some nice work on that axle! Want to come and do mine? ;D
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:D After the amount of work it's been so far, I don't think I'd want to be doing this again anytime soon! But I'm learning new stuff so it's been okay so far. Some of the bumps along the way have kinda sucked but at least it hasn't stopped me.
Update: started on the swap tonight. I'm not exactly doing it in the order I laid out earlier. Here's what I've done so far:
- raised truck as high as the floor jack would go and supported truck on jackstands at frame rails
- sprayed off flare nuts, shock bolts and u-bolt nuts with brake cleaner, then wire-brushed, then sprayed on some Liquid Wrench
- took off wheels and drums
- backed off flare nuts a bit just to know they will move, which they did. Tried doing it at the distro block too and one came loose. The other is starting to round over >:( But, I can take the hard lines off the diff and let them stay on the truck while doing the swap. It's not necessary to remove them from the truck.
- broke the nuts on the shock bolts free and loosened them
- used floor jack to take some weight off the suspension
- tried loosening the u-bolt nuts. No such luck. What I have right now for a breaker bar is a tire wrench that accepts a 1/2" socket head, but it's bent at about a 60 degree angle, not 90 degrees so when I pull on a nut, I'm not getting full torque. It's skewed and makes the socket pull at an angle. It worked for the shock bolt nuts but I'm going to have to get a real breaker bar for the u-bolt nuts. That's too bad cuz the tire wrench is about 30" long but I don't like how it pulls on the deep sockets, plus it wasn't breaking them loose
- forgot about the shackle bolts. So I hosed them and the u-bolt nuts down again with Liquid Wrench and will go at them another day.
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I have an old trusty 24" snapon 1/2" ratchet. I used that. You could use a torque wrench, they have a good long handle and your going to need one to put it all back together correctly anyway. Just break them free and you can rattle them off with your air wrench.
Go out and get the right tools with the money you are saving by doing this yourself. ;)
Just keep one eye on the the jack stands and your ears open for creaking sounds. Those u-bolts are tight and you can pull your truck off the stands. :o
I only use 6ton stands and as you put weight on them take the time to give each leg of the stand a gentle whack, it keeps the legs square on the floor. Oh, and chock the front wheels.
Good luck and be safe.
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Good advice. I find it's difficult finding 1/2" breaker bars longer than say 18", and if they are they want $50 or more for them. I never really thought about a torque wrench since I figured they would be sensitive or something. I guess that doesn't make any sense considering their use.
I felt the truck move back somewhat after I had put it on jackstands and was lowering the pumpkin. I'll do that trick of tapping the stands to be safe.
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I picked up a 24" 1/2" breaker bar at Princess Auto for $15 yesterday and took that bad boy to the u-bolt nuts. They all cracked loose so that's great. Now I just have to get at the u-joint bolts, take apart the brakes to remove the parking brake cable and the swap is a go.
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woo hoo!
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wish i had those 2.76 gears myself
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If shipping wouldn't be way too much, we could work out a deal!
Took the brakes apart just enough to get the parking brake cables off and reassembled them. Took the brake lines off the diff, loosened the u-joint bolts, took 1 u-bolt nut off to get some replacements but no such luck yet. My impact gun is such a wimp! Used my breaker bar to get it off the whole way which was a slow process since it isn't a ratchet.
Bought a 1/2" torque wrench yesterday which will speed up removel of u-bolt nuts plus ensure I'm putting everything back together correctly. Only have the vent tube bracket bolt to remove and everything can come apart.
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Question: when I got to put the new diff back in, do I connect the shocks up first and then use the floor jack to compress them and then get the u-bolts on? Or do I put the u-bolts on first? Reason I ask is the shocks are in compression a little bit even then the springs are hanging all the way down. When I unbolted the shocks, they extended out a inch or so and I will have to compress them in order to get them back on, right?
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Easier in my opinion to bolt the axle in and then do shocks for the simple reason that shocks will twist the axle on you. Just make sure to tap the u-bolts inward once in a while to keep them square. Otherwise they might appear tight and move later. Extra 5 minutes now cheaper than a drieveshaft when the axle rotates while driving.
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Scottsdale is right on the money
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ALWAYS re-torque U-bolts after driving
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Good advice guys. I would rather bolt the diff in first anyway and do the shocks 2nd. The old shock bolts are still in the new diff because they wouldn't budge so I want it anchored before I got at them with the breaker bar to get them out.
So once the diff is bolted in, what's the best way to compress the shocks?
Finally, is it wise to use thread lube/anti-seize on the u-bolts or any nuts/bolts that have to get torqued?
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Update: got the darn thing out! Man, those u-bolt nuts were TIGHT! And my impact gun is such a wimp. Took a while turning them 1/3 turn at time with the breaker bar or ratchet to get them loose.
I had the floor jack underneath ready to catch the diff when it came away from the leafs but that didn't happen as gracefully as I hoped. The diff was stuck to the leafs so I had to use a crowbar and a hammer to get them apart but when the last side came apart, if fell onto the floor jack, then fell forward and flipped over on the floor. Took a chunk of concrete out of my floor too! Oh well, it's out now anyway.
Is the diff supposed to be able to reasonbly balance itself on a floor jack? It sure doesn't seemt to want to. The snout keeps tipping it over. Because of this I'm not looking forward too much to getting the new diff positioned by myself.
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It'll go right up in there. Get one side into position on the pin and use another jack or stand to keep it in place then jack it up more to get the other side in.
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Good plan. I can manage that. I have a tube of Permatex thread sealant that I've been using on the brake hardware to prevent frozen fittings later on. Can I use this too on the u-bolts and shock bolts?
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Thread Sealant? No Don't put anything on them
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Cool. I thought I read something on the tube about not using on nuts that are critical to be torqued. The 'sealant' I think is more of a lube to prevent corrosion. Kinda like an anti-thread lock.
I did a search on here as I'm sure it was discussed before but I couldn't really find the answer I was looking for: what's the oil capacity of a 12 bolt? I have the number of 1.8L floating around in my head. Almost 2 bottles, but not quite. I'll be filling the new diff outside the truck with the snout pointing down (since it's easier that way), so I won't be filling it in the truck up to the point where it's level with the drain plug (the suggested method I found in another thread).
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It should be 2.45 quarts.
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Ohhhh, well I'm glad I asked then. That's more like 2.5 bottles. Thanks!
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Chris, not trying to 2nd guess you but is that quantity for a 12 bolt? I looked it up on the autozone site and they say 1 3/4 quarts, which is at the 1.8L (1 L = 1 quart) number I had in my head. I know when I had my oil changed in May, I bought 2 bottles and told the mechanic it takes 1.8L. That number came from somewhere, but I just can't remember.
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Why not just fill it when you get it in the truck the normal way?
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Your right, I think it is almost 2 quarts from empty.
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Since I had both diffs sitting in my garage wtih the snouts hanging down, it was easy for me to swap covers and fill the new diff with oil, of which I did. I put in 2 quarts of Castrol 80W-90 Hypoy C oil along with a bottle of GM friction modifier for posi diffs.
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Does anybody have the torque values for the following:
- u-bolt nuts
- u-joint nuts
- shock bolts
- diff cover bolts
Thanks!
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These values are best read from a good book. I am sure no one here would deliberately steer you wrong, however it is a good habit to get into to verify something as important and easy to look up as torque values.
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I refer to this (http://www.chuckschevytruckpages.com/chevy_front_suspension_torque_specs.html) page alot, for stuff like that. Can't vouch for the accuracy of the info though. Check the bottom of the page.
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^ Wow, cool site! Definitely one to bookmark and go through. Thanks for that, and yes I should just buy at least a Haynes manual for stuff like this.
CCZ, when you swapped your axle, what was your method of getting the shocks back on to their mount? They have to be compressed I know. I was under there last night cleaning the area up in prep for the new axle which should be going in tonight I hope ;D and I tried compressing the shock myself but it didn't want to seem to budge. Should I use the floor jack to compress it enough to get onto the shock mount?
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CCZ, when you swapped your axle, what was your method of getting the shocks back on to their mount? They have to be compressed I know. I was under there last night cleaning the area up in prep for the new axle which should be going in tonight I hope and I tried compressing the shock myself but it didn't want to seem to budge. Should I use the floor jack to compress it enough to get onto the shock mount?
I just pushed... steady push, it finally started compressing. once it starts moving, you got it. have your bolt ready before you start and compress it more than needed, it takes two hands, then when it expands, guide it towards the mount and throw the bolt in. I had to do this more than once to get the hang of it.
Couldn't have done more than one truck, though. Need to eat your Wheaties :D
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lol Just muscle it in eh? Alright, I'll give it a whirl. Thanks.
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You should be able to compress it with your hands as CCZ said. Once you overcome the initial "umph". Technically you shouldn't leave them extended though...
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Right on. I didn't give it too hard of a try last night but I will be tonight or tomorrow. They've been fully extended for less than a week so hopefully that hasn't damaged them. My time is on the short side of supply!
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DONE!!
I gotta say that putting it in was a TON easier than getting it out! I rushed to get it all together by Friday afternoon to take it to the Friday night street legal drags at Mission Raceway. I got very close to getting it done in time but not 100% :-\ Oh well, in 2 weeks there is another race. I did get it driveable though. Everything went in well except for:
- pass side parking brake cable attachment at the drum. I was getting frustrated trying to get it clipped in, it was hot out and I had been hard at it for about 7 hours getting the diff in so I tie strapped it to the frame and will get to it later. I got the drivers side done though
- had to put the non-turned drums on since my freshly turned drums would not fit onto the shoes. I would have to force them and they'd drag a lot even if they did go on. I can't figure out why 1 pair of drums is a smidge smaller than the other. I backed the brakes off and I did drive it like that. No funny noises or vibrations though but I will get those drums turned.
- the new diff's shock mount bolts were rusted on their super tight. One bolt broke so that was okay, but the other would NOT go anywhere. The bolt head started to turn inside the socket. So I had to cut it off at the nut and my new, never-used air body saw wasn't working well and eventually quit, so I had to use a hack saw and broke 3 blades. I got it off though so whatever.
- the new grade 8 bolts I got for the shocks were too big I found out when trying to put them so had to do a parts store run and get smaller bolts
- I bought new u-bolts and hardware and the day I was supposed to pick them up, they forgot to leave them outside for me, so I had to wait another day for them
Otherwise it went well :) Torqued everything up. I drove it Friday and today and it's running great. The 3.40 gears are a nice improvement over the 2.76's for getting the motor into it's powerband. Now when I stomp on it from idle or a 1000 rpm roll, it seems the converter will flash to 2500 and then go. Before it might flash at 1800 or so it seemed. Bad news it seems the posi isn't all that tight :( Good news it will pretty much light up at least 1 tire from an idle stomp, if the carb doesn't stumble so bad that it stalls. I even had it light 1 tire and some of the other and then spin and hold it right into 2nd gear. If it brake-torque it anywhere past 1500 both tires start to spin. I'll have to work on getting my launch right.
So it's been about 2 months since I bought that very rusty diff from a bone yard for $150 but it's now all painted and in, with new brakes and u-bolts and I have 1 more project under my belt.
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Here are some pics. I have descriptions and more pics listed on my page http://www.cardomain.com/ride/3001366/2
About to come out
(http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_36_full.jpg?)
Old diff out
(http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_39_full.jpg?)
New diff guts showing limited slip unit
(http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_40_full.jpg?)
New diff in
(http://memimage.cardomain.com/member_images/1/web/3001000-3001999/3001366_44_full.jpg?)
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good job man
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Ahhhhhh, pics...
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looking good ;D
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Just so you know, the gov lock isn't really meant for on road lockups , if you abuse it even slightly it will come apart. There is a reason they Call em the Timex posi...cause its a time bomb waiting to explode.
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Since I wrote this, I've taken that diff out and just put in another 3.40 Gov-lok. This unit apparently works fine though. The last one did not and I went through a whole schmozzle of new Eaton Posi, 3.73 gears, multiple failures, blah blah blah. Anyway, the old Gov-lok was seized and unworking. It went through about 20-30 dragstrip passes and burnouts with no issues at all but it wasn't working right anyway. I am a little worried about blowing this 'new' one up but I've heard of the good ways to blow up Gov-loks and I won't be doing that (like right-turn throttle stomps or one tire spinning on gravel and then hitting pavement where it grips suddenly).
My truck doesn't seem to like burning the tires off from an idle so it might just be fine.
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not to mention this post is like 1.5 years old..
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Just bringing it up for everyone elses info.
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There is a reason they Call em the Timex posi...cause its a time bomb waiting to explode.
Doesn't Timex take a lickin and keep on tickin?
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I grenaded the pozi in my 12 bolt to..rebuilt the rear end then sold the engine out of the truck..lol if you need another i have one sitting here..thought it is 6 lug.
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There is a reason they Call em the Timex posi...cause its a time bomb waiting to explode.
Doesn't Timex take a lickin and keep on tickin?
Apparently not...
(http://ctaxleservice.com/images/GMgovloc-exploded.jpg)
(http://ctaxleservice.com/images/GMgovloc-spider.jpg)
One of the drawbacks is the gov loc limited slip carrier that GM used. This unit uses a series of small spinning shafts that fling out a camed sprag to engage teeth on the end of the shaft to make both wheels turn. The problem is that once you start spinning the wheels and these parts engage at a high rate of speed, the shafts tend to break and take out the rest of the gears.
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Nice watch!