73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: liftedchevys87 on June 08, 2010, 05:31:29 PM
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1987 Chevy V10 4x4 (1/2 ton, 350ci, 700r4 tranny)
I have a Chevy with a 6 inch lift and 37 in tires. It has stock axles with 3:46, I checked the G code for the rear end ratio I know it's around 3:40.
I want to change the gear ratio to somewhere in the mid 4:00's to compensate for the big tires so It don't lug so bad and it runs the proper rpm on the highway. I didn't want to swap the hole axles so my question is....how hard and realistic is it to just change the ring and pinion gears. Anyone know of any problems to look out for? Just wondering about people's experience with axles. Thanks
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I'll be following you here. I need to change the gears in my red truck. I have swapped the axles in my truck do to the rear self destructing and a gear swap has got to be easier in my opinion, unless you have a shop with a lift.
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Unless you are experienced at it don't attempt to do it yourself unless you are prepared to use it as a learning experience. It's really not a DIY job unless you're equipped with the means. If you search you'll see several threads on this subject. If you do decide to take it on yourself I'm happy to help with your questions. 4.11:1 should get you where you want to be and your stock ratio is most likely a 3.42:1
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Yeah, 3:42 is what it is. Yeah I've never done it before but I gotta learn some day so I'll go after it myself lol. Thanks
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You're in CT too so if you need help I'm not too far
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have to say I'm with vile again on this, not a diy job unless you want to have someone do it again for you. I've done ping and pinions well just rings on a 14 bolt (changed lockers out) not hard but you don't deal with shims just two nuts you unwind or wind up till it all matches up
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Thanks Vile
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Yes, bringing it up again...Directed to Irish and Vile... 14 Bolt Full float in my 1985 C30. I am wanting to do a gear change. To hear Irish say it isn't bad at all. Vile what do you think? I just picked up a series 3 Gov-loc for 4.10 and below. My truck has, or it is suppose to have a 4.56 according to the code on the sticker in the glove box. Still trying to find the right deal on 3.42 gears so I have time. I wish the aftermarket had the stock 3.21 like my C20 has in it now. I am going to see if there are any YouTube how too's as well later this evening. Thanks in advance guys.
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Once again to state that vile knows what he is talking about. You need the right tools, the guessing game gets frustrating to say the least. The best thing to do for your first time is pay someone to show you and teach you. It is not impossible to do, the first set I ever did, well lets just say they did not last all that long, then I got smart and had someone teach me.
You-tube does have some great tutorials on setting ring and pinions.
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Once again to state that vile knows what he is talking about. You need the right tools, the guessing game gets frustrating to say the least. The best thing to do for your first time is pay someone to show you and teach you. It is not impossible to do, the first set I ever did, well lets just say they did not last all that long, then I got smart and had someone teach me.
You-tube does have some great tutorials on setting ring and pinions.
I agree but if the 14 Bolt full float is easier because of what Irish has eluded too??? It doesn't cost anything to ask...
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I have never tore apart a 14 bolt before, hopefully they are easier. If that is the case let me know so I can put 14 bolts in my truck. ;D
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14 bolts are easier to setup backlash, because it has adjuster nuts. I don't know what a 10/12 bolt diffs have for adjustment. If they are anything like a Dana you better have a pretty good toolbox to get bearings off and on the side of the carrier.
In all reality a 14 bolt will not be much easier, its still the same steps. Setting up preload on the pinion bearings, and getting backlash and preload right on the carrier. And that doesn't even take into account of getting the pinion depth right, so the wear pattern is correct.
I know lots of guys that will rebuild a V-8, can make a carburator run, but refuse to work on differentials. I don't particularly like to do diffs, but I can. I've done JD farm tractors, Cat farm tractors, Dana 44, 60, 70, 80, and 14 bolts. It takes patience, and the ability to keep taking it apart and putting it together until its right. Its best to find someone that has done a bunch successfully to help you through the first time, and maybe watch you do the second one. Or at least check your work.
Michael
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There are a lot of shops that can't even do this right but if you're smart and determined you can do it. I say if you believe you can achieve. The adjustable collar on the carrier is nice and makes setting preload and backlash much easier than dealing with a housing spreader and aftermarket shims.
Let me ask a few ?s
Why do you want to do the swap? Do you have access to a dial indicator, pinion depth gauge, in lb dial torque wrench, hydraulic press, gear marking compound, pry bar and a means of fabricating or obtaining a pinion flange holding fixture?
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There are a lot of shops that can't even do this right but if you're smart and determined you can do it. I say if you believe you can achieve. The adjustable collar on the carrier is nice and makes setting preload and backlash much easier than dealing with a housing spreader and aftermarket shims.
Let me ask a few ?s
Why do you want to do the swap? Do you have access to a dial indicator, pinion depth gauge, in lb dial torque wrench, hydraulic press, gear marking compound, pry bar and a means of fabricating or obtaining a pinion flange holding fixture?
I just don't have anyone I know and trust to do it and have heard horror stories about local shops doing it. I am not opposed to buying the tools needed to do the job and can make most anything. I have access to a hydraulic press, and I have the in lb dial torque. Bottom line I want it done right and I have all winter to get it done as it was officially taken down to Comprehensive insurance till spring. I am on a fishing expedition for information.
I am going to check with a 4x4 shop I know of that has been in business for a long time and see what they charge.
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Hey zieg, if you end up doing it, take a lot of pics, I bet there will be people following your progress. Good luck with your search.
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After "carefully" reading the following article:
http://pirate4x4.com/tech/billavista/PR-ARB/articles/14b_Gear_Setup/
I have decided to seek out an expert. Having access to tools is not like having them yourself. Those special clam shell bearing removers are slick... I'll just have to do my homework on finding a reputable shop and hope for the best.
Thanks guys for giving me some direction and the drive to research it a little. The truck is going to be stored in its resting place this winter in the next week or two so I have about 4 months to find a shop.
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Besides the obvious of not having to crawl around on the ground, are there any other significant advantages and reasons why you should do this with the axle out of the car?
(i'm trying to determine the feasibility of doing it in car)
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cause then gravity will not be fighting you it all falls in place when its out of the truck
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So Zieg, why do you want to change gear ratio's? What made you not want to tackle this now?
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So Zieg, why do you want to change gear ratio's? What made you not want to tackle this now?
First part of the question is the 4.56 in my C30 makes it not fun to drive, at all. I want to be able to run it down the highway at the 70 mph speed limit and not be afraid of spinning a bearing because of the high rpm. I want a nice highway gear in it and if I can find a 3.21 I would be elated. Seems the aftermarket offerings only goes as high as a 3.42 which may be the way I have to go.
Second part is while I have access to a press, it is just a press and it is 47 miles away from where the truck is. I am confident I could pull it off and I will attempt it when I have my own shop in the near future with all the proper tools to do the swap including a lift. My shop will have a spray booth and alignment rack in it as well. Just need to wait until spring rolls around to break ground...
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Nice! What trans do you have?
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Nice! What trans do you have?
TH400.
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Have you considered a 700R4 or 4L80E instead?
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Have you considered a 700R4 or 4L80E instead?
Actually I have a 700R4 of unknown condition, it came in my 1986 C10 parts truck, all that I know is it went right into drive and reverse without any problems but... the TV cable was never hooked up to the late 70's 350 2bbl that was the heart of the beast. I haven't eyeballed the carb on my C30 so I don't know if it has the set up to operate the 700R4 TV cable and I am afraid the cost of everything properly set up would far exceed a ring and pinion change to pretty much accomplish the same end result, 3.32 final drive with the 700R4 versus whatever I end up with a 3.21 or 3.42 with the rear end gear change. I have read they can be made very robust but in this truck old school is fine with me. I like the ratio drops between the TH400 much better than the 700R4. This truck will only tow if the C20 is down for some reason. I have to watch my spending as I am balancing 2 trucks taking some sizable coin plus hopefully the shop build this spring.
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You defiantly need to start a shop, everyone deserves a shop of their own. ;D
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Agreed and what better way to waste money, time, oxygen and beer than in your garage? ;D
I would personally build the trans over the rear end and leave what you have. With those gears and a rebuilt 700R4 or 4L80E you can tow just fine.
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1) Suggestions on how to find a good shop that does this kind of thing?
2) Are there any calculators that determine rpm at any given speed if you know tire diameter, gear ratio etc.?
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Nevermind; Here's a good calculator:
http://www.ringpinion.com/Calculators/Calc_RPM.aspx
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Here's a good write-up on changing gears: Yes, it's harder than it looks! i'm thinking of just getting a new engine----or a new truck!
http://pirate4x4.com/tech/billavista/Gear_Setup/
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For Stewie's '87, to do things right, you'd have two gear sets to swap out and get set correctly.
You could try to find a matching set of axles from a 3/4 or 1-ton truck with a 4.10 ratio and swap them in. A 3/4 ton truck would still be 10-bolt front, but 14-bolt rear... The only drawback is that you could wind up with axles needing a new ring and pinion and bearings...
I'm not a master mechanic, but I rebuilt the 12-bolt rear end under my '74 K10. That was after I had observed/helped with rebuilding a couple of Dana 44's...
It definitely takes time to do it correctly.
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Every major city I have lived in, had a driveline shop that specialized in transmissions and rear ends. If you live near SW Iowa, I know a good shop that can probably pull a gear change off for you, the shop in mind is in my yard.
If you are going to do it in the chassis, its best to do it on a hoist or over a pit. The last thing you want to do when setting up a diff, is to get tired and impatient rolling around on a creeper. I have done it on jackstands, but would rather not to that again. It is much nicer doing them over a pit or on a hoist, or if those are available, pull the rear diff out and put it on stands in the garage to work on.
Michael