73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: tc197 on July 22, 2016, 01:49:17 pm
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Hi guys I'm new to the forum and this is my first post.
I have a 1987 GMC V2500 with an SM465 4 speed (3 speed with granny) that is leaking and I'm not sure how to go about fixing it. I've never worked on a transmission before and this is my first standard truck. I've tackled a bunch of problems up to this point (water pump, power steering pump, vacuum leaks, brakes, rotors, front and rear springs, shocks, etc...) through videos and this site but before I try this I wanted to get a few questions answered and look for some advice.
The leak is a slow drip where after a week I have a small puddle on the ground and I can't tell where it's coming from. I attached a few pictures below and one of my first questions is am I missing two bolts where this plate attached to the transmission?
Will I be dropping the transmission regardless to make any sort of repair?
Thanks for the help and let me know if there's any more information I can provide to clear anything up.
Tom
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Those missing bolts actually hold a brace to some engines. My 85 V-8 doesn't have them my V-6 in my 86 did have them.
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Those missing bolts actually hold a brace to some engines. My 85 V-8 doesn't have them my V-6 in my 86 did have them.
Ok good to know thanks!
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If your just chasing a leak and not planning a new clutch as well, you may want to degrease it and see if the leak is coming from the side PTO cover plate. It is much easier to fix if that is all it is
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Something else to look is the drain plug. Could it be loose or cross threaded?
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Id clean it really really good
Then Clean it again then I'd put some dye in it and use the ultra violet light to see where's it's actually leaking
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Thanks for all the suggestions. I was thinking it wouldnt be the PTO cover or drain plug because it seems to be dripping from a bunch of different places so I was thinking higher up. Does the PTO cover have a gasket inside that can be replaced?
For the dye and UV light, do you know if autozone or any of those places rent out the lights? Or does anyone have a suggested light to buy from amazon or something?
Thanks again for the help!
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Thanks for all the suggestions. I was thinking it wouldnt be the PTO cover or drain plug because it seems to be dripping from a bunch of different places so I was thinking higher up. Does the PTO cover have a gasket inside that can be replaced?
For the dye and UV light, do you know if autozone or any of those places rent out the lights? Or does anyone have a suggested light to buy from amazon or something?
Thanks again for the help!
The light is just a flashlight
I think I bought the dye and flashlight Ina kit at napa or somewhere
Obviously the light works better at night
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Ok cool Ill search around for the kit. Thanks!
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keep in mind when you drive it around the wind will push the fluid all over, so clean her up and fill it and see if it starts to drip before driving. then if still no drips take it for a short hard drive as to no make much wind but hard enough to spin the fluid all over
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keep in mind when you drive it around the wind will push the fluid all over, so clean her up and fill it and see if it starts to drip before driving. then if still no drips take it for a short hard drive as to no make much wind but hard enough to spin the fluid all over
Sounds like a plan. Im gonna find the kit today or tomorrow and hopefully I'll have some news this weekend. Thanks for the help.
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Start with the transmission, but the engines rear main seal could be leaking into the bell housing.
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Start with the transmission, but the engines rear main seal could be leaking into the bell housing.
I had read about that possibility but I was thinking I'd have drips further forward on the bottom of the motor too. The only other way I've convinced myself it's the transmission is from removing the fill plug and not being able to put my finger in and feel any fluid. I ordered a UV flashlight and dye online so Ill start with that in the transmission and go from there. Thanks!
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Dye and light came in but I didnt get a chance to play with them this weekend due to bad weather. Hopefully next weekend will be more promising
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Update:
I cleaned and degreased everything yesterday and added some new fluid and dye. Fired it up for 2 minutes and immediately saw where the leak was originating from. On the front of the trans where it meets up with the bell housing is where it was leaking, I believe that's the input shaft seal? I'll add a picture. It also started dripping a little later from the bottom of the bell housing but could that just be the same leak where part of it runs down the inside of the bell housing and part runs down the front of the trans?
Given where the leak is coming from it seems the next step is dropping the trans. My next two questions are:
1. What else should I do while the trans is out. (Ive had the truck for a few months so I dont know any history on when the clutch was done, flywheel, rear main, etc...)
2. Do I attempt this myself in my driveway or have a shop do it? Any thoughts on what it would cost me to take it to a shop?
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Leak
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Got a quote from a shop to drop the tranny, replace all the seals, and seal it all up for 800$. A lot higher than I expected. Should I just replace the tranny rather than drop 800$ into this one?
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800 for a OD trans plus a few more for new driveshaft/s if you go with a 4l80e you will need about 500 more for a transmission control unit or at least 300 for a
"black box"
but if you dont want to or cant drop the trans yourself i would think of an overdrive trans that will save you some gas millage
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After spending all day scouring craigslist and local places I found a clean sm465 that wasn't fully rebuilt but was gone through recently for 200$. Ill be headed to get it tomorrow and my plan now is to just swap leaky sm465 for sm465. With the leaky one out ill use it as practice to go through my first trans and then ill have a backup for down the road. Should be easy enough to drop the trans and tcase and swap the new one in but ill obviously find a way to screw it up.
Do I bother getting into the pilot bushing and throw out bearing while im swapping? Should I go even further than that and replace more?
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Throw out and pilot replacement isn't a bad idea.
One thing to make sure on is the spline and bolt pattern for both trans. This is the spline and bolt pattern to connect to transfer case. There are 3? Possible combinations for the sm465 transmissions.
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According to Novaks I should have a 32 spline in my truck now and the one Im picking up is also the 32 spline. I didnt realize there were different bolt patterns too. Ill have to look into that. Thanks
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The earlier 205 had a figure 8 sort of pattern the later 205 and 208 transfer case had a round 6 bolt pattern. 32 spline only came with the round pattern so you should be fine.
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Took me all day and night to get it but I have the new trans to swap in. So much work, so little time. Im also having a problem where a belt squeals everytime I start the truck for about 30 seconds. New PS pump and pulley, new water pump, belts are tight. Do I need to replace the belts?
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FYI...
Earlier SM465
The earlier era of the SM465 include the 1968 - 1978 transmissions. There were both 2wd and 4wd versions. Internally, they are identical to each with the exception of the transmission mainshaft. The 4wd version of this mainshaft (or "output shaft") has a 10-spline output with a 2-5/8" stickout and an accompanying 4wd adapter housing. The 2wd version has a 35-spline threaded mainshaft compatible with a driveshaft yoke, and accompanying 2wd style tailhousing.
Later SM465
The later era of the SM465 include the 1979 - 1991 transmissions. A minor internal change of the 1st gear bushing and thrust washer occurred, in addition to a change from a shorter 10-spline, 4wd output shaft to a 32-spline 4wd output shaft - coinciding with the change of bolt pattern in the New Process 205 transfer case from a figure "8" input bolt pattern to a round, six-bolt input pattern. This pattern was also found on the 208 and 241 chain-driven transfer cases.
the round 205 only came out in 85ish but def in 86. gm still used the 10 spline 465 from 79-85 till the round came out then went to 32 splines. the other 4wd k10/20s that got the 208 were 32 splines
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Well, plan is to pull the leaking sm465 and swap the new one in tomorrow. Hoping to get an early start as I don't know how long it will take me. Trucks on blocks in the front, trans is in neutral, removed the shifter.
Plan:
1. Drain trans and tcase fluid
2. Remove drive shafts
3. Disconnect any linkages/wires
3. Support trans/tcase and remove support cross member
4. Remove 1 bolt from trans to bell and get 4 more just like it, cut heads off, grind screwdriver slot in, and replace each bolt with a new headless bolt. (read this trick here on the forums)
5. Hook up jack with tranny adapter and secure to trans/tcase
6. Make sure the back of the motor/distributor is clear of the firewall and lower everything a bit.
7. Add support to back of the motor
8. Slide trans/tcase off the headless bolts until shaft clears bell housing.
9. Lower to ground and slide out from under truck.
10. Remove old sm465, reconnect new sm465 with new gasket between tcase and trans
11. Reverse process and reinstall.
Am I missing/misunderstanding anything? Thanks for all the help!
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Should be fine, I don't think you need to remove the shifter, but I think you do need to put it in gear(either L or 2nd) so the input shaft can clear the pressure plate.
And on that note, make sure you measure how much space you have under the truck, because of the bends in the shifter you need to move the tranny forward and down to get the stick out of the cab-if you can't get the stick out of the cab, it is really annoying to try and remove it after dropping it. I think I needed to put my truck on jack stands to clear the 700r4 I pulled.
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The shifter pops off easy and mines already off so i see no reason to leave it on.
Fluids have been drained
Shifter is removed
Both drive shafts removed
Disconnecting linkages and cables now
Considering pulling the tcase first and the trans after rather than both together. Any thoughts?
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i would remove it. not sure which one you have the 208 weights about 80 lbs and the 205 is 140
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Didnt see this until now. Tranny and tcase are out. Its a 208. I took them out together using a jack adapter and ratchet straps to hold them down. Im exhausted. Time to pull the old tranny off and reconnect the new one
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Looking through my throwout bearing im seeing needle bearings way back in there all out of place. Must be my pilot bearing? Guess im going deeper than the trans and that made the pilot/throwout replacement question easy. Probably gonna do the clutch while i have it out too i guess
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Bell housing is off. Clutch plates are off. Looking at the flywheel and pilot bearing finally. Now to decide what to replace while im here.
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Pulled the flywheel off and took a trip to the parts store. Picked up a new flywheel, clutch kit with throwout and pilot, fluids, and some cleaner for 200$ and rented a pilot bearing puller for free. Should have everything I need to replace the bearings, clutch, and flywheel and then just put everything else back together.
Rear main seal looked good, no leaks or marks so im not touching that for now. Ill probably be dropping a new motor in within a year or two anyways.
Ill keep you updated in the morning when I get back to it. Thanks for the help, lots of info around this site.
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Got the pilot bearing out this morning.
Put the bew pilot bearing in, mounted the new flywheel and attached the new clutch. Everything went pretty smooth considering i dont know what im doing. Cleaning off the bell housing now before I reinstall it. Families coming over for the day though so i most likely wont get any more done until tonight/tomorrow.
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Sounds like you do know what your doing- do you have a torque wrench(even borrow one) for the flywheel bolts and pressure plate? Pressure plate is probably the most important one, as you can over-tighten the pressure plate and warp it(rare but still possible)
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I do have a torque wrench. Torqued the flywheel to 60lbs and the pressure plate to 35 lbs. Found these numbers online and went with it. Used some brake cleaner on the flywheel and clutch plate before installing it too to get any oil off. Thanks for looking out!
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no problem, and those numbers sound right, it really does depend on the engine, but typically its 50-90 ft-lbs on flywheel/flexplate bolts, and 20-35 ft lbs on pressure plates. if I remember correctly my 6.5 was 70 ft-lbs flywheel, 20 ft-lbs pressure plate.
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http://www.jegs.com/tech-articles/sbc-engine-specs.html
This is where I found my numbers. Its a 5.7 350 so sounded right to me.
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Got the bell housing put back on and the trans/tcase back in. Man that sucked. Hopefully
I did it right, i didnt see anything obviously wrong so i guess ill find out in a few. All thats left are the drive shafts and new fluid. Fighting that trans and tcase as one piece on a floor jack in my unpaved driveway was tough.
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Guess what!? It was a success! New trans is in, everything shifts good from what i can tell in my driveway, the only thing is my brakes now decided not to work. Pedal is real stiff and wont brake at all until i stand on it and then it just jams the brakes. I dont think i could have screwed this up in my trans work but ill have to investigate and see what the deal is. Im relieved its brakes though and not trans related :).
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Think I found the solution to my brake issue. Since the motor was tipped way back to get the trans in and out, theres a vacuum line for the brake booster that could have been crushed. Mines super old and rusty so I cant even tell if its broken or not. After reading online as well a common cause when this vacuum line goes is the brakes become hard. Ill be replacing the line in the morning and hopijg to find nice brakig abilities again. At that point ill be able to take a ride with my new trans/clutch/bearings/flywheel etc...
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Ran new hose from the motor to booster and voila, i have brakes again. Took for a ride and everything worked great! Just as i was going to leave again i decided to check my lights out, turned the headlights on and the truck died instantly and all power waa cut off. Turned the headlights off and the power stayed cut for about 20 minutes until it randomly came back. Tried to start the truck once power came back and it idles real low and didnt want to stay running. I read online this could be a grounding issue or an issue at the little box next to the brake booster. Time to do some more research.
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sounds like a short, and the main power going to the junction(little black thing by booster) fried the fusible link(10 gauge if I remember right)
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I would say you pinched part of the harness between the bell housing and back of the block. Ditto on likely cooked fusible link. See if you can use an inspection mirror to look over the top of the bell housing. If you did pinch it....bad news...you will have to unbolt and slide the transmission back far enough to repair the damage, tie it up out of the way, and slide the trans back into place. You MIGHT not have to remove it completely, and repair it from the top instead, but you will still have to unbolt the bell housing and move it back far enough to pull the wire out.
When I installed my sm465/np205, I removed my trans tunnel and used an engine hoist through the floor to lift it in place. Little tedious by myself having to get out from under the truck to adjust the height, and once had the drop valve on the hoist creep open ever so slightly and lay the assembly on my chest, but nothing bad enough I couldn't get out from under it. Your tunnel is probably not removable, so this might not help (haven't looked at a truck with a 4 speed with a fixed tunnel, but maybe the shifter hole is big enough?)
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Shifter hole is definitely too small, it's about 6x8 oval, you could maybe fit 2 fingers down between the hole and tranny.
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Thanks for the input guys.
I would find it hard to believe I pinched a wire in the bell housing, I put that on by itself and its not very heavy or anything. I only saw two wires even hanging low enough to be pinched at all and one plugged into the top of the trans and the other was my speedo cable I think? Can't remember exactly. I definitely could have pinched something between the back of the block and the firewall because I had to lower the motor a pretty good amount to get everything out and back in. I also pinched my brake vacuum line that runs side by side with the junction so pinching a wire seems feasible to me.
How would I go about replacing/checking that fusible link? Does the junction come out? Where do these wires run to? I see the one run from the alternator, across the block, to around the junction box but then I lose it behind the motor. Classes started up today so I won't be back to the truck until Friday but hopefully I can come up with a solid plan to narrow down the problem before then. Thanks again for the help!
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As I recall, a stock harness has one or two fusible links in the first 6" of wire starting at the battery cable on the starter solenoid. I would not swear to that or any other aspect of the factory harness, as I dont clearly remember the factory harness from my 83 c10, and it now has a painless harness, and my 76 k20 has a heavily modified 87 v20 harness. Replacement is commonly done by using a roughly 6-7" section of the appropriate size of fusible link wire (2 gauge size smaller than the wire its protecting), soldering a ring terminal (if applicable) to one end, and soldering the other end to the harness (*please* use heat shrink tubing with heat sensitive adhesive, or double seal your connection by using a liquid electrical tape/black rtv under standard heat shrink, or a high quality electrical tape such as 3m #88, or if not available, #33 under an extra long length of standard heat shrink)
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Had a pretty miserable weekend trying to fix this problem. The truck is being so weird and I have cut wires/spliced wires everywhere from the p/o. I might just start a new thread in a more appropriate location.
If i pull the headlight switch i lose all power to my ignition and dash. Blinkers, wipers, ac blower all still work. If i dont touch the headlight switch and try to start the truck it cranks longer than usual, fires up, and immediately dies. At one point this weekend it all of a sudden started up great and ran for 15 minutes. I started cleaning up tools since it was getting late when suddenly it died again and i was back at square one.
This weekend i replaced 1 fusible link that was cracked, replaced the headlight switch, swapped in a second steering column with no luck so i went back to the original, sanded every ground i could find so there was no rust, checked continuity across all the fusible links i could find, pulled out the junction box near the booster and reconnected it, and wiggled every wire i could find.
I know the truck will start when the engine light comes on with the key switched on. If i switch the key on and dont get the check engine light it will crank until the check engine light comes on and then start after. In all cases it immediately dies. Theres no rhyme or reason to when the engine light will be on. Sometimes if i turn the headlights on and off the light wont come on for an hour, sometimes it will come on no matter what i do. At this point i feel like im causing/ creating the potential for more problems than im fixing. For instance when i swapped the steerint column i found part of the firewall was rusted through and some chunks of rust broke free leaving some holes.
My thought right now is that the truck is being shorted out and wont give me the engine light until the motor starts cranking over increasing the current. Once it finally starts the current draw decreases and it dies out again due to the short. Is that a reasonable statement? I dont have any clue where to go with this next.
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http://forum.73-87chevytrucks.com/smforum/index.php?topic=33738.0
new thread in the electrical section now.