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I finally got blown
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MODS may want to make this a sticky

I stole this from another forum to help us out, i'm no tranny guy so i cant help anyone but this can.


Common failures on 4L60E, symptom -> cause -> any possible repair:

1. Slow, slipping or no reverse: “lo-reverse” clutches are worn out, fluid leak in the reverse apply circuit, or broken sunshell. It is possible to remedy a fluid problem by removing the checkball from its cage in the case in the rear of the trans may help (must remove valvebody), or adding a high-viscosity additive such as Lucas Transmission additive or other seal restorer product. May also have worn boost valve (can replace in the pan).

2. 1-2 shift does not happen at WOT until you let off the gas: Best case: try replacing the TPS. Middle case: leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator). Doublecheck by using the pressure gauge and watch for a big drop when the PCM commands 2nd gear. Worst case: poor line pressure rise (see below).

3. 1-2 Shift shudder at WOT; delayed or abnormal 1-2 shift; There's a problem ONLY on the 1-2 shift: 1-2 accumulator piston cracked or stuck cocked in the bore. Check the yellow spring inside the accum housing for breakage. Also, if the accumulator housing walls are scored, the housing must be replaced. Easy fix in the pan.

4. 1-2 shift is delayed and harsh, may not shift into OD: Check TPS for smooth and linear electrical response over the entire range of motion. If not, replace.

5. Trans does not upshift out of first, speedometer reads zero at all times: VSS failure. Easy fix on rear of transmission, but xmember must come out to access VSS.

6. No 3rd or 4th gear: “3-4” clutches are worn out. R&R. The car is safe to drive (in 2) until you can get it fixed.

7. Sudden grinding noise with no prior warning primarily in 2nd gear, behavior in reverse may be abnormal; sunshell is fractured. R&R. Try not to run or drive the car or further damage could result.

8. 1st and 3rd only, no 2,4 or R; sunshell is fractured or splines are sheared off. R&R. Try not to run or drive the car or further damage could result.

9. No 2nd or 4th gear. 2-4 band is slipping. Servo seals may be damaged (can be fixed without removing trans. Otherwise, 2-4 band is worn out. R&R.

10. Trans shifts into gear harshly, 3rd gear starts, manual 2nd available but no 1st, no 4th, and no TCC lockup: No power to transmission, or trans is in limp-home mode. Check trans fuse underhood, and make sure transmission electrical connector is plugged in. Easy fix.

11. No 1st or 4th available; trans shifts 2nd to 3rd by itself in D or OD : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

12. No 2nd or 3rd available: ShiftB solenoid failed: Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

13. No TCC lockup: Brake pedal switches improperly adjusted (always on), TCC solenoid failed (easy fix in the pan), TCC clutch worn out (must remove trans and replace TC).

14. TCC always locked: TCC apply solenoid circuit shorted to ground, TCC solenoid blockage (easy fix in pan), or TC broken (must remove trans and replace TC).

15. Horrible noise in 4th and feels like the brakes are on: overrun clutches are applying due to a cracked or leaking forward piston. Overrun clutches will be worn out after 30 seconds of this behavior. Car can be safely driven in D. R&R.

16. Soft shifting, gradual performance degradation: Poor line pressure rise due to leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or worst case: leaky seals throughout. Transgo HD2-C kit fixes first two without removing trans. Seal restorer may fix last problem, but probably R&R. Also try a transmission flush with BG brand products (Firestone stocks it).

17. No forward movement in OD or D, but L2, L1 and R work: Forward sprag is broken. R&R. Try not to run or drive the car or further damage could result.

18. Extremely harsh shifts from P or N, normal shifts at WOT: EPC (Electronic Pressure Control) solenoid failed. Easy fix in pan. Fix as soon as possible or hard parts will eventually break.

19. Loud bang, grinding sound, loss of all gears, and a binding driveshaft: snapped output shaft. Try to wiggle driveshaft - if more than 0.020" play, that's the sign. R&R.

20. Trans seems noisy when moving in 1st and Reverse, noise goes away instantly if you shift to N or the trans goes into 3rd gear: Reaction planetary is worn out due to high miles or insufficient lubrication. Not a critical failure, but not a good sign either. R&R sooner rather than later.

21. No movement in any gear: pump failure, or total loss of fluid. R&R, or refill pan and find the leak. If out of fluid, avoid running the engine until the trans is refilled to avoid pump damage. To check for pump failure, check fluid level with the engine off, then start the engine and recheck fluid level. If level does not go down when engine is running, the pump is broken.

22. Transmission does not shift automatically, only manually. Swap in a known-good PCM, check wiring, check other sensors such as VSS and TPS.

23. 3rd gear starts, can manually shift through all gears. When car has been turned off for a bit, then back on it will run normally.: VSS dropoff w/ Hi-stall converter. The rpms are too high, but VSS is showing no movement. Happens after a tire burning take-off. Doesn't store a code, will not throw a CEL (I've heard that it will store a code if it happens 3 or more times). Cure: Reprogram PCM for VSS dropoff -- PCMforLess knows about it.

24. Car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmision is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the underhood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.

25. Fluid leak out of the front of trans where the converter connects; partial or full loss of movement: Front pump bushing walked out. R&R. May have to replace converter also if hub is scored. Note that a leaking front seal usually means the bushing is walking out (i.e. call your local trans shop and schedule an appt.).

26. Torque converter shudder in 4th while lockup is engaged; problem goes away when the brake pedal is pressed slightly to unlock converter. Have a shop verify line pressure, and provided no valves in the TCC hydraulic circuit are worn, replace the torque converter. Also, Lubegard Shudder Fix will at least fix this for awhile. Or try a transmission flush by a shop that uses BG brand products.

27. Shift suddenly become very hard. When going from park to either reverse or drive it slams into gear. 1-2 and 2-3 shifts are also harsh. All gears seems to work. Problem may be intermittent: Check TPS for smooth electrical response. If the response is jumpy or erratic at all, replace TPS.

28. All fluid pumped out through the vent tube: Plugged cooler line. Flush the transmission cooler and cooler lines. Also could be overfiled transmission.

29. Car acts like it's in OD in neutral, car is locked stationary in R, engine feels loaded in P, all four forward positions work fine:Internal crossleak feeding the forward clutches all the time. Most likely a cracked input housing. R&R required. Car can safely be driven gently in forward gears until the repair.

30. Needle bearings in the pan, first gear and/or reverse may be noisy: Either a torrington bearing or a planetary bearing is on its way out. Trans will eventually die a loud, catastrophic death. Cheaper to rebuild now (saves further damage to hard parts), but requires R&R. It is drivable until it breaks.

31. 1-2 or 2-3 shift is slow/soft above part throttle: Trans is on its way out. R&R.
 

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what about a 2-3 clunk/ bang under light load, but other gears shift fine.
 

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what about a 2-3 clunk/ bang under light load, but other gears shift fine.
Some vehicles may exhibit a clunk noise that can be heard on a 2-3 upshift or a 3-2 downshift.
During a 2-3 upshift, the 2-4 band is released and the 3-4 clutch is applied. The timing of this shift can cause a momentary torque reversal of the output shaft that results in a clunk noise. This same torque reversal can also occur on a 3-2 downshift when the 3-4 clutch is released and the 2-4 band applied. This condition may be worse on a 4-wheel drive vehicle due to the additional tolerances in the transfer case.
This is a normal condition. No repairs should be attempted.




this is a bulletin from GM that i found. it is considered a normal condition. i'd still do the preliminary checks to make sure all driveline components are in good condition
 

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needs a bigger truck
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damn, i could have used this a few years ago... had my tranny serviced, then a week later it puked outta the vent tube. damn bastards must have overfilled it. ended up buying a new one.
 

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goin broke but n style
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My tranny has clunked since 13,000 miles. at over 130,000 it is still fine.

While under warranty I took it to 2 diff dealers adn they both said it was normal.

HIGH RPM'S IS WHAT KILLS THE 4L60E. IT WAS ONLY DESIGNED TO TAKE 6200 RPMS NOT 7,000. NOT TO MENTION HEAT.
 

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I have a ?. 2nd to 3rd in my turck, it seems to rev up a little then shift, no clunking or banging. just revs up a little bit. and its only 2nd to 3rd. I just had the fluid changed to see if that would help and still does it. And it only does it certain times like half throttle. Wot its shifts fine doesnt rev up. Any ideas?
 

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goin broke but n style
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how many miles and what year? Is it factory or has it been reprogrammed?
 

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1996 4.3, 92,XXX miles, don't think it was programmed, some old guy owned it before me and i didn't do it so. Only things i did were oil change intake and exhaust and tb mod, but i don't think they would have anything to do with it.
 

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24. Car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmision is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the underhood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.
I have this problem when I put in TCI race fluid. Only happens when tranny is cold. When I drive for about 10 min. or so (manualy shifting 2nd and 3rd gear of course) and then turn off the engine and wait about 10 sec. (almost like I am resting something?) it works fine like nothing happened. Works fine until I stop driving and the tranny cools back down to being cold. Any thoughts?
 

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Anyone know why my trans drives fine untill 3k RPM and then slips under any throttle position
 

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great info, found my problem on 1st and 4th!
 

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Just to add a little info. I have a 98 Blazer 2wd and the tranny would work fine for hours of driving and then all of a sudden shift hard through all gears and continue doing so until it sits overnight and then it might not do it again for a week. I took it to my tranny guy and he hooked it up on their scanner which can scan codes my OBDII reader can't. It threw out a code and he said that it's a common problem in these tranny's and a transgo shift kit would fix it. It's not one that jerks when it shifts or anything, but it will fix my problem he said. The kit ran me $30 shipped off of ebay.
 

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27. Shift suddenly become very hard. When going from park to either reverse or drive it slams into gear. 1-2 and 2-3 shifts are also harsh. All gears seems to work. Problem may be intermittent: Check TPS for smooth electrical response. If the response is jumpy or erratic at all, replace TPS.




what is tps? my truck does this exact thing and it was caused by large amounts ofwater getting in or around the tranny. wounld the only way to fix that to be replace the tps?

by the way i have a 99 sonoma with a 4.3 auto with about 86000 on it.
 

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I currently have this problem in my 1999 Bravada does anybody else have anything to add or suggestions?

also, does VSS mean Vehicle Speed Sensor and where is this located on the truck?

22. Transmission does not shift automatically, only manually. Swap in a known-good PCM, check wiring, check other sensors such as VSS and TPS.

another question I have, if this is my problem does that mean that physically the transmission is ok?
 

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Ok I didnt see one like mine wo any help.

1996 with 88k miles. under WOT it will sometimes shift 1-2 or 2-3 and I can tell it shifted and the engine revs up a lot but no power is going threw (kinda like its in neutral). As soon as I let off and ease back on it is fine. Also it has become very hard shifting from P or N into D but also just sometimes.

I just had it entirely rebuilt 15k miles ago so I'm really hoping its something small and stupid.

Any help please???:(
 

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What about no second or reverse? I changed my fluid a few weeks ago as well as this morning, double checking the filter engagement and still no second or reverse. Truck has 140,000mi and I need it to go more. Any ideas on what could cause this and any soulutions?
Please reply.
thanks,
Al
 

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I have symptoms of #17. It won't start out in D or OD unless it revs real high and kicks in. Almost 4K. I can shift it to first and second and it starts off fine then I shift into D and OD with no problems.
 

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How about truck runs fine in 1st and Reverse, when it shifts from 1st to 2nd it locks up the drive train like you just nailed the E brake. In 2nd feels like you driving with your foot on the brakes, and jerks like it's trying to lock up again.
 
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