Transmission Problem

Joined
Feb 5, 2008
Messages
688
Location
Atlanta, GA
I just purchased a 2001 Corvette on Monday. It has 144k miles, 5.7L, and an automatic. I test drove it twice, and drove it home nearly 70 miles. I parked it in my garage for a day and came then drove it on Wednesday morning. As soon as I get to a highway about a mile from my home, the transmission will not shift past second gear. When it is supposed to go in to third gear, it feel like the engine and trans disconnect like I shifted in to neutral. The engine will just rev high and then it will catch back on to second gear rather violently.

I assume the transmission is done and will need a rebuild which saddens me as I wasn't really planning for it and did not detect any transmission issue before purchase. From my understanding this is not an uncommon issue with stock 4L60E transmissions burning up a clutch pack prevent 3rd gear and up. There are no transmission related codes (used OBD2 scanner with Torque app and the built in instrument panel DIC code reader). The only thing I can see visible is a cracked neutral safety switch/range selector. From what I've read, that wouldn't cause the issues I have.

https://www.youtube.com/watch?v=ItwCvpVyOjw

Anything in particular I can check to verify if this needs to be replaced?
 
Can you check the fluid level? Also it may be a computer issue, try disconnecting the battery for a bit. If no change scan to see what it says.
 
I'd add remove some fluid and put a bottle of Lubeguard red in there. What's to lose? If the fluid looks dark and dirty, change as much as you can as the viscosity will be quite low. Is the right fluid in there to begin with?
 
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Seems a little weird that it would go from shifting fine to no gears at all. A friend of mine with a higher mileage Sierra with the 4L60E just put a rebuilt in after putting up with it slipping into 3rd when he towed his trailer for a few months. It never actually failed. There is still a possibility something let go though. Just be sure before a full rebuild.
 
Originally Posted by tcp71
Check the fluid level before deciding it's done.


I put the car up on jackstands keeping it level. Let the transmission warm up to 100-120 degrees. Pulled the plug and nothing dribbled out. Added about 1.5 qts while running until it started to come out and test drove. It made no difference. Any other ideas?

Originally Posted by caprice_2nv
Seems a little weird that it would go from shifting fine to no gears at all. A friend of mine with a higher mileage Sierra with the 4L60E just put a rebuilt in after putting up with it slipping into 3rd when he towed his trailer for a few months. It never actually failed. There is still a possibility something let go though. Just be sure before a full rebuild.



It has gears...just the first 2.
 
The 3-4 Clutches are burnt down, Nothing short of a rebuild will fix it!

It doesn't technically neutralize, Once the 2-4 Band gets push off....The 3-4 Clutch is suppose to come on for a 2-3 shift. If the 3-4's are smoked, Your now back in 1st gear, But the road speed is too high & the Forward Sprag is overunning.
STOP banging against the Forward Sprag as it can break & take out the sprag race & input drum.
 
I never am surprised how people will buy things like this junk and they get hosed.
smirk2.gif
 
Originally Posted by AC1DD
I never am surprised how people will buy things like this junk and they get hosed.
smirk2.gif



How was he supposed to foresee this happening if it was fine on 2 test drives? Lots of 4L60E transmissions last over 300k miles. Unfortunately, not all of them do. Sounds like bad luck to me, unless the seller knew it had a problem and dumped a bunch of Lucas in it to get it down the road.
 
Originally Posted by john_pifer
Originally Posted by Olas
just fit a manual.


Yep. This is your chance.

Swap in a manual, like the car was intended for.


Not an option for me. I prefer the automatic.

Originally Posted by AC1DD
I never am surprised how people will buy things like this junk and they get hosed.
smirk2.gif



Right, because it wasn't shifting great for 20 miles of test driving and then perfect at 75 mph on the 70 mile drive home. There was no transmission leak under the car, and the temps were great. Thanks for the helpful response.

Originally Posted by caprice_2nv
Originally Posted by AC1DD
I never am surprised how people will buy things like this junk and they get hosed.
smirk2.gif



How was he supposed to foresee this happening if it was fine on 2 test drives? Lots of 4L60E transmissions last over 300k miles. Unfortunately, not all of them do. Sounds like bad luck to me, unless the seller knew it had a problem and dumped a bunch of Lucas in it to get it down the road.


Bad luck it is...

I will make some calls to transmission shops near me. How much should I be expecting to pay for a job like this?
 
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Any value in a different gearset for this transmission? I'm guessing it's not cheap but I think Sonnax has a 2.8 first gear option. It's a Vette and doesn't need a wide set of gears.
 
Originally Posted by RoGuE
I just purchased a 2001 Corvette on Monday. It has 144k miles, 5.7L, and an automatic. I test drove it twice, and drove it home nearly 70 miles. I parked it in my garage for a day and came then drove it on Wednesday morning. As soon as I get to a highway about a mile from my home, the transmission will not shift past second gear. When it is supposed to go in to third gear, it feel like the engine and trans disconnect like I shifted in to neutral. The engine will just rev high and then it will catch back on to second gear rather violently.

I assume the transmission is done and will need a rebuild which saddens me as I wasn't really planning for it and did not detect any transmission issue before purchase. From my understanding this is not an uncommon issue with stock 4L60E transmissions burning up a clutch pack prevent 3rd gear and up. There are no transmission related codes (used OBD2 scanner with Torque app and the built in instrument panel DIC code reader). The only thing I can see visible is a cracked neutral safety switch/range selector. From what I've read, that wouldn't cause the issues I have.

https://www.youtube.com/watch?v=ItwCvpVyOjw

Anything in particular I can check to verify if this needs to be replaced?



What does the fluid look like ? Low ? Dirty ?
 
Originally Posted by WyrTwister

What does the fluid look like ? Low ? Dirty ?


Pink-ish and gritty. It was low. It took 1.5 qts. It didn't make a difference.

I made some calls to transmission shops around me. Prices ranged from $1600-$2600 for a rebuild depending on what is damaged and what parts I want in it. One shop I called (Aamco of all places) seemed knowledgeable with the 4L60 specifically in the Corvette. They said they rebuild with a High Energy 2-4 Band and use Z Pak (Raybestos) 3-4 Clutches. Their price seemed in line with the others and they have an 18 month warranty. Being 3 miles away helps so I don't have to drive far enough to need it towed.
 
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Don't use Z-pak.....That crap is JUNK! Industry standard is 24 months for stock vehicles (Non-Commercial) If they are so confident in the Z-pak, Why not offer a longer warranty?

High Energy 2-4 band is factory equipment.

I like 7 .080" Borg Warner High Energy frictions & 6 .077" Alto Kolene steels in the 3-4 clutch along with......
*Apply Plate GM# 8685044
*Backing Plate GM# 24212460
Leveling the 3-4 Apply plate to +/- .002" is a very important albeit time consuming step that most don't bother with.

Stock, Your trans has 6 .080" BW frictions & 5 .106" steels.

*The Input Drum & 3-4 bleed capsule has to be carefully leak checked.
*Block the 3-2 downshift valve Inboard to prevent 3-4 circuit leaks, The Trans Go HD-2 shift kit does this with a tightly wound spring, I do it by machining an aluminum spacer.
*The 3rd Clutch exhaust check ball behind the 2-4 Servo needs to be checked for leakage, Small leakage can usually be fixed by reforming the ball seat with a few taps on the check ball with a brass drift & hammer.
*Sonnax .490" Boost Valve & Sleeve....HERE
*Sonnax Smart Shell.....HERE
*Sonnax wide PTFE rear Stator Bushing.....HERE
*Sonnax wide rear Sun Gear Bushing......HERE

All the Accumulator pistons & springs will need to be checked & replaced as needed, The 2nd Accumulator piston, Pin, & Spring will surely need replaced.

I like to block the PWM function on the TCC Apply, Trans Go has a fantastic drop-in replacement valve in their SK & HD shift kits, Unfortunately it's not sold separately. But the price of a SK kit is worth it just for this valve!! And they include a Pin so you can change Accumulator Pressure Control Springs without dropping the Valve Body.

The Separator Plate probably has some wear, Especially where the 2nd Clutch Checkball seats, Trans-Go plates are cheap enough.
 
Originally Posted by caprice_2nv
Originally Posted by AC1DD
I never am surprised how people will buy things like this junk and they get hosed.
smirk2.gif



How was he supposed to foresee this happening if it was fine on 2 test drives? Lots of 4L60E transmissions last over 300k miles. Unfortunately, not all of them do. Sounds like bad luck to me, unless the seller knew it had a problem and dumped a bunch of Lucas in it to get it down the road.



Thing is it IS a Vette, and you just know the likelihood of the PO abusing it is pretty good.
 
Originally Posted by AC1DD
Originally Posted by caprice_2nv
Originally Posted by AC1DD
I never am surprised how people will buy things like this junk and they get hosed.
smirk2.gif



How was he supposed to foresee this happening if it was fine on 2 test drives? Lots of 4L60E transmissions last over 300k miles. Unfortunately, not all of them do. Sounds like bad luck to me, unless the seller knew it had a problem and dumped a bunch of Lucas in it to get it down the road.



Thing is it IS a Vette, and you just know the likelihood of the PO abusing it is pretty good.


I don't know. I never really see Vettes getting abused around here. Maybe occasionally, but often it's just a retired guy who could finally afford to buy the car he wanted a long time ago, driving around getting some wind with the top down. I see trucks like mine, loaded with weight, lifted with 35" tires getting flogged up the road all the time.

I know I don't see many Vettes in comparison to a truck but every time I do, the owner seems to be pampering it.
 
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