NTIMD8

iTrader: (17)

Engine (Heads and Cam LS1)
Tranny (4L60E with TCI 3200 Stall Converter)

Pinned it in second gear and it downshifted normally and pulled hard to redline. When it was time to shift there was a loud bang (maybe the sound of the rev limiter/fuel cut) and the car hesitated violently (did not shift into 3rd gear). I immediately let off the gas. Car drove fine after that for the next few minutes. Shifted fine under normal acceleration. Then it felt like the tranny started slipping. I eventually could not go over 30mph and then after another minute or so it got worse and worse and couldn’t get the car to go over 5mph. I was lucky enough to be pulling into my driveway at that point. I let the car cool down and tested the tranny. The car will hardly make it up my driveway. It feels the same way in reverse. Just revs with very very very weak acceleration. I tested the stall in drive with one foot on the brakes and the other on the gas pedal and it did not stall at 3200RPM. It just revved to redline.

I was thinking the TCI converter took a dump (broke stator??) Or maybe something like the filter is blocking flow of the tranny fluid so I am not getting line pressure?

I have access to a hoist at my buddies house but would like to get the parts needed to fix it before puting it up but I have no idea what broke or how to tell what broke. Any ideas from tranny experts would be very appreciated.

Thanks!!

mrvedit

I'm no trans expert, but the bang indicates something internal broke. It could be the oil pump which might give those symptoms. Really no way to tell until it is removed and taken apart. Putting a pressure gauge on the trans would give some clue, but I'm sure it needs to be removed and opened up anyway.

Are your going to rebuild it yourself or take to a trans shop?
Either way, I would recommend a rebuild with performance parts.
What year is the trans?

NTIMD8

iTrader: (17)

Thanks for the input. The tranny is a 1998 but it was rebuilt not long ago and has less than 5k miles since the rebuild. If the tranny needs a rebuild I would get it done at a shop (I do not have the time or know-how to do it myself).

PS, the loud bang could have been the violence of me hitting the rev limiter since it didnt shift into 3rd.

therabidweasel

iTrader: (5)

Sorry dude, the loud bang was most likely the tranny and not the rev limiter...rev limiter doesn't bang and doesn't cause you to stop moving in any gear...sorry, it sux.

NTIMD8

iTrader: (17)

Booooo. lol

I just cant remember if it was a mechanical bang or just like an instant loss of power bang (I.E. Max power to no power instantly) but ya I am thinking it was the tranny as well. I just have no idea how to diagnose it without having the car towed to a tranny shop. Would a tranny shop be able to diagnose if I took just the tranny to them? To have it slipping in every gear including reverse there has to be only a limited number of possibilities of what let go.

mrvedit

Since you had some movement in all gears, it not the input shaft/drum or output shaft or planets. I think it is the pump.
However, I know very little about torque converters and whether that could be your problem.

You could isolate the pump or converter issue by buying a transmission pressure gauge (about $45 on ebay) and connecting it to your trans. 75 lbs+ pressure (and 125+ in reverse) means your pump is OK. That test would save you the trouble of removing the trans if it is the converter.

However an expert on converters will have to chime in here.

NTIMD8

iTrader: (17)

Appreciate the info! Thanks!

z28camaro82z

as mrvedit specified, testing line pressure would be a good place to start. This could be attributed to line pressure due to pump failure, but generally pump failure gives you no motion in any range. It could be a large leak somewhere in the hydraulic circuit if you broke a forward piston or one of various other possibilities. The smartest idea would be to get a gauge on it even though I'd have to say you're probly gonna end up pulling that trans one way or another!

NTIMD8

iTrader: (17)

OK tested the line pressure and this is what I got...

Idle in Park (60psi)
Rev it up in park and it shoots to 210psi and then drops back down to 60psi when the revs come down
Drive (65psi)
Reverse (90psi)

Are these numbers normal for a 4L60E?

If those trans pressures are normal I am thinking I need to replace the converter. If they are not normal then built tranny time?

So not sure if this is the pump, valve body, stater in the converter or something else?????

mrvedit

Those numbers sound right and agree with the stock numbers listed in the ATSG manual.
Reverse is higher than drive because the boost valve is partially activated.
In detail, the 210psi sounds a bit high, but it indicates your pump is working fine. (See EDIT below)

I don't know if a converter could "break" with a bang and slip this badly.

I'm pretty sure you will have to pull the trans, but test these things:
1. Does it work OK in Reverse?
2. Put the trans into D1 or D2; does it drive OK then? (Don't go more than 1/4 throttle)

If it drives OK in Reverse, then it is not the torque converter. It is likely the forward sprag or the forward piston/clutch in the input drum.
If it drives OK in D1/D2, then it is likely the forward sprag broke; this may have dumped enough loose metal to warrant a complete rebuild with cleaning.

EDIT: I just hooked up a pressure gauge to my trans and blipping the throttle also jumps the pressure to 225psi, so that is normal.

NTIMD8

iTrader: (17)

Thanks for the input! It slips exactly the same in Drive, Reverse or D1, D2. No matter what I am in I can get the car to move very slowly (less than 2MPH) if I rev it up. At this point I am thinking converter. Its a TCI and I have heard stories of them not lasting very long.

mrvedit

I don't know enough about converters to give any advice.

Hopefully a trans AND converter expert can look at all these facts and make a diagnosis.

NTIMD8

iTrader: (17)

Thank you very much for your help!!

A friend who is a tech asked the tranny expert and basically he said since the pump is working, there is no obvious hard part failure, there is no way all the clutches failed at once, there are no codes so the solenoids are ok and there is a little movement it all points to a broken stater in the converter.

malibutwins

iTrader: (1)

I think converter. Pull pan check for debris

NTIMD8

iTrader: (17)

Just thought I would update the post. It turned out to be the converter. Put a new one in and everything works great now.

mrvedit

Thank you for the update; that is always very much appreciated by everyone that posted. And now I know a bit more about converters! Glad you didn't have to rebuild the trans.

NTIMD8

iTrader: (17)

No problem. I know I hate it when I read a thread and there is no update and resolution.