Gheld

I recently rebuilt the 4l60e in my Chevy 1500 due to a broken sunshell. The rebuild kit came with an additional spring with instructions to place it in between the two components of the TCC lockup valve. This caused the transmission and engine to lockup immediately upon releasing the brake in any gear. I removed it and this was resolved. Now, it will not go any where. If you get the RPMs high enough, she will just creep along. After running for an hour and a half and monitoring the fluid level, she drove fine with no problems. I parked her and the next morning I got in her to go to work and nothing. I have been asking everyone I know and they have no clue. Transmission shops just tell me to bring it in and they will rebuild it for $1000. I want to fix the problem not another rebuild. I decided to reach out to other sources. Does anyone have a clue what this is about?

johnp94

iTrader: (12)

I put a used tranny in my Camaro 4l60e, it would not shift out of first.It was the speed sensor on the tranny.

Gheld

This will not go anywhere. There was a problem with the PRNDL switch. The sealer in the switch would melt cause the plug to be stuck and when disconnected it could damage the plug or switch. The reverse lights on my truck will not work. I checked the fuse and replaced the bulb. Could this all be a result of a bad PRNDL switch?

Gheld

Alright, I replaced the PRNDL, or neutral safety switch, and my reverse lights work but no drive in any gear. The rebuild kit came with a spring that directed me to insert the spring between the valves of the TC Lockup valve. When the truck was started and brake was pressed you could put the truck into gear. As soon as you released the brake the engine and transmission would immediately and I mean immediately stop. Like something grabbed it and stopped it in an instant. I removed the spring and this no longer happens. Is it the most likely conclusion that the torque converter sprag busted and is now free spinning? I believe this would cause no power from the torque converter to be transferred through the transmission. With high rpms it will try to move but at about 1 mph. If you let it run for about 1.5 hours it will drive until it is parked and cools down. Then you have to start all over. The only answer I can get is from a tranny shop that wants to rebuild it for $1500.

mrvedit

The extra spring obviously messed up your TCC valve; GM had variations of that valve and that spring might have been intended for another year. Therefore the lockup clutch engaged the instant you released the brake pedal, stalling the engine.

Are you saying you have neither forward nor reverse?
Do you have a way to test line pressure, e.g. with a trans pressure gauge?
Try this:
1. Check your fluid level with the engine off.
2. Check it again with the engine running.
3. Tell us how much it went down; about 1" is normal.

Gheld

That is correct. I have no drive in any gear. The fluid level drops and I disconnected the return line from the cooler and fluid shot out under a lot of pressure putting me to believe the pump is working. I do not have a way to test the line pressure. I also do not know how much the tool would cost or where to buy a decent one. The sprag was the only thing I could think of, but I am unaware of its strength and durability.

mrvedit

For a trans pressure gauge, look up "ATD 5550" on ebay. Generally $50 with free shipping; looking up "transmission test pressure gauge" I saw similar ones.

Nice that you already tested for pump pressure. The sprag is often called the Forward Sprag because it is only needed in forward. About the only thing the forward gears and reverse have in common is the input shaft, the output shaft, fluid pressure and of course the converter. I am not familiar if a miss-assembled low-reverse clutch could give you your symptoms.
Have you tried putting the shifter in [D1] which then applies the low reverse clutch?

So far, I think you have extremely low line pressure for some strange reason.

Perhaps one of the pro builders here has more ideas.

Gheld

yes, I shifted through all selections. I am referring to the clutch sprag inside the torque converter. I read that if it is locked up that poor performance will result at highway speeds and if it spins freely that it will result in low speed performance.

Gheld

I didn't want to leave one of those common post that have no updates or display the results. The tranny was finally removed and torn back down. I did this so that I could go back through the whole thing, valves and all. I discovered that I had installed the tcc valve in the pump incorrectly. It is suppose o be springs first then the valve. I had installed the valve first and then the springs. This caused oil feed to the torque converter to bleed off into another circuit. That why it wasn't going any where, there was no fluid in the torque converter. I hope this helps somebody else and I wanted to thank all those that tried to help me resolve my issue.

mrvedit

Thank you or the update! I never would have deduced that an incorrectly installed TCC valve would result in no car motion at all.

For completeness, here is a picture of the order of parts for the Boost valve (top) and TCC valve (bottom) as they are installed into the pump. The snap ring pliers is the only tool needed to remove/install them.