I've been having a problem with my transmission for awhile now and I'm not sure what's causing the problem.

It's a good 'ole 700R4

The symptoms are: when I put the transmission into reverse it begins to knock ..... as I accelerate in reverse the knock gets louder and faster with the engine speed..... sounds alot like engine knock but I'm about 99.5% sure that it's the transmission.

This ONLY happens in reverse. I never have any noises or problems when in drive or park.

Here's the interesting part.... if I put the car on ramps, unbolt the flywheel from the torque coverter, push the converter back, rotate the torque converter a few times and then bolt it back to the flywheel it helps with the problem. For awhile, it will only knock in reverse occassionally and then gradually over time it gets worse again.

I've checked out the flywheel fairly thoroughly and am fairly certain that the flywheel is not cracked or broken.

Any ideas? I know it "could" be the torque converter or the front pump has gone bad or it "could" be any number of problems with the internals of the transmission.

Has anyone had a problem similar to this and found a solution?

 

i don't kow the answer but sometimes my tranny does the same crap!

 

I had a similar problem with my 66 mustang. Would knock and clang in reverse. Mine ended up being the torque converter.

Replaced it and the noise went away.

But Iam new to third Gens. SO it might not be the same thing.

Bruce

 

Well considering that it gets better when I mess with the torque converter, I've been thinking that it's got to be either the torque converter or the front pump... I just hate to spend the money on the torque converter and then find out that there's nothing wrong with mine....

 

Do you have a lock-up converter?

 

Yes I do but it never has locked up because from the day I put the transmission in the car, it hasn't had a vehicle speed sensor (the sensor is there but there's no gear behind it) so the speedo doesn't work, the speed limiter doesn't work, and the lockup doesn't work.

 

Just shooting in the dark here, but is there wiring to the tranny for the lockup? Don't know a whole lot about these newfangled gadgets... If there's wiring, is there a possibility it could be shorting out when you put it in reverse, trying to lock up the converter?

 

Actually I don't think that's possible either.... and here's why.

When I installed my new B&M mega shifter, I didn't actually hook up the fancy micro switches that came with it to let the computer know when the car is in park, neutral, etc ..... I just simply unbolted the factory selector and set it to the side under the console ..... still hooked up of course. The computer always thinks the car is in Park even when it's in drive. I tested this out one day by using my Auto XRay to get some data while driving down the road. I could be doing 50mph and the data would show that I was in park.

Therefore, the computer doesn't know I'm in reverse so it can't be sending any type of signal through the wiring to the lockup for it to short out.

However, just for the heck of it, next time I'm under the vehicle I will give your theory a test and I'll let you know what happens (or doesn't happen).

Thanks for the idea!

 

Any luck yet?

 

Have you checked yours transmission mount. 700's are notorious for that breaking.

 

when I put it in reverse it bangs.
Theres play in the differential yoke.
I removed the drive shaft and a cap broke loose on the
UV joint.
With the driveshaft removed I can turn the yoke 1/2 inch
before it turns the wheels.

 

I have had several of these cars and every time I take out the trans I put a washer and a Lock washer between the flywheel and the torque convertor. I have a friend that says "Dont you think that GM knew what they were doing when they designed it".

There is a truth to that statement but GM engineers had to build parts that were interchangeable to several different vehiles. Those of us who drive these cars know that most of the parts that GM put on these cars are not high performance.

The set up that is on your 3rd gen is on trucks, cadillacs, and are not intended to take the abuse. GM just needed it all to work as cheaply as possible.

If you use my idea make sure that you buy a slightly longer bolt that is hardened high grade steel