Bought the car with a bad rearend and tranny a year ago. Replaced the rearend without any prob. Tranny has been something else. First 700R4: Rebuilt ourselves worked fine for about 2 weeks. Then I lost 3rd and 4th. So we figured we messed up on the rebuild somewhere. Swallowed our pride and bought a used 700R4 in "good" condition. Installed and took off. Found out about TV cable being able to cause prob's with ease. Replaced TV cable and adjusted according to the book.(Have since read some of your posts and have printed some of your recommendations on TV cable installation.) However, within a week and a half I have lost 3rd and 4th again. Fluid is dark so I figure clutches for 3rd and 4th are burnt. Question: What would cause two different 700R4 to end up with the same malfunction within the same amount of operation time in the same car? Any help will be appreciated. I am willing to give more details if needed. Thanks

 

tv cable misadjusted, or being adjusted right but something allows it to shift positions. say broken motor mount or transmission mount that allows it too shift the tv cable out of alignment.

could just be you have bad luck. probaly not.

was it slipping going into 3rd or acting up at all? or did it just all of a sudden not have 3rd and 4th.

 

On the second Transmission it started slipping going into 3rd and 4th and then by the time i got home 3rd and 4th were gone.
So it is possible for a misadjusted TV Cable to cause the loss of 3rd and 4th?

 

I dont know that much about them, but do you know if your lockup was working? I have been told by a couple of mechanic friends that without the lockup that you can burn up a 700r4 driving across town. Just an idea.

Ben

 

Any other ideas or is it a good chance the TV cable caused the loss of 3rd and 4th? Thanks

 

TV setting is critical on these, along with TV geometry. Besides that, 3-4 failure is extremely common and is probably the first thing to go with a HP use type vehicle. Along with this is any contamination that was left in the cooler can and will stick the throttle valve in the VB and then you get no line rise or occasional no rise which will kill a tranny in short order.

 

I just bought a 1990 IROC a couple weeks ago. After picking it up in Bakersfield, Ca... I lost 3rd and 4th going up through the Grapevine. So I took it back to the guy and he said he'd have the transmission changed.

A week later he delivered the car and it didn't kickdown from 4th to 2nd when getting on the highway. I tightened the TV cable to get the kickdown, and it shifts at 5000 RPM at WOT.

Now I'm starting to have the same problem again, 3rd gear is going away and the car's currently at the shop getting looked at.

The relevance to this thread is: I printed the article on how to set the cable, but how do you know it's in the right place? I thought I had it in the right place but the problems are back. Maybe the answer to this question will help LTaylor6996 as well.

Thanks.

1990 Iroc-Z 5.7L / 700R4

 

If you have followed the TV setting procedure then try this: At minimum throttle, accelerate very slowly till you JUST get a 1-2 shift, then immediately floor the peddle, if it is working properly it will kickdown to 1st gear. That all being said, TV adjustment is only part of the picture. While it MUST be set and working properly, the internal components that IT operates also have to do their job and stock or homemade mods just don't fix this tranny, yes including giant Servo's and Boost valves. If the TV pressure that gets the ball rolling doesn't work right neither do they!