Torque converter problem???

1980 Bu Baby

Member
Apr 4, 2014
6
0
0
Brief description: 1980 malibu, 7004r trans, 355 CID, 4.10 rear, 3 speed b&m shifter<<I know I didn't do it, "supposed" 3800 stall.
I purchased the car like it is for 1800.00. The guy told me that the trans was slipping. That's why the price was so cheap. Ok whatever. There are no malibus around here running in decent shape for that price. I will take it. I get there and the car has been neglected. But it's decent. I test drive it and the trans shifts super firm like it's been built.... NO SLIPPAGE!!! But also no 4th gear. I get the car home check the fluids and the trans is about a quart low. I add a quart and go through the gears manually and it limps into fourth but it's there. Every time I drove it from then one fourth was intermittent. But it came on. I drove the car today. It went into fourth and I was cruising at about 50 mph and roughly 3800 rpm and the fourth gear disappeared. I pulled over and checked the fluid it was a half quart low. Topped it off and tried again. No dice. THEN it felt like it was slipping in third no power what so ever but firm through the first two shifts. Then nothing. No manual up or downshifts period. Cut the car off wait like ten min start it up and there it goes. Shifts into second and into third then completely slips. No movement. Seems to me like the converter is done or the trans is jacked because he mis adjusted the cable considering he put a three speed shifter on a 4 speed trans and it's causing the trans to do funny things. Based on my knowledge I believe the converter is flawed and wasn't locking up causing an intermittent fourth gear engage then it just quit. Over heating is causing the slipping which explains why it shifts fine after it sits a few. But only after I cut the car off and back on again??? No reverse no nothing though??? What do you think. I know it's lengthy......
 
The torque converter doesn't know what gear the transmission is in. The problem you have is not related to the converter. All the converter is doing is spinning the pump rotor and the input shaft. Everything else is up to the transmission itself. Chances are good that the T.V. cable was never adjusted correctly and your 700R-4 is now burned up. Unfortunately your only option is to remove the transmission to have it inspected and repaired. The 3-4 clutch pack is going away, and I'm willing to bet that the 2-4 band is not far behind it.

You're going to need to get the torque converter cut apart as well. There will be debris from the transmission failure trapped inside the torque converter, so the converter is going to need to be thoroughly inspected and rebuilt.

The torque converter lock-up function will not have an effect on what gear the transmission does or does not go into. Fourth gear is fourth gear. The lock-up function in the converter is an independent feature from the actual forward transmission ranges.

A 3-speed shifter can be used on a 700R-4 without an issue as long as the shift linkage/cable is adjusted correctly. The 3-speed shifter will not allow you to manually access low gear, but apart from that it won't cause any problems.
 

1980 Bu Baby

Member
Thread starter
Apr 4, 2014
6
0
0
Understood. But... Every time I cut the car off and back on it shifts perfectly I'm talking firm up to third gear then about a mile down the road it stops everything. Until the car is cut off and back on. I mean immediate key cycle. Then it runs fine for a few. I know it sounds crazy but these are actual symptoms. If the torque converter has malfunctioned would it not transfer power to the input shaft of the trans? I know that the converter is essentially a fluid coupler. But if that action has "wiped" would it act like a manual car with a bad clutch. Basically is what it is doing. But I understand what you are saying just doesn't answer my symptom completely. Also I know the 3 speed shifter can be used but why??? I drag race and need full control of my shifting. The guy I got it from told me he did too and it's impossible like its set up. Everything is getting pulled out so no worries but if this trans is usable I will use it until it goes unless it has already gone. I have two more trans' laying around for a rainy day though.
 
There's not a whole lot that can malfunction inside a torque converter, and even if the converter did have problems such as a broken sprag, bearing failure, or damaged fins it would still not operate intermittently as you've described. The turbine spline could strip in which case the converter would no longer be capable of turning the input shaft, but when that happens you have no ranges at all.

The lock-up clutch doesn't affect transmission ranges. You could have a lock-up clutch that was completely burned up and it wouldn't affect how the transmission shifts. On the other hand you could have a lock-up clutch that is friction welding itself to the front cover of the converter, but in that scenario the engine will die as soon as you put it in gear because there would be no converter slippage present to allow the engine to idle in gear.

I'm not implying that a 3-speed shifter SHOULD be used on a 700R-4. I simply brought that up for the sake of the process of elimination regarding the transmission functionality issue.
 

MalibuRacing.com Gear

Stickers & Shirts!!

Quick Navigation

User Menu

Credits

© 2001-2022, All Rights Reserved.
Ripp Technical Services
A ForumGeeks Production.

MalibuRacing.com is a place to provide and exchange performance tech, tips, information and general discussion about the 1978-1983 Malibu and Malibu Classic. All A/G body fans and discussions are welcome here. Much of the information on this site applies to other years and models of the A/G body lineup.

Malibu Racing is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.