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Username Post: TB400 Automatic Transmission repair        (Topic#339399)
Forum Newbie
Posts: 3

Reg: 12-19-11
09-25-16 10:42 PM - Post#2653305    

I have a 1960 Chevy C10 Apache with a 350 stock V8 and a TB400 3-speed automatic transmission.

The transmission used to shift very quickly from 1st to 2nd to 3rd, before 2500 RPM. Now, it makes a grinding noise when I take off from a full stop. It also will not shift to 2nd or 3rd. I think, though, that the transmission is stuck in 3rd. The rpm is high at about 3000 and higher, feels like the transmission is slipping.

I dropped the trans pan and found a paste like gray/black substance on the bottom of the pan. I also saw some of the bearing from the torrington bearing. Anyone have a fix? Transmission shops want to charge as much as buying another transmision. Thanks for your support.


Frequent Contributor
Posts: 2008

Loc: Lake George, NY
Reg: 11-11-15
09-26-16 04:20 AM - Post#2653314    
    In response to altownsend

Welcome to CT, the fix is an overhaul, no other way.

Forum Newbie
Posts: 3

Reg: 12-19-11
09-26-16 01:14 PM - Post#2653397    
    In response to Shepherd

you have, or do you know a member who has one for sale for cheap - one that works?

Posts: 27999
Loc: San Francisco, CA
Reg: 11-26-02
09-26-16 05:50 PM - Post#2653437    
    In response to altownsend

You could try salvage yards and Craigslist. Salvage yards will often give you a guarantee (replacement, not refund). Also, you can put a WTB ad in the CT free classifieds.


Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.

Forum Newbie
Posts: 3

Reg: 12-19-11
10-31-16 01:46 AM - Post#2659229    
    In response to raycow

I ended up buying a used transmission and installed it. The following is what happened.

A. I installed the replacement transmission and a new torque converter from Auto Zone, (did it by myself).

B. The new set-up worked fine (with one exception), drove the truck down my driveway and back. Next day, the vehicle would not move.
---The exception: There was about 1/2 (slightly more) space between the torque converter and the flywheel when I installed the new set-up.
---Talked to three transmission shops and all suggested that the pump was bad, or that I needed to shim the torque converter, moving it closer to the transmission.

C. Shimmed the torque converter, vehicle still would not move. Pulled the return cooling line (upper line), started the engine to see if the pump was moving fluid. No fluid came out of the return line. Presumed that something was up with the pump.

D. Removed the transmission again, pulled pump, and found the following.

D1. Both pump gear tabs were worn down about half way the gear.
D2. The base of the shaft where the pump gear rests on was worn at least 1/8 inch. Maybe this is why there was so much space between the converter and flywheel.

E. I pulled the pump out of the other transmission and installed it into the 'New" transmission and reinstalled the 'New' transmission.

F. No change, still will not move truck. I noticed that the torque converter was so tight that I had to loosen the transmission to rotate the converter, and re-tighten the transmission to the engine. Buttoned it all up and filled the transmission with fluid.

G. Started the engine and let it warm up. Put the transmission in reverse - nothing, in Drive, nothing.

Question: Could it be that I destroyed the pump gear again?
Question: Could it be that the other pump won't work in the 'New" transmission?

Both Transmissions are a TB400. The number cast inside of one pump was 44, and the other one had 38 cast inside of it. Does this mean something?

My first thought was that I ruined the pump gear again. Fluid was good, no noises, clinks, clanks, nothing when the engine is running.

Comments please.


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