1967 TH 400 Auto transmission rebuild
 

A few months ago I took a slow drive around the block in the 67 GTO I am restoring. After I backed the car into the garage, i heard a slight groan / grinding sound then transmission fluid started puking out from the transmission cover between the engine and transmission. The car has been sitting since.

Yesterday I pulled the transmission ( 1967 code PS turbo 400). I am going to have it checked out, but was wondering if I should consider any performance upgrades during the rebuild? Also , what would be a good torque converter stall speed to use?.

The engine is basically a stock 67 400 and the car is restored like stock.

for a stock car a stock build will more than suffice... adding a shift kit won’t hurt so you can impress your friends with a 1-2 chirp

Assuming you’re also running a stock converter, a little extra stall might put a little spunk into your driving enjoyment as well. Stall speed will require a bunch of info including your driving style and typical use.

if the fluid is red, then you may want to reuse the converter.

Also, you may want to warm the engine up on level ground, run the TH400 throught the ranges R N D 2 1 back and forth 10. times. Then check fluid level.

Then drive ot hard, really hard, and decide if it really needs a rebuild. Might just need a new filter.

Early 67s still used the canister style filter. Shops prefer using the later valvebody, so they
can use the more common filter. 3 dimples and a heelprint on the pan help identify the
early stuff. Not exactly a big deal, but they might want some coin for another valvebody
so this is more of a heads up?? HTH.

The TH400 is probably "THE" easiest transmission there is to rebuild. All the clutches in front, all the gears in back, and no pistons pressed into the case.

I would use a Transgo shift kit in preference to B&M, TCI, etc.

A relatively stock engine might benefit from a switch-pitch torque converter. They were still making them in '67, although it was the last year. If you don't already have a switch-pitch converter, you'd need some internal parts to make it work, and an external controller. Most guys just use a slightly-higher stall speed "ordinary" converter.

The transmission is an early 67 with three dimples, heel stamp, and canister filter. the fluid was red and the inside of the transmission looked clean. There was a coating of black on inside bottom of the pan though.

I had not heard of "switch pitch" converters before so i did a little reading on them. Decided not o pursue that route and stick with an original style converter. I could not find any information on what is a factory stock torque converter stall speed for this car. any ideas and recommendations on what stall speed would be good?

Do a stock rebuild you will get real sick and tired of the bang shifting caused by those transmission kits..

Thus my recommendation to avoid the B&M kit in favor of the Transgo. Of course, retain the vacuum modulator.

A higher-stall torque converter also tends to soften the harsh shifts.

Totally normal.
Consider merely replacing the filter. See what happens. It'd cost you a filter and gasket kit, some fluid...and maybe save you a rebuild.