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Old 03-28-2020, 04:46 PM
jhnichols2 jhnichols2 is offline
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Default 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.

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Old 03-28-2020, 07:28 PM
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mchell mchell is offline
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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.

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Old 03-28-2020, 07:37 PM
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Half-Inch Stud Half-Inch Stud is offline
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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.

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Old 03-28-2020, 07:44 PM
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242177P 242177P is offline
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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.

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Old 03-29-2020, 01:46 AM
Schurkey Schurkey is offline
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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.

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Old 03-29-2020, 05:46 PM
jhnichols2 jhnichols2 is offline
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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?

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Old 03-29-2020, 06:04 PM
389 389 is offline
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Do a stock rebuild you will get real sick and tired of the bang shifting caused by those transmission kits..

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Old 03-29-2020, 07:52 PM
Schurkey Schurkey is offline
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Quote:
Originally Posted by 389 View Post
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.

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Old 03-29-2020, 07:55 PM
Schurkey Schurkey is offline
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Quote:
Originally Posted by jhnichols2 View Post
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.
Totally normal.
Quote:
Originally Posted by Half-Inch Stud View Post
Might just need a new filter.
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.

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