Transmission identification - The 1947 - Present Chevrolet & GMC Truck Message Board Network

boondocksdrew · 06-20-2021, 09:09 PM

I'm trying to identify which automatic transmission is in this 1972 C20. The detents or something in the column shifter are worn out and it's gotten kind of sloppy. I'm considering trying to put a floor shifter and valve body kit in it.

It sounds like this truck would either have had a TH350 or a TH400 and the one in the pic pretty much has to be a TH350, right?

**LockDoc** · 06-20-2021, 09:47 PM

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Use this chart.

LockDoc

**Accelo** · 06-21-2021, 02:23 AM

Early thm350
The thm350 only had a drain plug for a few years. You will likely have fewer issues if you repair the column. The cab will stay quieter from fewer holes in it.
May even be less money than the replacement floor shift.

MARKDTN · 06-21-2021, 09:19 AM

Quote:

Originally Posted by Accelo

Early thm350
The thm350 only had a drain plug for a few years. You will likely have fewer issues if you repair the column. The cab will stay quieter from fewer holes in it.
May even be less money than the replacement floor shift.

This-agree!

**LockDoc** · 06-21-2021, 10:42 AM

Quote:

Originally Posted by Accelo

Early thm350
The thm350 only had a drain plug for a few years. You will likely have fewer issues if you repair the column. The cab will stay quieter from fewer holes in it.
May even be less money than the replacement floor shift.

Quote:

Originally Posted by MARKDTN

This-agree!

I almost posted this too. A little more detailed information on the trouble you are having would help to diagnose the problems. Is it hard to get in and out of park/reverse?

LockDoc

06-20-2021, 09:09 PM	#1
boondocksdrew Registered User Join Date: Jan 2019 Location: Charlotte, NC Posts: 1	Transmission identification I'm trying to identify which automatic transmission is in this 1972 C20. The detents or something in the column shifter are worn out and it's gotten kind of sloppy. I'm considering trying to put a floor shifter and valve body kit in it. It sounds like this truck would either have had a TH350 or a TH400 and the one in the pic pretty much has to be a TH350, right?

06-20-2021, 09:47 PM	#2
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,849	Re: Transmission identification - Use this chart. LockDoc Attached Images __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

06-21-2021, 02:23 AM	#3
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,308	Re: Transmission identification Early thm350 The thm350 only had a drain plug for a few years. You will likely have fewer issues if you repair the column. The cab will stay quieter from fewer holes in it. May even be less money than the replacement floor shift.



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