Determining TH350 length
 

Without having to get underneath and measuring the transmission, since I am in different state right now than my truck, is there a way to determine if I have the short or long version of the TH350 transmission?

My guess is I have the short version, because I have a K20 and the transmission sits between the 350 motor and the transfer case.

Reason why I ask is I would like to put a transmission with an overdrive in, without having to invest in a new front or rear driveshafts due to having to move the transfer case location if the new transmission would be too short or long than the TH350 that I have in there now.

My understanding is if it is the short version of the TH350 the 200R4 would be the best replacement. While if i have the long version of the TH350 the 700R4 would be better transmission to go with.

What are your thoughts? I know I'm probably missing something.

Re: Determining TH350 length
 

Length difference is in the tail shaft.
However, The main cases are all different lengths.
Chart here gives you numbers.

https://ls1tech.com/forums/automatic...imensions.html

Re: Determining TH350 length
 

There is no difference in the transmission length in a 4wd. All the same from the bell to the adapter face. Keep the t-case in the same place and move the engine accordingly if you do not want to do drivelines

Re: Determining TH350 length
 

This. But there are (3) different output shafts. Short tail, long tail, and 4x4 as kwemch says, you have a 4x4 trans and any replacement would need be same. We just rebuilt the guts from one into another and the second looked like someone had physically cut down a 2x4 shaft to make a 4x4.

Re: Determining TH350 length
 

Ok

Re: Determining TH350 length
 

Yes in 2wd, you have the 6'' and the 9''. Only one in the 4wd for both the 203 and 205 t-case

Re: Determining TH350 length
 

6,9, or 12 inch tailshaft is the only difference. all 67-72,s had 6 inch tails

Re: Determining TH350 length
 

excellent diagram

Re: Determining TH350 length
 

Thanks for all the info!

Re: Determining TH350 length
 

I know this is an old thread but I found it by searching th350.
Thanks for mentioning they all had the 6 inch tails.

Re: Determining TH350 length
 

No, THM350's didn't all have 6" tail shafts.
There is a 6", 9" and 12" tail shafts for a THM350.
There are 4 different output shafts if you also include the 4 wheel drive.

In four wheel drive applications they didn't have any tail shaft attached. The transfer case is the tail shaft.

To add a overdrive you would most likely be installing a 700R4 also know as a 4L60. (Add an E after the number for the electronic version)
The transmission case is longer. So only options ares to change the driveline length(s) or move the motor.
Moving the motor leaves the 4X4 shifter in the stock location. The shorten the drive-lines option moves it back 2-3/8".
21-5/8 to 24" A 2-3/8" difference in case length.

Re: Determining TH350 length
 

All 67-72 two wheel drive with 350 Turbo's had a 6 inch tailshaft.

Re: Determining TH350 length
 

I didn't know that you could get a TH-350 in a 67.

Re: Determining TH350 length
 

Good point as the THM350 was first built in1969!

Re: Determining TH350 length
 

I think the consolidated point they were trying to make is the 67-72 that did come with a TH350 for a 2wd had the 6 inch tail?
So, to tag this down.. If it wasn't until 69-72 for the TH350 in a C10, was it only the 6 inch tail in a 69-72 2wd 1/2 ton Chevy truck?