How to identify auto tranny type?
 

I'm trying to make sure what type of automatic transmission that's on my grandsons 1972
C/20 Delux. It has a 350 engine but not sure if it's a t350 or t400. It needs to be replaced and I want to make sure we get it right when looking for another. Can any one out there give me some sure indicators on what to look for to tell if it's a t350 or t400 on the truck now. It is the original tranny.
Thanks

Re: How to identify auto tranny type?
 

Here you go.

700r-4 also applies to the 4L60 and 4L60-E

Re: How to identify auto tranny type?
 

Those are transmission oil pan shapes. Compare them to yours to decide which one you have.

Re: How to identify auto tranny type?
 

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Here is another one.

LockDoc

Re: How to identify auto tranny type?
 

http://67-72chevytrucks.com/vboard/a...1&d=1520447840

Hope this helps ...:chevy:

Re: How to identify auto tranny type?
 

When you look for a replacement, make sure you get one with the correct tail shaft housing length.

Re: How to identify auto tranny type?
 

Yup. It'd be a bummer to get one with the wrong length tail shaft.

OP- see if you can post a picture. It can save a lot of pain. What are the symptoms that you deem make replacement necessary?

Re: How to identify auto tranny type?
 

It slips bad in first gear when starting out, unless you baby it when you take off.

Re: How to identify auto tranny type?
 

I would have yours built instead of getting another. You know it fits, you know a little about it. It has to come out anyway, just build it. But you might service it and it may go a bit longer. Could be the filter is clogged. I would at least pull the pan and take a look.

Another tell-apart is a TH350 has the vacuum modulator at the rear of the trans while a TH400 has the modulator on the right side towards the front.

Re: How to identify auto tranny type?
 

Check the SPID.

Re: How to identify auto tranny type?
 

Another...late transmissions do not have vacuum modulators, oldies do...

Powerglide, modulator is behind pan on drivers side

TH350, modulator is behind pan on pass side.

TH400 modulator is forward of pan on pass aide, usually visible from under hood...

Re: How to identify auto tranny type?
 

th350 has detent cable on drivers side of carb. th400 has electric kickdown switch on throttle pedal inside cab