THM125C automatic transmission coding? What final drive ratio does it have? (Page 2/2)
olejoedad AUG 03, 07:43 AM
It should fit, but gear ratio may be different.
cebix AUG 04, 07:56 AM
Got a better look at the transaxle and there are some differences.

The dipstick along with the tube is twice as long.
The upper vent tube is just a tube going nowhere where as in the Fiero there was a little cap there. Should I put some kind of one way valve on it or a filter?

[This message has been edited by cebix (edited 08-04-2019).]

olejoedad AUG 04, 02:57 PM
If you already have a TH125C, you should be able to use the dipstick and tube from it.
cebix AUG 06, 02:03 PM
Anybody has any ideas about these differences? I attach a photo of an original THM125C from a Fiero and the differences in my Grand Am transaxle.

1. The electrical connector is 180 degrees out of the original one. Is that a problem?
2. The cooling lines - the upper original cap is just a tube here. The lower ones where they go to the radiator - one is blocked off. What should I do about this? Is this original?

Here's an original:



And here's my Grand Am one:





Thanks.

[This message has been edited by cebix (edited 08-06-2019).]

cebix AUG 07, 03:50 AM
I found these bulletins showing the differences. Does it really matter in this situation? Can I leave the upper tube just in the air? Parts 404, 405.

Fiero:



Grand Am:

[This message has been edited by cebix (edited 08-07-2019).]

olejoedad AUG 07, 06:28 AM
The blocked off cooling line is just pinched off when it was cut.
Your Fiero cooling lines should transfer over.
The NSS (Neutral Safety Switch) and select arm will transfer over from the Fiero.
If you can change the vent tube, go for it,if not, I don't think it would be a problem.
cebix AUG 07, 07:32 AM
Unfortunately I don't have the NSS and the gear selector arm from my original transmission. Won't these found on the Grand Am transaxle bolt up to my original cable?

[This message has been edited by cebix (edited 08-07-2019).]

olejoedad AUG 07, 09:55 AM
I don't know, as I am not familiar with the way the Grand Am shifter is set up.

Perhaps someone with more knowledge will chime in.
cebix OCT 07, 07:46 AM
A little update. Cables attach good but the selector is backwards, totally messed up. D is P, N is R, R is N, P is D and you can't go forward anymore, you get the idea.

Can I somehow modify this to work correctly in the Fiero? I don't have my original gear selector arm and NSS and not sure I can buy one locally.

Thanks.

[This message has been edited by cebix (edited 10-07-2019).]

cebix OCT 07, 02:11 PM
Alternatively could anybody post some pics of their automatic transaxle near the NSS and the selector arm for reference? Would help me alot in figuring this out. Many thanks