I purchased a 231 out of a wrangler(square headlight era) with a 23 spline input that is short. I have a tf 904 to install it to but that needs the long input. I couldn't call anyone because none of the adapter places I deal with are open on the weekends. I know the difference in length is .9 of an inch and it seems to make good contact on the shaft with the short input so all I could see the extra length being for is to seal the rear of the tranny. I have an old 231 (85 or 86) with the long input but a different cut on the gear. If I took the length I need off that shaft and slid that on the trans shaft first as a bushing would that be ok. I have access to a lathe so it can be cut accurate. I might be getting carried away becuse the input might be cheap but I can't find out till tomorrow and this is bothering me

The problem is your short input shaft (NP231) will not have enough length to grab the seal in the adapter between the trans/T-case, thus will dump ATF all over and make big messes and make you mad (BTDT).

If you dont change to the longer input, here is what you need:

http://www.teraflex.biz/cf/cat/images/179.jpg

TeraFlex sells it under this part number:TL621

Works great to slove this problem.

Awesome thanks very much. I'll call them tommorrow

Clarification -- you have a TF904 with a long OUTPUT shaft, and a 231 with a short INPUT (female) receptacle, right?

If so, cut output to a correct length, check the tolerance, slap on some RTV and bolt'em up!

Clarification -- you have a TF904 with a long OUTPUT shaft, and a 231 with a short INPUT (female) receptacle, right?

If so, cut output to a correct length, check the tolerance, slap on some RTV and bolt'em up!

So how does this affect the length of the adapter (where the seal seats)?