[gnob]

t case mounts, tech tid bit

i just wanted to show some pics and explain potential problems with t case mount differences. what i found is there are at least three different t case mounts, for manual trans of course, i have to assume 1st, 2nd and 3rd gen trucks. but there is the possibility, it could be 79-80 break to 81-88 and 89 up. anyone that knows for sure the info would be helpful.
anyway what i found is this, the 79-80 style has the big center lug thing, offset from center when compared to the other two mounts. this will not allow it to mount up on a later style cross member and/or aftermarket crossmembers. the 2nd and 3rd gen seem to mount up pretty much the same. i also found that the 3rd gen mount is wider front to back with more rubber, so probably better support, and of course should be most sought after. anyway here are a couple pics of the mounts and also of my new budbuilt and duals.

 

[gnob]

here you can see the offset i am talking about, this is the 3rd gen on the left and 79/80 on the right.

 

[gnob]

this is showing the difference in rubber

 

[gnob]

pic of my budbuilt cross, this is to mount duals into a 79 with a w56 trans, bud did a super trick job, especially for a one off application.

 

[gnob]

another

 

[gnob]

mmmmm billet...

 

[Raptorman57]

I do see the difference.One has ears on one side with a little more rubber. This one might be a better mount. But from the way I'm looking at it they look like they will both work. Looks like the big center lug is still centered with the 4 bolt holes that bolt to the transfer case. One just has the ears on one side. Maybe I am looking at it wrong,if so please explain

 

[gnob]

the difference is really not that much, but it is enought to keep it from mounting up right, its like 1/4" off or so.
the pics are hard to see the difference i guess but it is there

 

[85TrailToy]

I think I had one of those offset ones because I had to grind the SOB to make it fit. I tried to get a new one from the local parts stores because I thought mine was squashed but they kept coming up with the wrong parts.

 

[Cracker]

The mount will bolt in, but it will pull on the rubber in a lateral motion, in the front to rear axis. It will eventually pull the rubber away from the plates.
Also, the large round bolt head will rub in the xmember/skidplate hole.
IIRC, 87 was when they widened the mount. This later mount is the one you should get as a replacement.

 

[Cracker]

There are 4 different tcase mounts for 1st & 2nd gen P/U & 1st gen 4-runners.

79-83 RN37, 38, 47, 48 PN 12371-38020 *I would guess this is the one with the offset bolt pattern to large center bolt.

84-86 RN6# PN 12371-35020

87-8903 RN6# PN 12371-35050 *I think this is the wide mount

84-88 RN5#, 7# PN 12371-34030

 

[85TrailToy]

84-86 RN6# PN 12371-35020

87-8903 RN6# PN 12371-35050 *I think this is the wide mount

84-88 RN5#, 7# PN 12371-34030

Are these 3 interchangeable?

 

[85yotatoy]

what is are the bolt sizes for the mount to the tcase i cant find it anyware

 

[yotaismygame]

Mine off my 87 and one i got off a 884runner are both the wide style one.

 

[DWT]

what is are the bolt sizes for the mount to the tcase i cant find it anyware

Good job noobie you obviously searched to have dug up a thread this fawking old. :laughing:


The bolts that hold the mount to the t case are M12x1.25 about 15mm long.

 

[83SHORTYOTA]

edit to this post. mount to t-case bolt size is an M10x1.25...just found this out the other day. and the ones you find at most hardware stores will have a 17mm head instead of a 14mm like the stock bolts.

 

[SeaBass44]

edit to this post. mount to t-case bolt size is an M10x1.25...just found this out the other day. and the ones you find at most hardware stores will have a 17mm head instead of a 14mm like the stock bolts.

you forgot length

 

[DWT]

you forgot length

So did God when he designed my peeter... :laughing:



Sucks when you find an old post where you gave out bad info later... Fawking 'tarded me cornfusing M12 and M10... :homer:

 

[83SHORTYOTA]

the ones i got were 20mm...they worked fine

 

[scottapher]

Bump for an old thread.

Im putting in my skid for my duals and was wondering if anyone remembered the thread and size of the bolts that hold the t-case mount to the crossmember? Im going to grab some flushmount allens from Fastenal, and would like to have those numbers for em.