the back of my last 4l60e had 6 bolts to the adapter. i had to take them out many times

 

soooo, no one really knows then? i guess i will just get a tranny and see if it fits.

 

Hey Parish, try contacting Advance Adapters like OOSilverado mentioned. They build adapters to mate different tranny/engine/x-case combos, but are pretty expensive. They should have someone there that knows. Hell, they even sell over priced LS1 engines there now.

ADVANCE ADAPTERS

Also, if they use the same x-case, but different spline counts you might could swap out the input shaft on the x-case to the larger unit for cheaper than a new case. At least I know you can do that on NP-235's as long as the bolt pattern is the same.

Just my .02

 

Oh yeah, and these tranny builders that build 4L80E's ought to be able to tell you what the bolt pattern and spline count is. All they would have to do is walk out into their shop and look.

 

Parish...I'm not sure if this will help or not, but here goes:

from http://www.offroaddesign.com/catalog/doubler.htm

GM 4L80E 4 speed Automatic transmission:
The 4L80 is similar to the TH400. We are not familiar enough with the 4L80 to know all the output options but the most commonly available output is the 2.5" stickout 32 spline shaft shaft that was used with various aluminum transfer cases. This case uses a 2.5" adapter and is mated to the NP203 by using the factory output shaft, adapter housing and a 32 spline input in the NP203. The front face of the 203 will need to be drilled to the GM round bolt pattern to allow it to bolt to the factory 4L80 adapter housing.

GM TH700 R4 / 4L60E Automatic Transmission
The TH700 has the same bolt pattern on the back of the transmission as the TH350 and uses a 27 spline output shaft. Since the TH700 only came with the NP208 or later alum t-cases, it's shaft stickout is a little over 2" in factory form. One difference to be aware of is that the TH700 uses 4 metric bolts to secure the adapter to the transmission case.
There are two ways to bolt to the NP203. They are very similar to the TH350 mounting mentioned above.
1: replace the output shaft in the TH700 with an aftermarket output that sticks out of the case by about 7/8". This makes the output identical to the TH350 and you use a TH350 version NP203 with the 27 spline input and a TH350 to NP203 factory 1" thick adapter plate. This is the shortest method. The output shaft cost is $160 and it is available from ORD.

2: use the factory TH700 output shaft and the factory TH700 to NP208 adapter housing with a TH350 version NP203. You will have to re-drill and tap holes in the NP203 gearbox to be able to bolt it to the original NP208 adapter housing. You may also have to do minor machine work on the input bearing retainer on the NP203.

 

I know for sure that the output shaft on the 60 will not be the same as the one in the 80. So at the very least you will have to change the input shaft on your current t-case in order to fit the 4L80.


Yelo, so you are saying that every chevy 4x4 uses the same transfer case from 1500-3500?

 

i am not exactly doubting you, just looking for a little more conformation. i know the 2wd output shafts are diferent between the 60 and the 80. i know the 1500 and the non HD2500 list the same transfer case, it is because the 1500 with the 60 and the non HD2500 with 80 both list the same transfercase that i think they may have the same output shaft.

 

Thats wierd that they have the same part number.

do you know the part numbers for the transfercases??

 

ok girls, i will have an answer to this question prety soon, i have parts on the way.

 

what did you end up getting? a 4L80E with t-case??