GM Cases. - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 09-24-2005, 06:47 PM Thread Starter
 
Join Date: May 2001
Posts: 3,501
Thanks: 0
Thanked 0 Times in 0 Posts
 
GM Cases.

Anyone know what kind of compatibility there is between the GM NP231, the 241, and the Jeep stuff?

I've been thinking about getting a doubler setup, one of the ones that uses an NP231 set of planetaries, the only problem is that its another 7" and my angles are PERFECT right now.. I'd really like to keep them that way.

So I got to thinking, the adapter for the th350-D300 is about 5" long or so.

GM did put 231s and 241s in their trucks right? behind Th350s, and 700R4s.

But what adapters did they use to go from the 4 square bolt pattern to the NP231 pattern (6 bolt circle i think it is)

I've seen lots of pictures where they use a completely flat adapter.

So assuming the cases are identical except for the input gear (23 on jeep, and 27 on the chevy) I could use a Chevy case, bolted straight to the Th350, then use the doubler kit to bolt from the 231 planetary box to the D300.

But this only works if the cases are identical in every shape/form.

anyone know about these two/three?
Infernozx is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 09-24-2005, 07:03 PM
Carpal \'Tunnel
 
wrath's Avatar
 
Join Date: Nov 2001
Location: Waukesha, WI
Posts: 3,323
Thanks: 0
Thanked 1 Time in 1 Post
 
Re: GM Cases.

In order to put a 231 or 241 behind a TH350 you must find a TH350/NP208 adapter. These are actually kind of rare.

You can find 231s, 231HDs, 241s, 241HDs, et cetera behind 700R4s (27 spline). You can find 241s and 241HDs (both in passenger and river side drop) in 32 spline format behind TH400s, 465s, 4L80s, 4500s, et cetera.

I assume you're looking for a driver side drop case. In that particular instance, I'd look for an early 90s 4.3L S10 case or an IFS Chevy case through the mid 90s. Either of these cases will get you 6 pinion gears and a real chain. If you get the 241 you'll get a longer chain and bigger sprockets and better webbing on the case.

You can swap inputs between all of the 231s/241s up through somewhere in the mid 90s I believe. Somewhere around there they changed the pitch of the gears.
wrath is offline  
post #3 of (permalink) Old 09-24-2005, 09:26 PM
 
Join Date: Aug 2000
Posts: 4,282
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: GM Cases.

The gm 231's use a 5 bolt pattern. In my heep i have a gm/jeep bastard child 231. It uses the trans side gm case and the rear output side jeep case with an sye. I can't remember which internals are jeep and which are s10.
Jeeper99xj is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 09-25-2005, 01:17 PM
I Might Just Know What I'm Talking About
 
Randyzzz's Avatar
 
Join Date: Jul 2001
Location: Sisters, Oregon
Posts: 1,988
Thanks: 0
Thanked 1 Time in 1 Post
 
Re: GM Cases.

You can use a GM 203 adapter, which is 3/4" thick. It will have to be redrilled for the 231, a fairly easy task. The main thing is the bearing retainer adapter pilot for the T/C is the same diameter. I have a D300 adapted to a TH350 this way. But, using the planetaries out of a 231 case will still get you a 5-6" doubler.

Here's an old link ...sounds like what you're trying...
http://www.bc4x4.com/tech/bryce/tcase/tcase.cfm
Randyzzz is offline  
post #5 of (permalink) Old 09-25-2005, 05:41 PM Thread Starter
 
Join Date: May 2001
Posts: 3,501
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: GM Cases.

How'd you get the 300 input to be 27 spline for the th350?

I looked into this before buying my Novak setup.. would have been way cheaper/shorter then the stubshaft and 5" of adapter i have now.
Infernozx is offline  
post #6 of (permalink) Old 09-26-2005, 03:36 PM
I Might Just Know What I'm Talking About
 
Randyzzz's Avatar
 
Join Date: Jul 2001
Location: Sisters, Oregon
Posts: 1,988
Thanks: 0
Thanked 1 Time in 1 Post
 
Re: GM Cases.

I changed the input gear...$175.00 from JB Conversions.
http://www.jbconversions.com/
Randyzzz is offline  
post #7 of (permalink) Old 09-26-2005, 04:45 PM Thread Starter
 
Join Date: May 2001
Posts: 3,501
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: GM Cases.

Damn, I wish I had known about that before i went and shelled out for the novak setup [img]/ubbthreads/images/graemlins/frown.gif[/img]
Infernozx is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome