Great Lakes 4x4. The largest offroad forum in the Midwest banner

1 - 15 of 15 Posts

·
Premium Member
Joined
·
965 Posts
Discussion Starter #1
Since doing my 5.3L/4L60e swap a transfer case upgrade has been on my mind. It says on the Novak site that the NP231 is “well mated to V8 power”, but I know that 5.13 gears, 35” tires and difficult terrain can make that statement questionable.

I read on just about every Jeep forum that all you have to do is find a 231C for 50 bucks on Craig’s List to get the wide chain and gears, and then find a 241D HD and grab the 6 planetary gear-set. Well, I looked most every day for about 6 months. I never saw a 231C for less than $150 and I never saw a 241D HD at all. I thought I was just going to have to run my 231J until it broke then go up to a 241OR or even a Altas when the time came.

Somehow I came across a guy on Ebay that was selling the t-case parts and I contacted him. http://stores.ebay.com/powertrain-parts-plus/Transfer-case-parts-/_i.html?_fsub=5303410&_sid=369570213&_trksid=p4634.c0.m322
He said he would sell me a slightly used, but good condition wide chain and gears, plus a 6 planetary gear-set for $142 shipped. I was surprised and didn’t think it could really be true. I wasn’t having any luck with my original plan so I decided to take a gamble and try it. The parts arrived quickly and were indeed in good condition.


The only thing I have ever done to a t-case is installing a couple SYE kits. But, I have done a couple manual transmissions so I figured it couldn’t be worse than that and yanked my t-case out and started to disassemble it.

Tail cone off.


Back half of case off.


Pulled this out of t-case.


231J three planetary gear-set.


Remove front cover.
 

·
Premium Member
Joined
·
965 Posts
Discussion Starter #2
Pull the input gear and planetary out.


Reassemble input gear with new six planetary gear-set.


Here is the difference in the size of the chains.


Difference in the gears.


Pop this thing off the output gear.


And this.


So it looks like this.


241 gear on the right has roller bearing inside you need to knock out.


Put it back together,


That’s it! Reinstall the t-case and enjoy your new found piece of mind.

It took me a total of about 3 hours because I was taking the pics and trying to remember the steps.
 

·
Little Member
Joined
·
23,794 Posts
Nice tutorial. I assume the 231 sye kit fits Jeep and S-10 cases. If that's so, I'll get a 231 Chevy ready for my XJ for when the time comes.
 

·
Sketchy, Son....
Joined
·
2,535 Posts
I did this exact setup on my ZJ's T Case about 6 months ago. Havent had a problem yet, and I have been thrashing the shit out of it.
 

·
Registered
Joined
·
2,293 Posts
I did this exact setup on my ZJ's T Case about 6 months ago. Havent had a problem yet, and I have been thrashing the shit out of it.
then why didnt you post on my tech thread ass :finger: :teehee:

what size socket is used for the yoke on the front of the case??
 

·
Weapon K
Joined
·
1,460 Posts
Nice documentation John D!


I assume the 231 sye kit fits Jeep and S-10 cases. If that's so, I'll get a 231 Chevy ready for my XJ for when the time comes.
I believe the Jeep and Chevy 231's are clocked differently, so if you're using a Jeep trans just toss the Chevy guts into the Jeep 231 then add your SYE. :thumb:
 

·
Premium Member
Joined
·
965 Posts
Discussion Starter #10
Nice documentation John D!

I believe the Jeep and Chevy 231's are clocked differently, so if you're using a Jeep trans just toss the Chevy guts into the Jeep 231 then add your SYE. :thumb:
Thanks.

The 231C (Chevy) has a 4 planetary gearset.

I got the chain and gears from the 231C and the 6 planetary gearset from a 241D.
 

·
Premium Member
Joined
·
4,982 Posts
i did a sye on a 231c not that long ago and it had a 6 planetary set
does that make sense?
 

·
Registered
Joined
·
218 Posts
dhd

the dhd planet has a pto gear on it also and might not fit into your case but I have the standard 6 pin planets...if you are interested I can be reached at 612-309-3999
 

·
Yooper In Training
Joined
·
7,057 Posts
FYI, for anyone searching I believe the planetary and input assemblies on pretty much all 231, 241, and 208 t-cases are available. Maybe others too, I don't recall. Back when I was doing a 231-300 doubler I had a 241C that I took the 6 pinion planetary and 27 spline input gear out of and put into my cut 231J case to bolt behind a 700R4 trans. Lots of good interchangeability between these cases.
 

·
Registered
Joined
·
447 Posts
I've been running a 231C in my 350 powered XJ on 42's for years without issue, although I do have a spare for when it does let go.
Also FYI, the more geared-down your axles are, the less stress your trans and t-case have, as it is transferred more to your axles shafts which are down-stream of the gear reduction.
 
1 - 15 of 15 Posts
Top