Post by 1tonflattie on Oct 22, 2008 22:20:40 GMT -5
Many of you may or may not be aware that Jeeps are not the only vehicles to use the NP231 transfer case. Chevy S10s and some Dodges use them as well. My old trail rig was an 89 S10 and I ran the 231 for years with no issues. I installed a JB Conversions SYE in my 231C case and used a speed sensor from a Dana 300 with a mechanical speedometer, because at the time there was not an chevy version of the SYE, and the only difference is the chevy uses a smaller speedo sensor.
The other differences between the Jeep 231 and the Chevy 231 is the Chevy uses a 27 spline input with a six gear planetary (for low range reduction) while Jeep versions use a 21 or 23 spline input (4 or 6 cylinder repectively) and a 3 gear planetary. There are a few more differences which I will show here.
The purpose of this writeup is to outline some upgrades I did to my friends 231J case for his cherokee, using parts from my old 231C case.
Heres the chain that drive the front output, the chevy version is wider (left) than the cherokee (right)
and of course the gear on the front output shaft is wider on the chevy (right), altho the spine count and diameter at the yoke end is the same. meaning you can use the same yoke
heres a pick of the stock jeep shaft vs the JB conversions shaft with 32 spline output. The s10 gear cluster is already installed on the JB conversions shaft. It uses a wider gear to drive the front output chain as well; and if you look closely there is also a syncro ring to make it shift smoother, that is absent on the jeep version
everything installed in the jeep case
JB conversions Tail cone (green) vs stock jeep. The JB conversions uses a bigger bearing
Putting it together
one more fine detail. Chrysler uses plugs that take a 10mm allen to loosen. The chevy uses a plug that takes a 1 5/16" socket or any large pliers that are more commonly fround in a trail tool box then a 10mm allen, altho you can pick what you'd rather have. Pete picked the S10 plugs
I still have more to look at, I want to figure out if it is possible to swap in the chevy 6 gear planetary without the 27 spline input, so it could be used in a jeep
The other differences between the Jeep 231 and the Chevy 231 is the Chevy uses a 27 spline input with a six gear planetary (for low range reduction) while Jeep versions use a 21 or 23 spline input (4 or 6 cylinder repectively) and a 3 gear planetary. There are a few more differences which I will show here.
The purpose of this writeup is to outline some upgrades I did to my friends 231J case for his cherokee, using parts from my old 231C case.
Heres the chain that drive the front output, the chevy version is wider (left) than the cherokee (right)
and of course the gear on the front output shaft is wider on the chevy (right), altho the spine count and diameter at the yoke end is the same. meaning you can use the same yoke
heres a pick of the stock jeep shaft vs the JB conversions shaft with 32 spline output. The s10 gear cluster is already installed on the JB conversions shaft. It uses a wider gear to drive the front output chain as well; and if you look closely there is also a syncro ring to make it shift smoother, that is absent on the jeep version
everything installed in the jeep case
JB conversions Tail cone (green) vs stock jeep. The JB conversions uses a bigger bearing
Putting it together
one more fine detail. Chrysler uses plugs that take a 10mm allen to loosen. The chevy uses a plug that takes a 1 5/16" socket or any large pliers that are more commonly fround in a trail tool box then a 10mm allen, altho you can pick what you'd rather have. Pete picked the S10 plugs
I still have more to look at, I want to figure out if it is possible to swap in the chevy 6 gear planetary without the 27 spline input, so it could be used in a jeep
