JFAComanche6 Posted March 21, 2013 Share Posted March 21, 2013 If I have a CAD Dana 30, will the oil pump in my NP 231 t-case pump any oil while it's in 2wd? I wanna lock my CAD and I'm just wondering if I lock it, will my case leak less? It has a crack right on the bottom of the casing covered by JB weld by the PO, and If I can make it leak any slower that would be nice. Trust me, I wanna replace it, but not for what anyone will sell one for around here. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 21, 2013 Share Posted March 21, 2013 You're going to put enough stress on the transfercase by locking the CAD that that crack is going to turn into a cracked in half transfercase. Link to comment Share on other sites More sharing options...
Mountain Dude Posted March 21, 2013 Share Posted March 21, 2013 The oil pump on an NP231 is driven by the rear output shaft, so if the truck is moving oil is pumping, even with the t-case in neutral. Link to comment Share on other sites More sharing options...
JFAComanche6 Posted March 21, 2013 Author Share Posted March 21, 2013 You're going to put enough stress on the transfercase by locking the CAD that that crack is going to turn into a cracked in half transfercase. Then I guess it is time to find a spare. Thanks for the info. Link to comment Share on other sites More sharing options...
Mountain Dude Posted March 21, 2013 Share Posted March 21, 2013 is it the front half or the rear half (or both) that is cracked? Link to comment Share on other sites More sharing options...
JFAComanche6 Posted March 21, 2013 Author Share Posted March 21, 2013 I believe its the rear. The JB weld held fluid great until I got the truck buried in my friend's lake (long story) but I've never seen the crack. It could be a leaky gasket, but it leaks a lot in that one spot and all the JB weld is on the rear half of the case. Link to comment Share on other sites More sharing options...
Mountain Dude Posted March 21, 2013 Share Posted March 21, 2013 Well, if its on the rear, look for a 231C out of a late 80's early 90's S-10 / S15. The rear case halves are identical and you will also get the 6 gear planetary reduction and wider front drive chain as a bonus. I posted a description for the swap in the DIY forum. Link to comment Share on other sites More sharing options...
mvusse Posted March 21, 2013 Share Posted March 21, 2013 Are you sure the 231C has a wider chain? I know a 241C does, as does the 231D HD. Link to comment Share on other sites More sharing options...
Mountain Dude Posted March 21, 2013 Share Posted March 21, 2013 The one I used from an 89 S-10 did http://comancheclub.com/topic/35760-np231j-t-case-upgrade/ Link to comment Share on other sites More sharing options...
87manche1 Posted March 22, 2013 Share Posted March 22, 2013 231c are wide chains between 4 or 6 planetary tho depending on who u ask Link to comment Share on other sites More sharing options...
JFAComanche6 Posted March 22, 2013 Author Share Posted March 22, 2013 Well, if its on the rear, look for a 231C out of a late 80's early 90's S-10 / S15. The rear case halves are identical and you will also get the 6 gear planetary reduction and wider front drive chain as a bonus. I posted a description for the swap in the DIY forum. And the 231C will bolt right in? Link to comment Share on other sites More sharing options...
64 Cheyenne Posted March 22, 2013 Share Posted March 22, 2013 Just the rear case half. Means you have to split the cases, swap parts. Link to comment Share on other sites More sharing options...
Mountain Dude Posted March 22, 2013 Share Posted March 22, 2013 the 231C case has a 5 bolt mounting flange verses the Jeep 6 bolt one. Swapping internals is relatively easy and straight forward. If you are halfway mechanically inclined, you can probably do it...if you are unsure, there is probably another Comanche Club member near you who would be willing to help or provide guidance while you tackle the job. Link to comment Share on other sites More sharing options...
JFAComanche6 Posted March 22, 2013 Author Share Posted March 22, 2013 Sounds like a good learning experience, maybe I'll get another good case and work it out someday :thumbsup: Thanks for the info though! Link to comment Share on other sites More sharing options...
Mountain Dude Posted March 22, 2013 Share Posted March 22, 2013 You're welcome! Link to comment Share on other sites More sharing options...
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