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MOTOR OIL recommended for NP231 T-case.....

XpedientJ

XpedientJ

NAXJA Forum User
Location
MA
I happened across THIS info. on the Novak site:

http://www.novak-adapt.com/knowledge/transfer-cases/np231

Particularly, THIS excerpt:

"ATF is the factory recommended fluid, however many individuals have chosen to run a straight 30 weight oil or 5W30 in a mineral or synthetic. Our experiences with these and those reported to us by our customers indicate positive results in noise reduction and wear resistance."
 
My January 2002 issue of Transmission Digest backs this up, although only 5w30 synthetic engine oil is recommended over ATF to eliminate "misting," a slow loss of lubricant through the vent.

Both New Process 231 and 242 transfer cases can safely use 5w30 synthetic engine oil. Improved durability is noted in this study as well.

I have used 10w30 Synthetic engine oil in my NP-242 for about 7 years, and I can report exceptional performance as well as durability. It shifts in and out of 4WD like warm butter, often so quietly that it makes no noise at all. I change the fluid yearly along with a scheduled LOF, and it always looks clean. 10w30 is already on my shelf, so no special lubricant is needed.

I formerly used Dex/Merc ATF. It was noisy and shifting was notchy and difficult. Changing to 10w30 synthetic engine oil was a huge improvement.

I am sure many will disagree with this article and my own experience. To each his own.
 
If I remember correctly its also suggested to use 10w30 synthetic in the AX-15, I did for about a year, wasn't pretty coming out, switched to redline MTL no issues since, wonder if redline makes any oil in the right viscosity for the Transfer case?
 
I use B&M trick Shift ATF. TC is quiet and shifts smoothly. NV242J

I tried various motor oils and saw no real improvement. I check my TC fluid level at engine oil change and top off as required - usually doesn't need it. Then replace the fluid at trans drain/refill.
 
sinat01 said:
How often do you guys change the trans/transfer case oil?
Click to expand...

Yearly, along with the transmission fluid, brake fluid, differential lubricant, coolant and power steering fluid, if you want it to last forever. Most could not care less. I plan to drive my XJ another 25-30 years, so these fluids get changed yearly. Oil changes every 3 months of course. And I use the best lubricants money can buy. At 186k, it still looks and runs like brand new.

I've been approached by people at gas stations, offering me $10,000 dollars on the spot for my Cherokee.

Bite me: she ain't for sale.
 
Last edited:
Jesse_Hallum said:
Yearly, along with the transmission fluid, brake fluid, coolant and power steering fluid, if you want it to last forever. Most could not care less. I plan to drive my XJ another 25-30 years, so fluids get changed yearly.
Click to expand...

Jesse, thanks for bringing up the other fluids.
Brake fluid, power steering fluid and coolant are sorely neglected maintenance items.
 
Hmm... good to know. Jesse, did that Transmission Digest make any recommendation as to brand of 5W30? If I just dump the cheap Dollar General synthetic 5W30 in, will it blow up my T-case? (I kid, of course.) I need to change out my trans and T-case fluids soon here anyways.
 
JeepNoob said:
Hmm... good to know. Jesse, did that Transmission Digest make any recommendation as to brand of 5W30? If I just dump the cheap Dollar General synthetic 5W30 in, will it blow up my T-case? (I kid, of course.) I need to change out my trans and T-case fluids soon here anyways.
Click to expand...

Kid if you want, but if it meets the spec, it meets the spec, regardless of who's sticker is on the bottle.
 
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