NP T case Question

[SUA SPONTE]

hey guys. An easy fluid question- my haynes book is telling me to put
dextron 2, 3, or mercon AUTOMATIC TRANSMITION fluid in my t- case. Others have told me 80/90 gear lube. What to you all use.

87 amc laredo Man. trans

[Bob Myers]

book says ATF, if you put80/90 weight it'll be too thick and bearing failure is likely to result. So, who's info do you trust more? The manufacturer or someone who is just telling you something to be telling?

[Lonestar]

Use ATF. 80/90 will ruin your chain and pump gears.

[RichP]

Actually I'd use Mobil-1 ATF, makes it shift much smoother, been running it in my 98's 231 for the last 250,000+ miles...reminds me, gotta get off my ass and go change my AX15 tranny and tc fluids...

[Oizarod115]

definitely do not use 75w90 gear oil or anything similar.

a while back my friend rebuilt my np242 and he filled it with gear oil and i trusted him, and didnt ask questions. 10K miles later the oil pump was toast, which causes the chain to stretch rapidly, leavin you with a 92lb paperweight behind your tranny.

the gear oil is too thick to pump thru the case. always refer to the manual or factory service manual or chiltons/haynes when it comes to that stuff. your buddies dunno what theyre talkin about.

i learned to rebuild my own transfer cases after that.

-Tim

[5-90]

For future reference, I've got a listing of fluid recommendations in the Tech section of my website - compiled from various FSM's (I won't use anything else...)

You might want to check there if you have any questions. I haven't gotten them all yet, since I still need to get a few FSMs, but one should be readily able to divine patterns...

5-90