The only oil approved for use by Chrysler is Syntorq® 75w85w synthetic oil and seams it is only available at a Chrysler or GM dealership:confused013: You can try other 75w85w synthetic if you can find it, but i wouldn't risk it.

 

I used to run Redline MTL (70w80) in my old '99 with the NV4500. Less than half the price of the Syntorque stuff and probably better quality. It's a GL-4 Rated oil which is hard to find (many of the oils on the shelves at the local stores are GL-5). I ran it for about 75,000 miles in my '99 and noticed much improved shifting and never had any problems right up till I sold it. Saw the new owner the other day and he's put another 50,000 on since he bought it and has had no problems either (hasn't changed the tranny oil).

link- Red Line Synthetic Oil - Gear Oil for Manual Transmissions - MTL 70W80 GL-4 Gear Oil

You can go to the website and look for local dealers if there are any in your area (FYI, most Autozones don't carry the stuff but can order it) or just order it from them directly.

 

My recommendation...AMSOIL Synthetic Manual Transmission and Transaxle Gear Lube (MTG)

 

I used an equivalent from Amsoil.

AMSOIL - Synthetic Manual Transmission and Transaxle Gear Lube 75W-90 (MTG)

 

Does the trany hold 4 or 5 quarts. i dont remember

 

i lookd at both might go with amsoil.

 

fyi. this is my first post on this forum. i have a 96 3500 w/ nv4500. i am replacing the trans for the 5th or 6th time. researched what is the fluid to use and most info says chrysler/dodge special high dollar stuff or castrol syntorq 75/85 synthetic. cant even find the castrol. so i go to the stealership (saw this spelling from another member and i like it!) and asked them if they had it and how much. guy looks it up on the computer and says engineering dept and some other dept at dodge changed the recommendation to atf plus 4. i asked if that was synthetic and he said no. SO WHAT HAS CHANGED IN THESE TRANSMISSIONS THAT DONT HOLD UP? i guess i will just go with amsoil and hope the rebuilder welds the fifth gear nut on right. feel free to comment. learn something new everyday.

 

ATF plus 4 is what I put in mine years ago, it was recommended then.

 

They were not designed for atf and atf+4 is synthetic. There is a shop called Bluementhal out of Oklahoma City that makes the correct fluid for our old transmissions.

 

i guess i will put what ever the rebuild shop recommends since they cover it. i pull trailers often with this truck and drive from pa to florida few times a year, but go to atlanta every month. 439000 on the od but at least 6 rebuilt trannys , mostly because of 5th gear. i dont feel i pull that much weight. got a powerstroke 7.3 but at 180000, it needs a tranny rebuild. the dodge is cheaper to fix..

 

You had it rebuilt every time 5th came off? I drained my Bluementhal fluid, put 5th back on and refilled with the old fluid.

 

i think one time my old mechanic fixed it in his shop, but after that i had rebuilt ones put in it. they were w arrenteed. i never did mechanic work on my trucks until recently when business dropped off and i felt some mechanics were taking advantage of me. i do pull and replace my tranneys. havent tried to do internal work on a motor or trans yet. also, people talk about metal debris getting in the bearings, etc. so i just get rebuilt. i love youtube!

 

The 5th gear but is a stupid easy fix. Fixed mine on the pad in front of my garage. Just pried t/c back and made a long socket welded to a pipe

 

The 5th gear fix isnt a cure all . Its great it may not fall off , But the design is the real probl with no support whatsoever in that area .