hye guys um I want to change my tranny fluid in my 6 speed and i went to my dodge store and was going to get 5 litres of MOPAR 75-90 synthetic cuz thats what he said to put in... BUT he told me the price and it was 23 dollars canadian for one litre so I told him to go hump his hat and left so I went to a local parts store and bought some 75-90 syntetic for 34 bucks CAN. so I am just wondering if it is allright to run this stuff cuz I think its about time to do it... thanks for the help

 

In a word - no.

With that viscosity range, it's likely that you bought a GL-5 rated gear oil. If you use it in an NV5600 transmission, you'll probably damage the "soft" yellow-metal synchronizers over a short period of time - and the NV5600 is infamous for tearing up its synchronizers, so the idea is to baby them along. GL-5 is formulated for the stress and shock of differentials and axles, and has no additive profiles for soft metal.

You need a specially-formulated GL-3/GL-4 lube that can withstand gear stress and protect the sychronizers at the same time. IMO, the best choice is Redline MTL (not MT-90), which is a better oil than what DC carries. Not only does it have superior specifications, but many claim it allows the NV5600 to shift more smoothly. (It did for me.) Others prefer equivalent Royal Purple or Amsoil lubes.

All are synthetic, all are expensive, all are easily available on the web, and probably not available in home town auto parts outlets.

If the synthetic you bought is GL-5, use it to change out your differential lubes.

 

Yup, the sulfur that is in the GL-5 gear oils chemically reacts and wears the synchros.

Tank 66, you can get Redline Mtl at Mopac Racing in Edmonton, Calgary, or Vancoucer. Not sure if they will ship it to you but I see no reason why not. I paid $55 for the MTL in Edmonton.

 

Same as Dr. Evil, Mopac in Edmonton, You could try Grandwest in Toon Town, It would be worth a try seeing that you are closer to Stoon.

 

ok so I have like no mods on this truck so what is in it right now then for tranny oil... cuz the stuff they were going to sell me at dodge was 75-90 synthetic

 

Having modifications makes NO difference whatsoever - what we are trying to tell you is you either have to use the stuff from the dealer or get some Redline MTL. If you dont, you are risking transmission problems.

Does the tranny fluid you bought say GL-4 or GL-5 on it? It should say GL-4.

IMHO, spending a bit more on oil is sure a lot cheaper than tearing down the tranny to replace synchros.

 

Frankly, there are some DC dealerships that push 75w-90 GL-5 on customers as the "proper" lube for the NV5600 - I had one try that on me. If you want it simple and right, go with the recommendation for Redline MTL.

 

Redline MTL. It's like butter!

 

You can also use it in place of hotsauce