friend of mine and I where talking about my recent SB 3600 sprung DD upgrade and I was whining about the price of the Mopar tranny fluid which is a GL-4. He said he changed his oil two years ago and about 80,000 km ago to castrol syntec 75w90 synthetic because the parts guy said gl-5 and gl-4 where the same . What kind of damage do you think he has done the tranny seems to be running fine he as changed it out now to the mopar spec.what do you guys think?

Maybe a bit of prolong transmission additve to help extend its life or are the brass syncros already half shot?

J

 

I e-MAILed LUCAS oil and inquired about using LUCAS Synthetic 75W-90 gear oil in my NV4500. (Synchros in my tranny are NOT brass) But, I have Kevlar facing.

They also recommended adding 25% LUCAS PURE SYNTHETIC OIL STABILIZER which I did.

Also, I replaced differential lube with LUCAS SYNTHETIC 75W-90 GEAR OIL + four (4) oz of MOPAR friction improver.

The transmission seems to shift better and is not sticky going into 5th and reverse as it previously was.

I believe in the near future that we will only be able to buy GL-5 gear oil. GL-4 gear oil will go the way of hi sulphur diesel fuel...

 

how do you know the are kevlar? or did you have it rebuilt at one time.

 

How I know they are not brass is I removed the inspection plate on the side of the transmission and with a light and a mirror, looked at the synchronizers. If they are not brass, the way I understand it...the other choice is the ones with kevlar facing. And, they are definitely not brass.

 

Proof is in the driving. If running fine...probably ok. May show a difference at 2-300,000 KM but that's a long ways off...no?

Note: I would not use Prolong (Clorinated Parrifin) in any vehicle from which I wanted long term mileage! JMO.

RJ

 

I have never heard of an NV4500 application that didn't have Kevlar coated synchros.....no brass in any NV4500 that I'm aware of??