TCase Gear Oil question!

[Arlee]

Refilling my 1984 CJ7 Dana 300 Transfer Case and Dana 30 front diff. Looks like I need a GL4, NOT GL5 gear oil (75w90 or 80w90) to fill both (no Limited Slip additive). (Apparently if it is GL5 rated it has brass corrosive sulfer in it.) I cant seem to find any that isn't also GL5 rated anywhere! Anyone have suggestions on where to find the proper gear oil?

 

[Belizean]

NAPA has Vavoline GL4. I ran a T-4 with Castrol GL5 for almost 1/4 million miles when I had many people saying it would not last. Also the differentials with the Castrol GL5. I run my rebuilt T-176 with GL4 now.

 

[Arlee]

It looks like Valvoline Syncromesh for Manual Transmissions that I used in my T-5 might work as a GL4 gear oil with "roughly 75w-90" weight. Anyone done that in the Dana 300 and front Dana 30 Transmission ? NAPA here doesn't have any GL4.

 

[Manic Mechanic]

Amazon

 

[Arlee]

Red Line MT-90 appears to be a synthetic 75w90 GL4 gear oil! Found some on Amazon...think that will work for Dana 300 transfer and the front Dana 30 differential.

 

[hole]

Napa is where I get mine

 

[Sawjaws]

I just bought GL-4 on Summit Racing as I had the same issue with local places. I'm sure they have 75W-90 as well. Unless you can't wait, the price is good...

 

[Arlee]

I finally went with Red Line MT-90 75w-90 GL4 gear oil for Dana 300 xfer, and valvoline syncromesh (GL4) for the T-5 .

 

[Arlee]

FYI...the shop I had refresh the T-5 and Dana 300 recommended "a good synthetic 75w-90 gear oil" for the DANA300, and "regular 10W-30 motor oil" for the T-5. I told him I was planning to use Valvoline Syncromesh and he said that would work fine, but probably unnecessary, overboard and expensive. So I errd on the side of overboard for my fresh tranny!