80w90 or 75w140?

[mkbruin]

So... swapping oil into the 30 front, 35 rear, and BA trans.

 

I have heard some of the YJ guys run 75w140 in the BA. Opinions?

 

Also, how would the 30 do with 75w140?

 

Should I just stick with the regular 80w90 in all three?

[91coMANche]

If you're open diff then it really won't make a difference. I like the thicker stuff only so I don't get leaky seals.

[mkbruin]

How about in the BA 10/5?

[whowey]

Do you tow or haul loads alot???

 

If you do.. then 75w-140

 

Big tires.. deep gears??? then 75w-140

 

If your truck is just a curb cruising street queen

80w-90 is fine

 

In the Tranny... I don't like going thicker than necessary due to the possibility of shifter issues in cold weather. synthetic fluids will help alleviate some of that issue, but not completely.

[mkbruin]

I have been using it as a DD for the past few months. Prior to that, its primary function was a tow vehicle for my camper. I will be selling this truck/camper combo to a fellow CC member in the near future, and want to get the truck as prepped as it possibly can be (he will be flying in and making the 1,300 mile drive home)

 

[86ComancheXNate]

I'm planning on changing my rear diff oil and my tranny fluid as well.

 

I have an amc 20 rear with 4.10 gearing and 31" tires. Should I use the 75-140 for my rear diff?

 

I'm new to all this mechanical stuff should I put gear oil in the the transmission when I drain it or should I just put transmission fluid?

[mkbruin]

Trans fluid depends on what you have.

 

AX-15 uses 10w30 motor oil.

BA 10/5 calls for 75w90 (GL-5)

AW4 uses Dexron/Mercon

a904 uses ATF+4

 

use accordingly....

[jpdriver1]

mkbruin == very nice set up, round figures what does the trailer weigh ?

[whowey]

Trans fluid depends on what you have.

 

AX-15 uses 10w30 motor oil.

BA 10/5 calls for 75w90 (GL-5)

AW4 uses Dexron/Mercon

a904 uses ATF+4

 

use accordingly....

 

 

AX-15 properly uses GL-4 gear lubes. Chrysler switched the recommendation to motor oil, due to not wanting to carry(pay for) a proper gear lube for a single transmission type.

[mkbruin]

mkbruin == very nice set up, round figures what does the trailer weigh ?

 

Its a rare molded fiberglass trailer. Total weight is in the ballpark of ~1,700 pounds.