Differential and transfer case oil

looking for recommendations on what brand oil y’all like for both your differential and transfer case. I’m looking at changing both this weekend. Also how hard of a project is this for someone who’s not exactly a wrench turning type. Thanks in advance

 

75w90 gear oil, super easy process. There's a drain plug and fill plug on the diffs and t-case. Replacing the crush washers on each of them is smart to do, you can pick those up from the dealer (or online).

Always loosen the fill plug first, you don't want to drain it and then realize the fill plug is stuck on or stripped.

The front diff uses a hex/allen key rather than a normal socket like the t-case and rear diff, make sure you clean the dirt out of the hex before you try loosening them or they will strip on you. Speaking from experience

 

Boom. What he said ^

 

Awesome thank you this will be very helpful! Stupid question tho... use the 75w90 in both the t case and the diffs?

 

Thank you good sir! Any brand preference or just the super tech that Walmart sells?

 

Any regular gear oil will do, just don't use synthetic in the diffs. Regular stuff is better for them.

The manual transmission (if you have one) is where it pays to use the good (expensive) stuff

 

Cool beans. Sadly it’s an automatic so I guess I’ll just have to see what’s on sale!

 

Everyone's got different preferences on brands but honestly if you change it at the regular suggested intervals it really shouldn't matter.

Only time you might want to change up the type of gear oil is if you do a lot of towing, wheeling, extreme cold weather, etc. Otherwise just go by the book

 

Next stupid question.... Why not synthetic?

 

East Coast Gear Supply and other manufacturers all suggest regular dino oil over synthetic, the regular stuff does a better job of not thinning out when it gets really hot like synthetic does. Also regular gear oil separates water from the oil better than synthetic does.

Here's one article on it

https://eastcoastgearsupply.com/ft-2536-ecgs-gear-oil-recommendation.html

 

Are you talking about transmission fluid now? Or still gear oil?

 

He's talking about auto trans fluid

 

Awesome thanks for the article I’ll check it out!

 

That's really just pertaining to gear oil, when it comes to engine oil I think synthetic is the way to go personally. I switched to that awhile ago

 

I always have and always will run synthetic motor oil. Stay posted for all my attempts at doing all this for this weekend. Going to do the diffs, the t case, motor oil , trans fluid and change all my belts and hoses and lastly plugs and wires if it needs it. I just bought the truck and it had 115k so I figured why not do some basic things! Anything else I should do?

 

Differential and transfer case oil
I use redline or Amsoil.

 

I was given a free case of valvoline 80w90 gear oil.... would I harm my rebuilt trans by using that instead of 75w90?

 

Nope! Thats what I ended up putting in mine. As mentioned because walmart sells in the gallon jugs

 

I highly recommend Redline MT90 in the 5 speed.

 

I have been using AMSOIL Severe Gear 75w140 in my E-locker since day one. My experience is the diff runs 10 degrees cooler than 75w90 and the magnetic drain plug has much less particulates with the 75w140.
Personally I think Lucas oils are marketing company, not a cutting edge oil company. I have yet to read a white paper on any Lucas product that performed well. Usually near the bottom.

Here is an interesting read.
https://www.lastgreatroadtrip.com/wp-content/uploads/2010/11/gear-oil-comparison.pdf