Differential and Transfer Case Fluid Change- My Observations

[OnTheReel]

Definitely don’t want to run 75w90 in the rear diff. It takes a beating and needs the cushion. If you’re pressed for time get some Valvoline 75w140 from Autozone. Comes in the same squeeze bags too.

 

[evillrdnikon]

That guy at the $tealership doesn't know what he's talking about, hate to say. We do not have LSDs, we have a locker. No additive required.

I don't believe it will hurt anything being in there, but it is definitely not required and provides no benefits.

I don’t disagree with you. I had a 2019 ram 1500 limited before I sold it and got my TRX. That 2019 required the LSD additive. Whatever, $21 cheap insurance if I ever have to show Proof of proper maintenance(if that would even be acceptable). I’m at 30k miles right now. I perform this maintenance again at 60k miles or maybe 45k pending how much I beat up this truck. Hunting season is around the corner and I am planning I saving my miles for traveling to Az for quail or Utah for chukar/pheasant. I used to use my truck as a daily but I was able to get my 2002 Mazda b2300 back and use that as a daily! (Hell yea!). Anyway… will definitely look at amsoil and ravenol for my next go around! Also credit to the first post for recommending the squeeze bags. I just realized that was recommended before I posted my experience.

 

[Rockin98]

Amsoil redtop works fp

I may switch the amsoil for the front and rear. I see folks using ravenol on here but I’ve never had any experience with it. I’ve also heard the red bag amsoil for the transfer case but idk. I’ll research it in about 30k miles from now. Thanks

Yes you can ise red top amsoil for Tcase.
Changed mine at 501 miles no issues at all.
Zero slip.
I also did axles along with transmission which is blue top.
Super smooth shifts and zero slip.

 

[Two]

Hudrolic tractor oil is a type of atf without the red dye. Usually a 10-20w
The lower oil has a better chance of not foaming at high rate of flow speed.

The older vehicles say a 205 t case from the 70's used 75w gear oil because they where a direct gear drive tcase.

Tractor hydraulic fluid comes in many different viscosities, it's AW followed by a number. AW 32, for example, is equivalent to 10 weight motor oil.

Was a bit surprised when finding out the the NP205 in my '91 Chevy called for ATF. Promptly drained it and put gear oil in it.

 

[saturnfire]

I have used a similar hand pump tool in my other vehicles like this :

https://www.amazon.com/dp/B07DTS8N7P

Also used the Valvoline Gear-Oil: https://www.walmart.com/ip/Valvoline-Full-Synthetic-75W140-Gear-Oil-1-Gallon/408175670

 

[jazico]

Does this look right? For front diff spec calls for 75w-85 I think, but from what I can gather in this thread, most are using 75w-90

 

[ONEMEANTRX]

View attachment 152293

Does this look right? For front diff spec calls for 75w-85 I think, but from what I can gather in this thread, most are using 75w-90

If you really want you can run the 75w 85 they just made it for these newer trucks I picked some up but ran 75w 90 in my last trx no issue
just showing you they make it now

 

[jazico]

If you really want you can run the 75w 85 they just made it for these newer trucks I picked some up but ran 75w 90 in my last trx no issue
just showing you they make it now

Yeah I saw that, I wasn't sure what the difference (if any) would be.

 

[OnTheReel]

75w85 only exists to squeeze out an extra teeny tiny bit of fuel economy. Kind of ridiculous when you look at the TRX, but they just carried the spec over from the regular 1500s. I have 75w90 up there currently. Little extra viscosity never hurt anything.

 

[jazico]

Just tackled this myself. Used your guide as reference as well as the actual service information. One area that was interesting was your assessments of how much each took. So here are actual capacities per the service information:

Front Diff - 2.32 pints of 75w/80. I used the amsoil severe gear 75w/90 like you and it took one quart and a bit more
Rear Diff - 5.03 pints 75w/140. I used the 75/140 amsoil here as well and it took just about exactly a 2.5 qts
Transfer case -3.8 pints of Mobil Fluid LT. I differed here and went with Amsoil ATF. They put in writing it meets the specs of the 68049954AA the service info calls for so I'm trying it out. It took just about exactly the 2qts. Maybe you needed the 3 because the hard bottle prevented fully emptying the container, but otherwise there should be no reason it takes any more than 2qts.

Specified torque values:
F Diff drain/fill plugs: 26 ft/lbs
R diff plugs: 20 ft/lbs
T Case: 18 ft/lbs

I only had 1 set of ramps and wanted to stay level so I did it on the ground. Doable, but I'm a bit more sore than necessary.

I also found no extension worked best on the t case for me and just going in front of the exhaust vs using an extension to go from behind it. I was able to do this for both plugs.

How's the tcase holding up with Amsoil in it?

 

[FaTdragon]

How's the tcase holding up with Amsoil in it?

I just changed the front and rear diffs and used amsoil. I used AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid in the transfer case, i fill like I should have used oem instead. Can you guys chime in on this please.

 

[Rockin98]

I just changed the front and rear diffs and used amsoil. I used AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid in the transfer case, i fill like I should have used oem instead. Can you guys chime in on this please.

As long as its redtop you will be fine.
Signature series is thinner with longer life.
Would just change early when time comes.