Transfer Case Fluid
 

Hey guys I've noticed some seepage or "congealed" drops of fluid on my t-case. I'm wondering how to check the fluid to make sure it's not leaking too badly. I want to change the fluid anyway but I'd like to know what's dangerous or not.

I remember someone posting a diagram of the t-case/fill plug/drain plug. I believe I found them on my t-case but I'm not positive. They're the two bolts that look like they require a huge allen wrench to remove right?

Lastly what are the fluid recommendations? How much fluid should I use?


regards

I used the M1 gear oil (you could go regular or thicker with the 75W-90 or the 75W-140). It takes around two quarts. The only way to really check would be to take the top plug out and "top off" until it drips out. Honestly, if you are doing that just change it out though. Make sure you could get the top plug out BEFORE taking the bottom plug off to drain. Also, regardless if just topping or changing, you will need to get one of those cheap hand pumps to attach to the gear oil bottle. IIRC, I believe on those I used the end of the 3/8" ratchet with no socket to do the plugs. You could also buy the metal plugs to replace the plastic ones. I would also recommend putting a bit of teflon thread tape (or another type of thread stuff) on when putting them back.

Just changed the Transfer fluid the past weekend. Use a 1/2 rachet without any socket of course. I used permatex thread sealant but you could use just about anything. Two bottles of 75-90 synthetic gear lube will be all you need.

Do yourself and your truck a favor and up-grade to 85W/140 for better wear protection and quieter gears for both the t/case and diffs.

what Disco Mile said.. i did the same about 2 months ago and is is certainly a little less noise.. and the extra wear protection can certainly never hurt.

What mike said. Makes a big difference in the sound level coming from all three and why not have better protection.

is 85-140 available at autozone?

Yup. They have a few to select from. Like Royal Purple. I'm running this in my trans and will use this in my diffs - when I get a chance to change it.
Royal Purple/1 qt. 85W-140 synthetic Max-Gear oil (01303) | Gear Oil | AutoZone.com

You will need 7 qts to do both diffs and the t-case.
I go to Tractor Supply Company and buy it buy the gallon, I use their house brand in 85w-140.

Just curious, do you use synthetic? Assuming that you don't if your buying that stuff by the gallon. Could get mighty expensive if you change it often.

Synthetic...pfffttt...NOT!!!
I will never use full synthetic ever again.
I buy the cheap dino lube and change it once a year as part of my spring maintenance program.

Spike why no synthetic?

And thanks for the replies everyone, it's all been really helpful.

Should I be concerned with the brand? I can get 85w-140 in Coastal and Traveller, Castrol, and Lucas, they didn't have it in Rotella or Royal Purple. Also if I don't go with synthetic does that just mean I have to change it out more often? They don't have many synthetic options at the store.

I used the GM lube with the pleasant grape scent, lol I kid you not. Says it right on the bottle. Have a friend who works at GM so although its not the super gooey stuff, it is free. Just smells like nasty gear oil with a wiff of grape. Lol

Ok well I just got some Castrol 85w-140. Hopefully that will serve me well? How often will I need to change it?

Because when you go off roading/wading and you get water in one of your diffs and you have to drain out $130 of gear lube you feel pretty stupid.

How often should you change full syn gear lube?
I say every 50,000 miles, but I'm sure a lab test would say you could go longer.
As for dino lube, I say every 30,000 miles, again a lab test would say longer.

I change mine once a year, every spring after I go wading, its cheap insurance and it also keeps me intune with my truck.
Thats a good time for a full inspection under the truck.

I'd stick with Syn as that is what is called for. As mentioned if you are going to have the truck under water for extended periods of time and have the chance of getting some water in (would like to see exactly where it would enter for my own knowledge though) and have to change it out, I guess the regular stuff is OK. If you don't plan many river crossings though, I'd still say syn.

Ah I see. Well the thing is that there is no option to order the royal purple 85-140 synthetic online, at least at autozone. Plus none of the stores around my home have it. Am I in danger of anything with regular Castrol 85W-140? The t-case is not something I want to play games with. Just nervous about it i guess.

It does not matter if you use syn or dino, your transfer case does not know the difference. As long as the oil specs match what is required (GL-5 I think) then you are good. Don't over think it....

Now that is not fair! Over thinking things is *exactly* what this forum is about! :)

It's freaking gear oil, not rocket surgery...

When your truck has over 200,000 miles on it the seals are not as tight as they used to be.
I only got water in my diffs once, that was the rear diff and it was because the axle breather was clogged and the pressure would build up inside the diff and cause the front seal to leak.
Wading let water in.
Replaced the axle breather and no more water in the diff.
Any person who wades needs to not only grease their u-joints after wading they also need to check all fluids for water ingress.
But if you never take your truck off road you dont need to worry about it.

x1000!!!

Necro bump....

Is anybody using 85-140 in their transfer case?

I need to change/re-seal mine...

I found some Lucas 85w-140 for 8.99 at advance auto....prob just going to do that.

I use Royal Purple 85w-140 in both diffs and transfer case.

Just put this in my case after resealing the inspection cover.. Still have a little bit of leak which i need to look into, but i swear things are running a tad quieter with the thicker oil :dunno: