Question Transfer case & diff fluid

[VinceJE]

I'm sure this is a debated topic already, but I did some searching and couldn't find too many opinions...

I'm doing a full drivetrain fluid & lube this weekend starting with MerconSP in the tranny. What about the transfer case and diffs? What are the opinions here on the fluids/lubes?

Can I use the MerconSP in the xfer case? (book says use ATF)
I am planning to use RP Max gear in the diffs. The book calls for diffeerent viscosity in rear vs. front. What are the thoughts on this?

Sorry if this is a dead horse I'm trying to beat again. If there is a good thread on it, then just show me the way.

THANKS!!

 

[DaveBen]

Mercon SP is ATF. Use it if you want to. The difference in the two differentials is due to the constant use by the rear diff. Also the Posi in the rear diff. Go with the book says!!!

Dave

 

[VinceJE]

I'm a big fan of RP products.
Does anyone have experience using the RP ATF good in the xfer case and RP Max Gear lube in the diffs?

 

[DaveBen]

Let me make this clear: DO NOT USE ANYTHING EXCEPT MERCON SP in your transmission!!!!! There are NO other options and DO NOT LET ANYBODY TELL YOU SOMETHING ELSE!! Use only Mercon SP.

Dave

 

[MJ Synthetics]

As far as gear lubes I could post a link to a study about gear lubes where RP fail a test in the sequence of tests. There are many good gear oils but I would stay away from RP and Lucas.

 

[SyN PSD]

Vince: If you use your 4wheel drive alot and for extended times? I would pour in a synthetic ATF in your transfer case. They can really see some high temps during long periods of use. If you only use it once and a while and for a short period of time, a regular dino ATF will work fine. [You can use the RP ATF in your transfer case]&[RP gear lubes in your diffs].-->75W-140=Rear 75W-90=Front. {Might have to add a bit of friction modifier-depending on how much your clutches are worn in your Rear Diff].

As for your diffs. I don't like the RP -->JMHO esp their engine oils-->alot of $hitty UOA come back with their engine oils. I really know nothing about their gear oils. If ya want to pour in probably one of the best gear oils? Pour in Redline. Their gear oils are top notch. M1 produces a good gear oil. I'm not bashing RP Gear oils, I'm sure they will hold up well. I've just seen not stellar UOA on their diesel Oils.

I myself use Amsoil. I use my 4wheel drive more then most so this is what I have in my F250.

Front diff--->Amsoil SVT 75W-110
Rear diff---->Amsoil SVO 75W-140 {had to add 4oz. of friction modifier}.
T-case----->Amsoil Torque Drive ATF

You can run 75W-90 in the front--I run the 110 cause I use the front diff more then most. Thicker is Better!

Something to think about-->If you tow alot, which I pull our 5th wheel all summer. Next fall I will change my rearend fluid again, this time I will install a rearend cover that has a fill plug and drain plug, so I don't have to take the darn cover off every time. Plus it will be aluminum and have fins to help cooling, plus hold 1qt more to aid cooling as well. Something to think about if you tow alot.

 

[dennisj2003]

I'm a big fan of RP products.
Does anyone have experience using the RP ATF good in the xfer case and RP Max Gear lube in the diffs?

Yes they are right use Mercron SP in the tranny.

But to answer your question as you ask about the transfer case and diffs, my book says use mercron IV in the Xfer, the gear lube is a synthetic 75/140 plus 8 ounces of friction modifier in the rear, 6 quarts will change both,
as for RP I havent used it. but it should be ok alot of people use it, Just dont forget 8 ounces of friction modifier.

Sorry dave he did ask in his first and last post about the transfer case and diffs not the tranny. He said he was starting with mercron SP.

 

[dennisj2003]

Let me make this clear: DO NOT USE ANYTHING EXCEPT MERCON SP in your transmission!!!!! There are NO other options and DO NOT LET ANYBODY TELL YOU SOMETHING ELSE!! Use only Mercon SP.

Dave

He said he is using Mercron SP. am I the only one that can read?

 

[VinceJE]

Thanks for all the input.

...and yes... I know the tranny fluid must be Mercon SP. I think I mentioned this in the first post that started this thread.

I didn't mean to start another oil brand slam/debate. I just wanted to know if anyone had experience using RP products in the xfer case and diffs.

I guess I only triggered the "anti RP" folks. I'm not surprised that folks who sell Amsoil is on the hatin' side of RP. This actually gives me more confidence in RP.

There's a million people on each side of any oil brand related question. Half will hate the product and half will swear by it. I happen to be in the half that likes RP. I don't necessarilly think it's any better than other syn oils/fluids, but I have been using it for years with good results. I use it in everything I own from the F350 to my outboards to my lawn mowers. Plus, it's a local company and I like the idea of supporting my neighbors when the provide a good product or service.

 

[kingkevindavid]

I just changed all my fluids and put RP in everything except the Tranny, I had that flushed and refilled at the dealer. I personally think its a pretty good deal to just let the dealer flush and refill the tranny. The total cost with the inline filter was a little over $200 and you get ALL the fluid changed.
I used weights IAW the book and it all seems good (about 2 weeks now)
Biggest difference seems to be the engine running a lot quieter with the RP.

Beware of sticker shock changing all the fluids at the same time, expecially with RP or any syn in general!!