Some thoughts on replacing drive line lubricants

[Chuck Tribolet]

I'm changing the drive line lubricants on my '01 manual transmission PF this morning, and I'll comment here as I go along.
They've been in there for 215K miles. I used Valvolene DuraBlend Synthetic Blend 80W90 in the diffs, Valvolene
High Performance 75W90 in the transmission, and will use Valvolene DexMerc in the transfer case on another day.

The front diff oil was much much cleaner than the rear diff. The front oil looked new, the rear diff oil was black.

I was really glad I had http://ultimatetoolco.com/13mm/. The fill plug for the rear diff wouldn't come loose with a
breaker bar. I put this gizmo on Ingersol-Rand's baddest 1/2" impact wrench, and it came lose, but not immediately. This
is a good reason to remove fill plugs before drain plugs.

Do the front diff before the rear diff. They take the same oil. You get almost all the oil out of the bottle into the rear
diff, but not so much into the front diff. You can use three partial bottles on the front, and finish them on the rear.

The oil for the front diff looked great. I don't use 4x4 much (just launching and retrieving my boat). I'm not sure I'd
bother changing the front diff oil next time.

Getting the fill plug back into the front diff is tough, at least for my big hands. I'd suggest having handy 6" extension
for 1/2" sockets to get it started.

When I pulled the fill plug for the transmission, a fair amount of oil ran out and made a mess. Have the drain pan
handy.

You can fill the front and rear diff by squeezing the bottles, but no way for the transmission. I picked up this:
http://www.summitracing.com/parts/SPE-5971/ on a $20 sale at Summit Racing (THANK YOU to whoever posted
that sale over at CorvetteForum.com). I discarded all of the hardware, kept the pump and hose, and it filled the transmission in no time
flat. The pump does suck a little air, so I gave it a breather at 4.5 quarts and 5 quarts to let the air get to the surface.

I'm going to do the transfer case another day. It also needs the pump, and I need to clean out the pump hoses.

Chuck

[Towncivilian]

Whoa whoa whoa, you're using GL-5 rated gear oil in your manual trans? It's specified for GL-4 75W-90 fluid only. How long have you been running non-GL-4 fluid?

Naturally the front differential will have cleaner oil since it's only used part time, after all. I'd be most concerned about potential moisture accumulation which may occur if the fluid does not ever get hot enough to boil off the excess moisture.

Where do you purchase your gear oils? If there is Advance Auto Parts in your area, you can get 5qts of Mobil 1 75W-90 gear oil for your differentials for only $34.95 before tax if you order online using discount code RETMENOT123 and pick-up in store.

I too am happy that I got a 13mm drain plug socket. Mine's from Harbor Freight, but was available locally and relatively cheap (~$14 for the drain plug socket set with 20% off one item coupon).

[Chuck Tribolet]

It meets both GL-4 and GL-5.

No Advance Auto around here. I had to look pretty hard to find anything that wasn't house brand.

Chuck

[Towncivilian]

You're correct - I had to look at the product data sheet and it says GL-4 and GL-5 rated. I would typically be hesitant of running a dual-rated fluid in a manual transmission since generally the dual rating is for use in differentials, but the PDS specifically states it's recommended for use in manual transmissions.

Ah, that's a bummer. Advance Auto has great discount codes, they're easily my favorite parts store just due to that. The Valvoline stuff should serve you well though.

[Chuck Tribolet]

There's not much that's not dual-rated.

BTW, folks, GL-5 does not mean better than GL-4. GL-5 means for big bad nonsyncromesh trannies (e.g., 18-wheeler).

[Towncivilian]

Yeah, pretty much the only GL-4 only rated stuff is boutique fluids (Amsoil, Redline, etc). You're correct about GL-4 and GL-5 being separate specifications.

You've got the part-time/manual transfer case, correct?

[Chuck Tribolet]

Yes, part-time manual transfer case.

Chuck

[Towncivilian]

Alright, just making sure since the auto transfer cases have a filter that can be removed and cleaned with brake cleaner; it's just a strainer assembly like the one found in an automatic transmission. A replacement OEM filter is around $115 and no aftermarket filters are available.