All things fluid.

[lamerem]

105,000 miles on this tank, and it's time for a blood transfusion. I'm prepping to change the fluid in the transfer case, front differential and rear differential. So far I ordered the rear diff gasket (I know that I could reuse the old, but since it was available I went ahead for piece of mind), picked up 5 quarts of Mobil 1 75w90, and 2 quarts of ACDELCO Dexron VI full synthetic (10-9243). I also bought one of those fancy little hand pumps from the big box store to make my life easier.

I went through the manual and it said to use the fluid weights I got, except for the front end it said use 80w90. I contacted a friend of mine that is a service writer at the dealer and he said the tech told him 75w90, not 80w90. Any idea why they would contradict the manual? I live in Iowa with the cold harsh winters, that is the only thing I can think of is the thicker fluid might not work as well.

Anyway, the transmission is next and I might wait until I have everything and just do it all at once. I am planning to do the fluid swap through the lines at the radiator. I am not a fan of the flushes, I've had a bad experience and won't risk it again. I am planning to use the ACDELCO filter, and new gasket as well as the same ACDELCO Dexron VI as I am using in the transfer case.

Advice from others that have taken on these tasks? All I know is the dealer is looking to get rich, quoted $540 not including the transmission. They were also very much against dropping the pan, they said it was pointless as the filters were made to last a lifetime. Well, my definition of a lifetime, and theirs I believe to be different. If the parts are available on the open market, then someone, somewhere thinks the need to be serviced. Besides, its only like 13 bolts and the pan is off, BLAH.

Lastly, someone posted on here somewhere (which I can't find now) that you should change the pressure sensor/switch/pump while the pan is off? Anyone know anything about this?

 

[swathdiver]

When doing ours earlier this year we used the factory fluids, including the front differential's 80W-90 non-synthetic. Drop the spare when doing the rear to make life easier. I've re-used my rear differential gasket twice without sealant and its just fine.

As for the transmission, same for my dealer, they took the stick out of the new transmissions and call them sealed now. No more checking or changing the fluids. The TransFlow machine when properly used works just fine. I had to get over thirty years of doing it the other way since I could no longer do that myself without great effort.

1.51 Quarts of 80W90 for the front differential
1.6 Quarts of Dex VI for the transfer case
12.4 Quarts of Dex VI for a fluid exchange or 6 Quarts for a drain and fill (old school from the pan)
2.15 Quarts of 75W90 synthetic GM (New Grape Scent!) for the rear differential

 

[Doubeleive]

I just had my front diff, rear diff, transfer case, and transmission done (filters and gasket included) with the addition of installing a deeper trans pan that holds 2 extra quarts and I was out the door for $540, the B&M trans pan ran me $240 but that was a separate purchase of my own. this is from a very reputable shop and they never mentioned anything about doing any sensor or pump or I would have had that done as well. so ya I would say the dealer is trying to get extra money out of that no doubt, the transmission was last done at 45k according to service records when I purchased it, now it is at 90k, I do all the fluids front to back annually so I was a little skeptical that the transmission would be ok after not being done for 45k, having it done annually seems to make things go a little more farther than they would if not serviced in my opinion, ever since I started doing it annually I have had less failures.

 

[lamerem]

What is the benefit of the 2 extra quarts?