all drivetrain fluid change

[tnord]

my workhorse is going to turn 100k in about 30 miles, which means it's time to get out all the old fluids. i've been searching and reading for the last hour but i can't keep all these different configurations and systems straight. i'm very much a DIY'er and would love to spend an afternoon on the garage floor taking care of this myself. but all of my experience is on simple 4cyl manual transmission stuff. all this crap with torque converters, transfer cases, 300gallon fluid capacities, filters,flush vs drain, autotrac vs non-autotrac, etc etc makes my head hurt.

 

 

my truck is configured as such:

 

2001 5.3 4x4 Z71 w/tow package.

 

i tow about a 5000lb load somewhere around 7-10 times per year and am going to switch to synthetics throughout. my 3 options for what i'd be willing to put in there are Amsoil, Redline, or Mobil 1. i'm guessing i can toss in the 90-140 amsoil into the rear diff just like i do in the race car, but everything else i don't know what i need. it looks like my trans oil pan gasket is leaking, so i'd obviously do that at the same time.

 

after this i need to solve my exhaust leak issue, then replace the o2 sensors, then figure out my startup problem.....but that's another topic entirely.

 

i know, but like i said, i searched and i can't keep all this stuff straight.

[Elwood 2000]

I have just done all this to my 2000 Silverado. I bought the rear oil from GM. It has the proper additive for the rear limited slip. I also bought the Autotrac fluid from GM, as well as my front diff. oil. Probly didn't need to with the front, as it is not synthetic, but I was there.

 

Buy a new drain plug for your transmission. It is a "GM only" part, about $5. You will need it. Since your pan is leaking, you should change your tranny filter while you are in there. There are synthetic tranny fluids available, but I just went with a standard fluid.

 

From what I gathered from folks on this site, the GM Autotrac II fluid and the rear end oil with the proper additive is a must. Everything else is at your descression.

[Indy]

This was dicussed about 2 days ago. 75w90 synthetic in front and rear diff. Transfer case 2 quarts GM Autotrak II blue in color.

[Black02Silverado]

There currently isn't a replacement fluid available for the AutoTrac II fluid from GM. So that is a must to get from the dealer. Two quarts will work just fine for the transfer case.

 

75w-90 in front and rear diff's will work just fine. I wouldn't put the 75w-140 in the rear. Thicker isn't alway better even if your towing/hauling alot.

 

The rest is pretty easy. If you are interested in Amsoil, let me know. I can quote you a price delivered to your door.

[tnord]

that's interesting about the autotrac. what is it about the autotrac fluid that makes it non-compatible with stuff from other mfg's? does this stuff have to go in the transmission as well as the transfer case? if it's the same stuff does that mean the transfer case and the transmission have to be done at the same time? sorry, i'm pretty clueless as to how this automatic transmission stuff works.

 

i'm not saying you're wrong, but what makes you say that the 75-140 wouldn't be a good idea for the front/rear diffs? it has friction modifier in it already like elwood was talking about correct? it's the same stuff i use in my LSD for the race car, so i figured it would be good in the truck, but maybe i'm wrong?

 

i have a local contact for amsoil already. i get the 75-140 for $11/qt from him. if you can get it to my door cheaper i'm all ears!

[GTUSN2006]

I have a HD, so it might be different, but my manual called for 75-90 in the back and 80-90 for the front. If you use synthetic in the rear then you dont need anti-slip additive. It might not make much difference, but i put what was called for in. The back of your owners manual should have specific information for your truck.

 

Also, while you are under there you probably want to hit your grease zerks. I had to pump quite a few times on a couple of them and my truck only has 36k. There is a good write up on the how to section of the website that tells you where all 11 are.

[tnord]

that's a problem i should've mentioned, i bought the truck used and don't have a service manual.

 

grease zerk? is that like a slang term for those guys in leather jackets and white t-shirts in the 60's?

 

<----jealous of your HD. once i get the money (which will probably be another 100k miles) a 50' trailer and a duramax/allison is calling my name.

[GTUSN2006]

Below is the link for the locations. They are just small fittings that allow grease to be inserted with pressure. I actually noticed my ride to stiffen up (not as bouncy) and the front suspension seems quieter. But that could all be the placebo affect. You just need a grease gun, a flex hose for the grease gun would be helpful (I use 18 inch) and a tube of grase. I used Mag 1 lithium.

 

Grease Zerk locations

 

Hopefully someone with a 1500 can verify this, but here is what my manual says for the fluid changes.

 

Rear Diff: 75W-90 Full Synthetic (then you dont need anti-slip additive)

Fron Diff: 80W-90 (I used a synthetic blend)

Trans: Dexron III ATF

Trnsfer Case: Auto-Trak II Fluid

 

You have to buy the Auto-Trak Fluid from GM, but I would get your own for everything else. It would save you alot of money. Overheard them say twenty something for a quart of 75W-90 the other day.

 

 

Actually, if you just look here, there is a write-up for pretty much everything you are doing/

How To Section

[tnord]

thanks for the help. i didn't even know cars had grease fittings anymore. i'll pick up a grease gun and whatnot when i go to the store tomorrow. is this a body-on-frame unique thing?

[GTUSN2006]

Its all the front suspension components that you end up grasing.

[Black02Silverado]

that's interesting about the autotrac.  what is it about the autotrac fluid that makes it non-compatible with stuff from other mfg's?  does this stuff have to go in the transmission as well as the transfer case?  if it's the same stuff does that mean the transfer case and the transmission have to be done at the same time? sorry, i'm pretty clueless as to how this automatic transmission stuff works.

 

i'm not saying you're wrong, but what makes you say that the 75-140 wouldn't be a good idea for the front/rear diffs?  it has friction modifier in it already like elwood was talking about correct?  it's the same stuff i use in my LSD for the race car, so i figured it would be good in the truck, but maybe i'm wrong?

 

i have a local contact for amsoil already.  i get the 75-140 for $11/qt from him.  if you can get it to my door cheaper i'm all ears!

 

 

 

 

 

 

The auto trakII is just for the transfer case. The transmission takes regular Dexron III. They do not share the same fluid together. Each is seperate from the other. GM has not released what the Auto Trak II is made up of so other manufactures can't copy it. If it was a known formula there would be more available. It took a while for GM's synchromesh fluid to get out into the market place when it first came out.

 

If you can get the Severe Gear 75w-140, out the door for $11 a quart. That is an awesome price. My cost is $10.15 a quart and that doesn't include shipping and tax. Retail price a quart is $13.10. He must pick up his supplies from a distribution center to save on shipping.

 

GM doesn't call for such a heavy weight in the rear differential for a 1500. That is why I wouldn't recommend putting it in there. Now your race car, if it is just a track vehicle only and not used on the street that is a different application due to the stress of racing.

If you want to run a heavier oil in the rear diff that is up to you. It just isn't recommended by GM and I try to go by that. The LSD in your race car is also a different set up than what is in your truck. You can go to the Eaton Web site and read the difference between the G80 that your truck has and other LSD's.

 

Again, if you can get Amsoil at those prices that is awesome. I wouldn't pass that up.

[tnord]

thanks a bunch. i'll probably end up with the 75-90. when i think about it, there really isn't any reason to go up to the 140. if i was doing a bunch of offroading, or i was putting out a ton more power, then there might be a reason to put it in. but just street driving and towing every once in a while doesn't justify putting in the thicker stuff and sacrificing some power.

 

hopefully i can get around to this next weekend. i've got an acura with a blown headgasket that needs attention, as well as a race car with a junk gearbox and a blown ring/pinion. sheesh i've got a lot of work to do.

[Elwood 2000]

Rear Diff: 75W-90 Full Synthetic (then you dont need anti-slip additive)

Fron Diff: 80W-90 (I used a synthetic blend)

Trans: Dexron III ATF

Trnsfer Case: Auto-Trak II Fluid

 

That is correct! The rear diff. fluid has grape scent!! Yes, I read the bottle from GM and it said "grape scent". That must be why it cost so much!! Actually, the front and rear oils were not that bad, but the Autotrac II fluid was $17 per quart!

[tnord]

if instead of taking it to a service shop to hook up the flushing machine (not the toilet) i changed the fluid, drove it for 5 miles, then came back and changed it again, would that function as well as having it flushed?

[Black02Silverado]

if instead of taking it to a service shop to hook up the flushing machine (not the toilet) i changed the fluid, drove it for 5 miles, then came back and changed it again, would that function as well as having it flushed?

 

 

 

 

 

If I ever get another new vehicle. What I will do is just change the filter and fluid in the tranny, then at the next four oil changes do just a fluid change on the transmission. Way cheaper and in the end the results the same, plus your adding fresh fluid over time and not shocking the system all at once with fresh fluid if you have a few miles on your vehicle.