I have an 01 2500HD with a 6.0 and 4L80E that is at 98,855 miles and Im startin to plan ahead for 100,000 mile service. I was plannin on a trans filter change and change rear diff fluid. Im wondering what fluids to replace these with. I was planning on staying with a synthetic in both. I was also wondering if I should stay with synthetic motor oil? I have been using Mobile 1 High Mileage synthetic. Im also wondering if I should go ahead and change the brake fluid? I havent had any brake fade at all but I know I also havent had to add but maybe half a cup over the past 70,000 plus miles. Does anyone out there have any suggestions on what else I should look at? I have a mystery coolant leak also that I think is coming from the water pump gasket itself. Was this a common problem? The truck isnt running hot, every 2 weeks or so I put some in and its fine. No other problems. I was gonna put a new pump on, fan clutch and thermostat.

 

Yes. Yes.


I would change my brake fluid annually if I weren't so lazy, because it firms the pedal so much. It would also help prevent internal corrosion, and keep the bleeders free.

 

Thanks for the info. Any input on the fluids situation?

 

when you get to 200K . . . then start using the high mileage full synthetic

I would run full synthetics in the engine, trans, and the diffs. I ususally use Mobile 1, but if you're doing everything, try and find a Royal Purple dealer.

Change the:
engine oil - and no fram filters . . . use a WIX or Delco
Trans - just Change the oil/filter twice . . . first with some cheep oil, then the second with the full synthetic. . . . DO NOT DO A FLUSH

Diff's . . . 80-90w or 90-120w full synthetic . Use RTV for a gasket/sealant . . . don't bother with the paper gaskets

New belt

check the brakes - if you have 4 wheel disk . . . look a the parking brake on the rear drum. It likes to drag, burn up and crack
Brake fluid - If it's not clear to motor oil looking . . . change it out

Water leak - replace the gaskets, and put some new coolant in. Check
the radiator cap.

Steering/suspension - Idler arm is usually the first to go . . . swap it out to a Moog. I can't stand my stock shocks . . . I'm planning on getting some Bilsteins. Either the yellows or the 5100s.

Top end engine cleaner - Use Seafoam. Do a search on here. There's plenty of topics on it. . . . but suck it up from the brake booster line from the back of the intake, with a really small hose. Get the engine hot first, then suck the cleaner up . . . (smoke show) . .. let it sit for 20 min, and then go out and drive it. It'll eventually clear up, but it will smoke, and stink for a while.


Get a performance tune . . . and you'll get better gas mileage out of it

 

Okay Common misconception here is when your engines getting higher in mileage is to switch from conventional oil over to full synthetic. which the Pennzoil commercials have every one convinced that the sludge in the bottom of there motor is a bad thing. don't get me wrong its not the greatest thing for them but stop and think about this. you're engine is getting higher in mileage the seals are starting to get worn out and its the sludge that's built up around the seals thats preventing it from leaking. Okay now add your full synthetic that cleans the sludge which is not a lie,the seal that was cooked and had the sludge around it sealing now that that sludge is all eaten away you have your self an oil leak.

now you can call me a liar and say that every one at Napa or where ever you get your oil changed at says its better but in reality consider how many of them are salesmen and women who are trained to try and up sell products

Moral of the story keep using the same type of oil you have been using prior

 

First off I work for a local Advance Auto here in town. I tell people once they hit 90K or so that they can switch to a conventional. I run Mobil 1 full synthetic now and have since I got the truck with 29,000 on it. It starting to use a little oil now and I was going to switch to a high mileage conventional. I always use ACDelco filters since we stock them. I love the seafoam. I sell probably 4 cases of it a week. As for getting it into the intake, I have the hydroboost system so I dont think I have a line from the back of the intake. Any other easy way to get it in? Ive heard of guys taking the intake off and using a spray bottle and spraying it into the throttle body.

Im guessing changing the trans fluid twice is to get as much crap out then run the synthetic? I had no intentions of doing a trans flush. Ive heard too many horror stories of trans needing rebuilt after a flush.

With the rear gear fluid... should I use a tube of that lube for lockers since I have the G80?

Thanks for the input guys. Im just trying to get a list going of things to do over the winter when I can put the truck inside and get the S10 out.

 

what i do for 100k tune ups...

replace spark plugs with either factory delco platinum or tr55...delco platinum is more expensive but will last another 100k...ngk tr55 probably every 20k, but with the cost difference, tr55 is best bang for buck and a great plug. ngk makes the delco plugs. dont forget to put a dab of antisieze on the plug threads.

change plug wires with factory wires.

run seafoam through the top and bottom end. clean throttle body and MAF with electrical contact cleaner.

change trans filter and replace fluid with the original crap thats in it. ive never used synthetic in a transmission, and have seen some stock units last 200k without ever being touched.

change rear fluid with a name brand fluid whether its synthetic or not. if you have a factory g80 dont use synthetic and put in the posi additive.

bleed brakes.

replace fuel filter if its old.

as for your water leak, you have to find where, and the gaskets around these motors are very cheap. drive for another 100k.

also might look into running over to a lube shop and have them grease all of your zert (zurk, however you say it) fittings.

 

From Wikipedia: "The patent for the zerk fitting was granted to Oscar Zerk in January 1929"

 

Thanks for the info again fellas.

I grease my zerks every other oil change so that is covered. Im getting ready to get my S10 on the road so I can do this work in the winter time. I clicked 100,000 miles this past weekend.