Differential service - how bad did I get ripped?

While '02 TB was in for an oil change last night mechanic recommended servicing all three differentials (well two plus transfer case I guess). I'm at 38k miles and probably 37k has been in 2HI. All three are synthetic fluid and they charged $400!! So how bad? I know this should be done but I would have gone to at least 60-70k.

They coulda kissed you first! You could have changed engine oil, the diffs and transfer case with top shelf lubes for well under $100. I think the 2002's even have a drain plug on the rear diff so you don't even have to remove the cover & replace the gasket or make one with RTV. Front diff and xfer case both have seperate drain and fill plugs. You should use the GM Autotrac xfer case lube which is $$, but I dont think it would run you more than $20-30.

Joel

Thanks Joel. Well it was a little less but still a rip. About $80 each for the front and middle and $120 for the rear with synthetic. I didn't see a gasket on the parts list so I suspect you're right! Well, it won't have to be done again for a long time, if ever. Like a dummy I refused the more difficult one (steering fluid flush) which I struggled through myself.

Synthetic diff oil is about 16/qt, rear cover on a 2002 has to come off, ft is drain only, whole job is about 1.5 hours tops, auto trak is about 22/qt.

what fluids exactly are recomended for the frt. and rear diffs. i have 52000 mi. and wanna replace the fluids. is the transfer also required to be changed at 50000?

what fluids exactly are recomended for the frt. and rear diffs. i have 52000 mi. and wanna replace the fluids. is the transfer also required to be changed at 50000?
Owners manual has it all.

Maxwedge, are you sure "rear cover on a 2002 has to come off"? Mine wasn't touched but I think there may be a plug/plugs on the passenger side??

sdf- some of the TB/rear diff combinations had a drain plug at the bottom of the rear diff. My 2005 with 3.43 gears, open rear diff has a boss for the drainplug at the bottom, but of course there's no plug.:banghead: On a warm diff, you can get away with trying to suck out the gear oil thru the fill plug, but you'll only get some of it out that way. You really should pull the cover. If a gasket is avail, use it. If not, just use RTV. Most are just RTV's these days.

Joel

Gggrrrr!!!!! Now I've got a sizeable puddle of front differential fluid on the garage floor! Anyone know if there's a vent if they overfilled it?? We're going away this weekend and while I don't expect to engage 4wd it still burns me. I might try to go in and have them look at it tonight.

Okay, I'll close this off. Fluid on floor was because vent hose popped off. Also the rear unit does have a drain plug. Thanks all for help!

Okay, I'll close this off. Fluid on floor was because vent hose popped off. Also the rear unit does have a drain plug. Thanks all for help!
Reason for pulling the cover is to properly clean the bottom of the housing and get all the old fluid out. Closed out!

I changed all the fluids on my 02 last July with 50K. There are drain plugs on both diffs in my TB and I used synthetic lubes for them. Dont put anything but GM AutoTrak II flud in the transfer case unless you want to buy a new one. There are no other fluids that will work for it.

I paid about $8 a qt for the gear lube. 2 litres of AutoTrak II (plus a fuel filter) was about $45 from my stealership and it was in stock.