Hey all.

I just purchased an 03 Duramax 3500 crew cab dually. The truck I got didn't come with an owners manual.

I want to do a fluid change on all the components and was wondering what quantities to get. I don't know the last time all the fluids were changed. I'm wrench savvy, just need to know the amounts and types if you got 'em.

What I want to change. Engine oil and filter, trans (full flush and filter), Transfer case, front and rear diffs.

Thanks.

Welcome, you should probably exercise the search function, mainly in the maintenance and fluids section. I'll tell you off top of my head what I know real quick.

Get your choice of good quality oil, I also have '03 dually, buy 11 quarts, I run Rotella T Synthetic (5-40w). Wix oil filter, 57202. Allison brand spin on transmission filter, sorry don't recall the part number. I'd have to look, but if you completely drain the Allison with the drain plug, you better buy 2 gallons to have on hand.

Can't say about the rest, I would hate to mislead you. A supporting vendor is fleet filter.com, check them out for all the filters required.

Again, the search is your friend.

good lord this forum is huge. Can someone move this thread to the "maintenance and fluids" forum? I didn't even see that.

Thanks.

It's been a while since I changed my fluids although they're due soon so here's some things to search for:

- rear diff is 4 quarts. If it's never been changed, you may be surprised that it's low. Many members have reported that their rear end was low from the factory. Typically 75W90 synthetic (GM used their "grape juice"). Think it's a 3/8" drive on the bottom to open the drain plug.
- transfer case and tranny is Dex III or equivalent. I would suggest going synthetic such as Transynd which is made by Castrol for Allison. Drain and fill for the tranny is 7.4 quarts, full drain I think is around 12 quarts (?). Don't use a flush machine - it'll potentially damage your Allison. Do a search for the "hoot method" of draining by disconnecting your transmission cooler line and running your truck to drain the transmission fluid out...easier with 2 people so one watches while the other gets ready to turn off the truck. Transfer case is 2 quarts...some will try to fill up to 3 quarts. Go with synthetic as well. Do a search for "pump rub" to see if your transfer case has fallen victim or not.
- front diff...can't remember but I think 2 quarts. Do a search for "white vent cap" if you go with synthetic. Some of the '03s had black vent caps (not compatible with synthetic fluid over time)...just buy a white vent cap and you're good to go with synthetic - 75W40 as well.
- engine oil around 10 quarts. Wix or GM oil filter is fine. Rotella, Rotella T, Mobil 1 Delvac, Shaeffer's, Amsoil...lots of choices. Typically 5W40 or 15W40. I'm running Mobil 1 Delvac 5W40. While you're under there, there are 11 zerks to lube.
- Allison spin on. Change it every 5 K...preference is the Allison spin on. Go to the Allison website and search for a dealership that's hopefully close to you. Don't forget there's a magnet on top of the spin on. If it's not there, then check the filter housing. Otherwise, it was accidently thrown out during a previous spin on filter change. Buy one (only around $4) from an Allison dealership or from one of the vendors on this site (ie: Merchant Automotive). Actually, buy an extra one as a spare.
- fuel filter...new GM filters are dual pleats (as indicated by a "B" on the part #) or go with a Wix. You'll need a WIF (water in filter) wrench or carefully use some Channel Locks to remove the sensor on the bottom. Definitely change the fuel filter frequently and keep a spare in the truck for emergencies when you get some bad diesel or if your fuel gells. Use a fuel additive (especially in winter) like Standadyne.

Sorry, my spec sheets are at the office so the quantity is from an aging memory. Do a search, it's all there. I think Eric Merchant had a Duramax maintenance schedule sticky at the top of the "maintenance and fluid" category.

You probably know a bunch of this stuff already so just do it. Cheers!

try this, it has all the capacities for any vehicle 1980 and forward.

http://www.amsoil.com/scripts/runisa.dll?amsoiloaf:index

try this, it has all the capacities for any vehicle 1980 and forward.

http://www.amsoil.com/scripts/runisa.dll?amsoiloaf:index

Wow, that one should be a sticky. Great site

I can't type like jedmax, (or remember), so:
fluid changes - http://www.dieselplace.com/forum/showthread.php?t=198162

T-case alternate lube with +1 qt - http://www.dieselplace.com/forum/showthread.php?t=148592

grease zerk locations - http://www.gm-trucks.com/forums/index.php?autocom=ibwiki&cmd=article&id=402

fuel filter change - http://www.dieselplace.com/forum/showthread.php?t=1508

trans flush - http://mdt.volvospeed.com/repairs/allison_atf_filter.html

front diff white vent - http://www.dieselplace.com/forum/showthread.php?t=22495&highlight=Front+Drive+Axle+Vent+Hose+Connector+Rep lacement

I can't type like jedmax, (or remember), so:
fluid changes - http://www.dieselplace.com/forum/showthread.php?t=198162

T-case alternate lube with +1 qt - http://www.dieselplace.com/forum/showthread.php?t=148592

grease zerk locations - http://www.gm-trucks.com/forums/index.php?autocom=ibwiki&cmd=article&id=402

fuel filter change - http://www.dieselplace.com/forum/showthread.php?t=1508

trans flush - http://mdt.volvospeed.com/repairs/allison_atf_filter.html

front diff white vent - http://www.dieselplace.com/forum/showthread.php?t=22495&highlight=Front+Drive+Axle+Vent+Hose+Connector+Rep lacement


I didn't have the patience to search, read, copy and paste like Modified. :D

Down here, we'd start this thread with:
Hey Yall! :D
Besides that, everyone is giving good info. :)