Well i deserve this one i guess. I picked up a 2002 2500HD 4x4 this weekend and took the old owners word that all the fluids had been changed. Well he seamed like a nice guy and after the long drive 10 hours i was manly looking for leaks and just wanted to get home but i wish i had checked the fluids. He told me he had just changed all the fluids and filters in the truck before just a day or two before i picked it up. I finally had some time to check them today and well the angry title probably speaks for its self :mad:.

I drove the truck back home around 700 miles of highway driving and parked it for the day. I figured i would check the fluids and filters before i make a drive back home next week and was shocked at what i found. The oil is black as coal and the transmission fluid doesn't look much better. I found out it also had a K&N filter that was full of dirt and mud :mad:.

I picked up 12q of moble one 5W-40 syntectic diesel oil today bud i had no clue what transmission fluid to get. I know the Alison is one hell of a transmission but i want to make sure i am putting the right fluid and the right amount into her.

So my main question is what fluid and how much should i pick up for the old girl. I don't mind spending a little now on higher grades if it helps extend my transmission life.

I also started changing the diff fluid but i think i need one more quart. I picked up 3q and figured it would be plenty but when i started filling the empty bottles up i filled all three and still probably have over a half quart left in the pan.

Also changed the K&N filter with a Fram tough guard.

Also what transmission temperatures are you guys running unloaded. Mine is staying right around 200 under highway driving in about 80 degree temperature.

Any one. I understand that 160-200 is operating temperature but should i be on the high end of that with no load under almost perfect conditions? Also is it 8 or 13 quarts for the transmission getting a lot of mixed responses when searching.

Those trans temps are high compared to mine. Before the deep pan, cooler & TransSynd mine usually ran at 150 unloaded. I am not a trans expert, but if your fluid is black like oil, I am guessing your clutches are not in good shape, and you need to plan on a rebuild very soon before the truck picks the time for you.

Ronald Reagen said it best "trust but verify".

Good luck

I picked mine up in Houston and drove it back to St. Louis (~800 miles).

Changed the oil before I left Houston, then all the fluids when I got home (cept the rear diff).

On the drove home, with the old (probably original) trans fluid, my trans ran between 150-175F on the gauge before the f'n stepper motor went out and the gauge went haywire.

200F sounds high. As for the trans capacity. My 2005, with stock pan, took about 14 quarts when using the "Hoot" method for changing the fluid and flushing the cooler.

Thanks for the info. I just put 4 quarts in the rear diff (royal purple 75-90) and am about to start changing the transmission fluid right now. I picked up 13 quarts of moble D/F at the store. I am thinking about running it in the transmission for about a 1000 miles and then changing out to synthetic to try and get all the crap out of it.

http://www.dieselplace.com/forum/showthread.php?t=239630

There's the best method for changing it yourself. I just used std Dex III fluid. Mine will hit 5 yrs way before the 50k miles required to change it again.

CBR600--Here's a link to the Sticky on ATF:

http://www.dieselplace.com/forum/showthread.php?t=302701

Finished changing the fluid took about 8 quarts total and went for a little test drive. Not only is the truck shifting a lot smother but even after a few good hills my trans temp gauge is leveling out at about 160 now. I check the new fluid after about 15 miles of driving and it looks much better then the old stuff which i will be taking pictures of latter.

I was shocked at how dark the old fluid is and i agree its not a good sign for the future of the transmission. It looked more like engine oil that was nearing the end of its life instead of transmission fluid. The bad part of all this was i picked the truck up off of a member on this forum that i trusted. Defiantly a lesson learned.

I would also suggest changing the spin on trans filter as well and checking the magnet for clutch material

I would also suggest changing the spin on trans filter as well and checking the magnet for clutch material

Careful not to throw out the magnet with the old ATF filter.

Thanks for the heads up. I changed the filter with the fluid but i didn't see a magnet. I have the old filter sitting in the garage so i will have to check it out.

It's hard to miss... Great big donut looking magnet.

If the fluid is that bad, you might want to drain it and change it again, along with the interior pan filter.

When I picked up my truck, I went ahead and changed both filters, just for safety's sake.

Was the old fluid just dark in color, or was it burnt smelling too? Mine looked like a really dark blood red, almost brown.

I drain and fill with Transynd. The last time I was concerned about the color of my fluid. I took my wet dipstick into my local Allison shop. The service manager said no problem, the dye tends to fade. He said that they had the same concerns with fluid changes in their shop and had sent samples out and found no problems. You can pick up a magnet at Allison dealer and usually Transynd and spin on filters are reasonable.

No magnet on mine some one must have lost it in the past. I dont know any good allison shops around here but i should probably pick one up from GM just to be on the safe side.

The color was like very dark oil. You cant see through the clear bottle that i kept some of it in. It did have a little burnt smell to it but i think it could be from the age of the fluid. With the new stuff in there it looks like transmission fluid again but yeah i am thinking about changing the inner filter and going to synthetic fluid after i come back from VA.

No magnet on mine some one must have lost it in the past. I dont know any good allison shops around here but i should probably pick one up from GM just to be on the safe side.

http://www.merchant-automotive.com/allisonspinonfiltermagnet.aspx

Before I started abusing my stock allison it ran 160* in 80* weather...after some sled pulling with a 400rwhp & 450rwhp. it started running at about 200-210* and Now after sled pull with a 500rwhp tune it wont move. lol

She is staying right around 150-160 right now so i am holding my breath. I also finished changing the oil today. I dumped the old crap out and filled it back up with some cheap 15-40. I drove the truck for a few minuets to get all the old stuff out of the cooler and then dumped it again. Even the second time the oil was pretty black. I replaced the filter this time and added 5W-40 moble one syn for diesels.

The only thing left now is the transfer case and i have no clue what it should take. I am assuming transmission fluid and probably about 3 quarts???

If I can help with any maintenance items you need, just let me know. I carry everything needed for your truck such as transynd, internal and external trans filters, and the magnets. This goes along with all other fluids and filters. Sounds like you are doing the right thing spending a few dollars to get all the fluids changed. Your truck will thank you.

I hope so but i am not holding my breath on the transmission. I took a second look at the transmission fluid last night and you cant even see light on the other side of the bottle it is so dark.

One ticks me off is that this was another members truck and i was told that all the fluids where going to be changed before i picked it up, On top of that i was told that it had never been off road, drag raced, or pulled with. I found mud inside the intake and the air filter was freaking covered in crap.

Just change the fluid again, there is a lot of fluid in the converter that didn't come out the first time, there is a flush procedure on here if you want to do that.....the Hoot method I think.

Well i had to run to the hardware store today and pick up a few things and its still getting 190 during normal driving condition with a light foot unloaded.

if the fluid in the tranny is the original stuff from the factory the color of it is real dark almost like grape juice,takes a few changes to get it all out ,I know this was the case on my 02 duramax with allison ,your tranny is probably just fine with lots of miles left in it.

its hard to hurt a Allison besides putting to much power through it. I wouldn't worry as long as it stays below 200 or 210 on the really hot days it is fine.

How hot do you think the 4L80E got you probably wouldn't want to know I am sure it was way over 200

As far as the oil it turns black almost instantly

Flushed the engine oil system very good and its looking pretty healthy after about 75 miles. As far as the transmission goes this stuff was as black as used oil. Keep in mind i was told the engine oil and transmission fluid where changed right before i picked it up. If that's true then this truck has had 2 transmission changes and 3 oil changes in about 700 miles.

Something i have also noticed is the truck shifts kind of strange some times. Right when the truck shifts it will get noticeably louder and the RPM's seam to jump a little bit under moderate acceleration. When it does this the truck shifts noticeably harder, It almost fills like its trying to go down a gear to up shift

I would probably do a "hoot flush" on the tranny- and soon. Run it for 1000 miles or so, then switch out to Transynd or Amsoil Torque Drive (http://www.amsoil.com/catalog.aspx?Code=ATD1G&zo=1747262) (a clone) if you are planning on doing that. Yes, I would def. do the TC too- it takes 2 qts of Dex III as well (or TD or Transynd). Another thing is make sure that the tranny level isn't over full when HOT- the alli will run hot if too full. Also, FYI Royal Purple has failed shear testing- just a heads up. If you need any help with Amsoil products, information, or "you pay what I pay" pricing- PM me!! Thanks

Thanks for the info. The trans fluid is right on the full mark when hot. The only thing i am running RP in is the rear diff and moble 1 in every thing else now. I might have to wait to next payday since i have spent over 400 bucks between fluids and shocks already this month :(

I know when you fill it close to the high mark for full it will run a little warmer. run it in the middle section and you'll probably drop 10*

My choice of poor man's tranny flush fluid is valvoline DexVI 1 gal jug at Wallys for $14.xx
that reminds me I need to put in a pint for the filter change I did.

I bought my ally trans filter from a big truck service place, $7 or $8 a pop, but they had a bit of oily dirt of them....

stockrex,
Are you saying that when just the spin on filter is changed, that 1 pint needs to be added? Is it possible to fill the new spin on before it is installed?

Yes, you can add fluid to it before installing it. It doesn't hold much fluid. Don't forget to keep the magnet from the old filter, as this is frequenlty forgotten.

dino,
Thanks for the info. So if it doesn't hold much, do you actually lose a pint when changing it?

Sd Chris, yes 1 pint is what I have read you have to add to replace the fluid lost.
but now that I think about it, it does seem a LOT,
I lost couple of tea spoon of fluild when I loosened the filter and then add to that the filter capacity,

what is the filter capacity?