Transmission maint

mick16g · January 17, 2004

My 2002 HD has 5200 miles on it. I was going to change the control filter on the transmission and after looking at the allison web site, the recommend changing the fluid at 25K or 12 months. Since my truck is on it's second year, I am thinking of now changing out the fluid. Do anybody do this.. Also, how do you put fluid back in. I see a fill plug on the transmission diagram, but it doesn't look easy to get to.

thx...

JayMan · January 18, 2004

According to the Allison Quick Service Manual, the Initial Change should be at 5,000 miles, then every 24 months or 50,000 miles. This is the "General Vocation" duty as your truck will see.

Every 12 months or 25,000 miles is for "Severe" or "Transit" duty. That would be like a city transit bus, a garbage truck, dump truck, etc. Of course, you won't HURT anything by changing the ATF more frequently!

Allison transmissions are made for many different applications. The "available fill plug" (Left and Right side of trans) is where the transmission diptstick tube plugs into transmission with a grommet or o-ring.

So you can fill the Allison using the transmission dipstick tube. You will need one of those skinny Automatic Transmission funnels from the parts store.

Remember: overfilling is just as bad, if not worse, than underfilling. Some folks like to drain their trans pan into a container, then drain the control filter into the same container, then spend some time seeing how many quart bottles it will fill.

Takes forever but at least you would know EXACTLY how much ATF to put back in.

Good luck!

inscom · January 18, 2004

...wonder wether anyone ever used on of those fast oil-change outfits. They flush the old stuff out and the new fluid right in agaien without loosen on bolt.

JayMan · January 18, 2004

...wonder wether anyone ever used on of those fast oil-change outfits. They flush the old stuff out and the new fluid right in agaien without loosen on bolt.

Geez I'd be careful with that, especially if the trans had a lot of miles on it. You'd knock all that sediment and sludge loose in the pan and filter, then REALLY have problems.

Like most HD Allison's, the AL1000 has an external spin-on filter. There is also a filter sock in the pan, to protect the pump from floaters and chunks.

So if you changed the spin-on, especially when done at the recommended 5,000 mile mark, and had a "flush" then it might be ok.

I'm just wondering why torque converters don't have drain plugs anymore? My 1984 Ford F-150 with C6 has a tiny TC drain plug, and if you're patient, you get 99% of the ATF out. No monkey business with "flushing" it out.

Roofer · January 18, 2004

Mick,

Change the spin on filter and add about a half quart through the dipstick. I used Napa synthetic. I am not going to worry about it after that because I rarely tow anything big.

As for the fast lube places, I never trust them. I knew too many morons that worked at those places and heard too many stories.

JayMan · January 19, 2004

I have to go with Roofer regarding his comments on those fast-lube places. Most are staffed by loser high school punks who could care less about your ride, and if anything goes wrong, their fine print gets 'em off the hook.

I just got back from Tim Horton's and my morning coffee/yummy roll. Geez, -36 F and a nasty windchill. I usually sit down with the local GM Service Manager to shoot the breeze. I casually mentioned how easy it was to service the Allison and he brought up some scary points:

1. Allison 1000 rebuilt is $3,888

2. He only knew of 2 local Allison owners who bothered to service

3. Has already had a few complaints about cold shifting.

Ok, regarding point #1. Say it takes 10 quarts to drain the sump and change the spin-on. With Mobil 1 ATF (Allison certified to their tough C4 spec) priced at $5.25 / qt, that would be $52.50 plus the spin-on plus tax. Say the spin-on costs $10, so say $75 in parts to service the Allison at 5,000 initial miles then you become picky and do it every year.

It would take slightly over 50 years to equal the cost of a rebuilt Allison. I'm not considering Future Value, dollar depreciation, etc. Still, there is an old saying "penny wise dollar foolish."

Point #2. I'm astonded that somebody will happily cut a check for +$6,000 worth of motor and transmission options and NOT look after it. What is this, "more money than brains?" Nope, that's an "oxymoron." I've never seen a single case of "more money than brains."

I've had some experience with an older 400 Series 4 speed auto Allison, and those things are built like a brick s*** house. They're also remarkably easy for the DIY to service. So unless you have the mechanical apptitude of a turnip, why pay somebody to service it??

Even though Allison claims you don't have to drop the pan for routine servicing, some folks also like to drop the pan just to check for residue and for chunks stuck to the magnets. They figure it's so easy to service, what's an extra 15 minutes to check the pan? Though I have to stress you really don't have to, as the spin-on and the magnet above the spin-on should catch everything.

Point #3. Like all HD Allison transmissions, the 1000 should be "preheated" before operating in cold weather. Allison used to recommend a 20 minute warm-up colder than -10 F if using a regular C4/Dex III, colder than -20 F if using a synthetic C4/Dex III. This has changed only slightly with the AL1000 (Cutoff temps now -13 F and -22F respectively).

You WILL cause damage to the Allison if you treat it like a gasser by hopping in at -25 F, firing up, slamming it into Drive, and taking off. The local dealer goes through great pains to carefully explain that to customers when they have problems in cold temps.

The new Allison is actually designed to "inhibit" certain shifts or modes until the fluid is at operating temp. Of course, the customer then complains about what a p.o.s. the Allison is.

So service it yourself, it's quick and easy. Especially when you consider what an Allison or ANY transmission costs if you fubar it, don't penny-pinch by refusing to service. Don't forget to inspect/clean the magnet on top of the spin-on.