I know I'll get hammered for this but what fluid is best for Allison trans. I have a 03 2500hd with 245,000 on it. . I'm putting a ppe pan on it and just wondering if there is a fluid recommended for it. Any help is much appreciated.
I think any Dexeron III is good or synthetic transynd, if you have an allison that is on an 06 model you have to use Dexeron VI but is compatible with Dex III. Hope this helps.
Should be good to go with that. If you haven't purchased the deep pan you can get the larger one there too or just grab what looks like 3 gallons of Transynd, internal and spin-on filters.
From what I understand if you put it in the older 5 speed Allison's it will cause leaks because dex VI will ruin the rubber seals. After 05 or so they updated the rubber seals and then they were compatible with dex VI. I am a firm believer in this because after I bought my 03 I flushed the fluid and put dex VI in it. Over time it started leaking from several places.
Edit: I bought the truck with 180k on it and there were no Trans leaks. Didn't want you to think I bought the truck new in 03 lol