ok, the truck just turned 52,000 miles, and thought i ought to change the tranny fluid, I took the truck to jiffy lube and they changed out ~7 quarts from draining it and put on the spin on filter that i supplied, my question is,now I see they are saying the recommended fluid is no longer dexron 3. whats up with this and does anyone think using their fluid is bad?

First, of course, this topic has been covered quite a few times before . . .

From the Allison website:Effective January 1, 2007, General Motors no longer licenses DEXRON ®-III fluids. DEXRON ®-VI fluids may be used in the 1000 and 2000 Product Families transmissions beginning with S/N 6310670488 and 6320784373; . . .
As I understand it, the 3rd digit is where the transmission was manufactured, so you would have to check the s/n cutoff using either the 631... or 632... range. I don't have the quote, but some of the seals in the older transmissions might not hold up with extended use of Dex VI. [edit: or maybe the 1 is for 1000 and 2 for 2000; feel free to search if you need that info.]

GM claims that Dex VI is backwards compatible and can be used for most Dex III applications. "Dexron III" no longer exists because GM retired all licensing of that name. If I understood the Allison site, Allison has a spec they call TES 389 for fluids formerly known as Dex III, but those oil producers would have to apply for that spec to be on their label.

Personally, I am using and plan to continue to use "Mobil 1 Synthetic ATF Mult-Vehicle Formula" (then in small letters, "Ford, GM and most domestic & imported vehicles"). On the back it says "Recommended for 2005 and earlier GM vehicles." Notice that they can't use the term "Dexron-III". It doesn't have the TES 389 spec on the label.

Allison spec TES 295 is a superior spec for all of these transmissions but is harder to find and more expensive. Examples are Transynd and Mobil Delvac ATF.

Transynd.

X2 on the transynd

IMO running DEX VI in this truck could be a mistake. There are known seal compatiblility issues when DEX VI is used in the older transmissions like yours. DEX VI can harden seals that are ok with DEX III.

IMO using a TES-389 or TES-295 licensed product will minimize the risk of seal hardening/leaking.

I went to auto zone to check out prices. They had Castrol Dex lll and Dex lv syn ATF The Dex lll was $3.99qt. and the Dex lV was $6.99 qt. On the bottle of DEXlV it said it was compatible with DEX lll I have a 2004.5 with 56K on it Need to change fluid before I tow 15K# 5th wheel.

Your best bet is a 295 fluid or a clone of it.... Your truck will thank you for it! If I can help you with anything, let me know.