Allison fluid change

[DmaxProf]

I have about 31000 miles and am planning to change the fluid in the transmission before I tow again this summer. The dealer is telling me I need to change the inner filter, the gasket, and the external filter as part of the fluid change. Based on reading posts on this forum it seems I need only to change the external filter as part of the fluid change. As I understand it, the internal filer change is recommended only at a overhaul.

Can I just drain the fluid from the drain plug and then add the new fluid at the dipstick under the hood?

[Jim Brzozowski]

Yes. Don't forget to swap the magnet on the external filter to the new one.
Allison's recommendations I beleve is still only change the internal filter upon overhaul. Of course you would change if you are going to go to a deeper pan.

[Idle_Chatter]

I've made two fluid changes on my Allison. I dropped the pan for both. The drain plug is up in a "boss" that doesn't permit the pan to fully drain. The pan gasket is a large steel reinforced rubber unit and no problem to reuse it many times. Dropping the pan (after draining) allows you to get the maximum amount of old fluid out, it also allows you to wipe the metallic dust off the internal magnet glued into the pan. No access or clearance problems and really a cinch to do. The internal "filter" is a screened pickup - no "filter" to it at all. No reason to touch it unless you are changing pan depths - then you need the proper pickup to match the pan.

[Inspector]

It is not necessary to change the inner filter or drop the pan. The internal filter is to be changed out except at rebuild as recomended by alison. If you are anal go for it. There is a plug in the pan so as to make it a clean drop. The spin on filter has the ring magnet and must be removed and reinstalled on the new spin on. The gasket on the pan is an intregal seal plate and can be reused if not damaged.
Denny

[DmaxProf]

Thanks for the replies. I forgot to ask how much transmission fluid I should expect to add after I finish draining the old. If I'm not going to use synthetic, any recommendations as to brand?

You can probably tell I have never tried this before, but it seems doable even for a novice like me.

[jbplock]

Originally posted by DmaxProf:
..I forgot to ask how much transmission fluid I should expect to add after I finish draining the old. If I'm not going to use synthetic, any recommendations as to brand? The spec is 7.4 quarts for draining the stock pan. Topping off a new spin-on filter prior to installing takes 8-10 oz. So, two 1 gal jugs should do it.

I flushed & filled my Alli with Mobil-1 ATF but if I were using a non-synthetic I'd consider Penzoil Dexron-III ATF.. It's available at Wal-Mart in 1 Gal jugs ... It also carries the latest Dexron-III "H" spec certification. I used it recently when changing the fluid and filter in my 04 Impala.

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[DmaxProf]

I really appreciate the helpful information. Thank you.