durallymax
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A very important part of your trucks maintenance schedule that is often overlooked. This write up will walk you through it all.
The Allison transmission is unique in its own way compared to other automatics as it has two filters, both an internal sump filter and an external spin on filter. According to Allison and GM you will never need to change the Internal filter until you rebuild your Allison and with the cost of rebuilding an Allison many just opt for a new transmission anyways. However the spin on filter does need to be changed every 12,000 miles to keep your tranny clean and happy. Also if you just bought your truck it’s a good idea to do this right away to start fresh as you never know what the previous owner did. Not changing the spin on filter can cause awkward shifts and if it gets plugged it can even burnt up clutches. So its cheap insurance. I would recommend getting one from the local Allison parts counter. They have the best price. Gm rapes you for one. You shouldn’t loose much fluid. If you want though you can pick some up you’ll need about a quart max. For the 5spd it needs to meet Dex III standards, for 6spd it needs to meet Dex VI. Also while you are getting your filter you may want to grab a new filter magnet as it is common for these to be missing due to dumb mechanics or dumb quick lube people. Plus I tend to just use a new one anyways as they like to slip out of my hands when cleaning them. If you drop them from like a foot off the ground they will snap. They’re maybe 3 or 4 bucks from Allison
1.[FONT="] [/FONT]Filter wrench or filter pliers
2.[FONT="] [/FONT]Small drain pan
3.[FONT="] [/FONT]New Spin On Filter
4.[FONT="] [/FONT]New Magnet (optional)
5.[FONT="] [/FONT]Ouart of ATF
1.[FONT="] [/FONT]Roll under your truck with the filter wrench/pliers, drain pan, and filter with new magnet installed.
2.[FONT="] [/FONT]Spin the old filter off, these are very tight so they take some muscle.
3.[FONT="] [/FONT]Once its off lube the o-ring on the new filter with some ATF and spin it on. Once it contacts the case spin it at least one more full turn.
4.[FONT="] [/FONT]And now your done. Get the trans up to temp(150+) then shift it into reverse, then drive then park and go out and check the fluid level to make sure it is still in the right area. If you need to add any you add it through the dipstick tube.
5.[FONT="] [/FONT]Now your done. Pretty simple.
Here is a picture of the filter. Its the little red one.
Here is a picture of the magnet.
How To Change Your Allison Spin On Filter
What You Will Need
2.[FONT="] [/FONT]Small drain pan
3.[FONT="] [/FONT]New Spin On Filter
4.[FONT="] [/FONT]New Magnet (optional)
5.[FONT="] [/FONT]Ouart of ATF
Procedure
2.[FONT="] [/FONT]Spin the old filter off, these are very tight so they take some muscle.
3.[FONT="] [/FONT]Once its off lube the o-ring on the new filter with some ATF and spin it on. Once it contacts the case spin it at least one more full turn.
4.[FONT="] [/FONT]And now your done. Get the trans up to temp(150+) then shift it into reverse, then drive then park and go out and check the fluid level to make sure it is still in the right area. If you need to add any you add it through the dipstick tube.
5.[FONT="] [/FONT]Now your done. Pretty simple.
Here is a picture of the filter. Its the little red one.
Here is a picture of the magnet.