Allison w/sloppy shifts?

[Mark Rinker]

Fourth snowfall here in Minnesota - last night noticed some 'late' or 'loose' engagement when shifting from R to L1, occasionally from L1 to R.

Best way to describe the problem would be a loose torque converter, or loose clutch, allowing a momentary 'slip', resulting in slight rise in RPMs, and a soft 'bump' when the gear engages. Happening about once in 15 or 20 shifts, when it does occur, it tends to repeat itself in groups before disappearing to normal tight gear engagements.

I don't recall this ever happening in the first three snowfalls / snowplow sessions. Snow was not particualrly heavy or wet. Always brake to a complete stop before reversing - and with brake firmly engaged to ensure wheel movement has stopped.

One other variable - yesterday did a 7qt drain and fill with new spin-on filter, and my buddy used Amsoil synthetic ATF...

Go back to Dextron VI and see if it disappears? Damn it would take a full 18qt flush...expensive test. Defective filter? It was an OEM Delco.

Thoughts?

[cowboywildbill]

I'm not a trans tech, but it sounds like maybe a solenoid hanging up. Or a piece of dirt in the valve body. Just a guess.

[dually2002]

Did you use the Amsoil ATF rated for the Allision? I beleive its called Torque Drive and it doesn't come in quart bottles.

[Mark Rinker]

I called my buddy (who has a new repair/service shop) and he assured me that the Amsoil was synthetic and compatible with Dex-VI. I was there when it was added, came out of a huge 10qt square 'jug'. I will double check on Monday at his shop.

We decided to run the truck as-is, seeing if it appeared during normal driving and tow duty, or just after repeated reverse/forward shifts that are common during snowplowing with straight blades, i.e. windrowwing (http://en.wikipedia.org/wiki/Windrow).

If the symptoms reappear, we plan to change

Spin-on filter, in case there is a defect causing restriction to flow;
All 18qts of tranny fluid back to Dex-VI...in that order.


Also, I never correllated the lazy shifts to trans temps, but I am certain that it was when the tranny was at peak temps, but never observed anything more that 195F temps at the DIC.

[Jake99Z71]

Amsoil ATL is the correct fluid that is compatible with Dex-VI fluid. Not saying this is causing the problems with your shifts.

[Kennedy]

I wouldn't run anything but Dex III or Transynd myself. Transynd is my first choice. The regular synthetics seem to have too much friction modifier and can reduce clutch holding capacity. This is something we saw quite some time ago already.

The issue that you describe is likely just normal delayed apply. My 2005 does this some times too. Just need to be patient and wait for it to drop into gear (Apply clutches) completely