Allison MD3060

[oldcobia]

Another Allison MD3060 question. When transmission would downshift from 5th to 4th while slowing down it would sometimes be a little harsh. After changing to synthetic it is really harsh. Is this just a coincidence and TPS going bad or can it have anything to do with different fluids. Thanks

[wolfe10]

Really doubt it has anything to do with your filter/fluid change.

At least on three different DP's with that transmission, changing fluid did not lead to harsher shifts.

Have you used your shift pad to check for DIAGNOSTIC CODES? Any?

[oldcobia]

Tried. Used directions on YouTube and doesn’t work as shown. Up and down arrow goes to oil then again shows d1. Push again shows d2 and so on. Goes to d6 then back to NN.

[wolfe10]

Tried. Used directions on YouTube and doesn’t work as shown. Up and down arrow goes to oil then again shows d1. Push again shows d2 and so on. Goes to d6 then back to NN.

Yes, depending on year/model of Allison, the first push of the up and down arrows will bring up OL (oil level).

The second push will bring up d-1. If the d-1 is followed by -- there are no diagnostic codes= no electronic problems.

If the throttle position sensor (sends throttle position info to transmission) is out of adjustment, it can cause shift issues (i.e. mechanical cause).

[oldcobia]

That’s exactly what mine showed. I’m happy no codes. Very much appreciate your input. Now have to google TPS adjustment. Thanks

[oldcobia]

Decided to recheck for any codes and while going through all the d 1-d-6 it would go back to d-1 but would skip d-6. So after checking d-5 it would go back to d-1. Still no codes. Thanks

[wolfe10]

Decided to recheck for any codes and while going through all the d 1-d-6 it would go back to d-1 but would skip d-6. So after checking d-5 it would go back to d-1. Still no codes. Thanks

If you get d-1 and - - (blank blank) that means there are NO CODES.

If there are codes as soon as you get to d "whatever" and - -, there are no more codes.

[oldcobia]

Thanks again.

[oldcobia]

In previous post I decided to use the o-rings and gaskets that came in my filter kit. Even though I was supposed to use the square rings that came off and the age of transmission. All worked great. But in my anal wisdom I decided to order square o-rings and put them in but I left gaskets in place. Mine did not have gaskets when I took plates off. I like to put things together like they are supposed to be. Seems to be a little seeping now but not sure until I drive it some. Had to replace nearly one gallon of oil to bring back up. Heading to Texas in 4 days. Do I think too much? Should I just have left it alone with wrong o-rings?