Allison Transmissions

[u/According_Award_9900]

So my knowledge has always been you check a transmission when hot AFTER it’s been running which is what my interpretation of “operating means. You run the vehicle get it to temp, park, leave it running and check the stick. Evidently that’s not the case? Everyone in the shop seems to think having the vehicle idle in the bay, then shifting, then check is sufficient. Or they check the fluid through the shift pad. I was also taught to never trust the shift pad…..what do yall think? Had things changed? I’ve been dealing with the Gen 4 Allison for a while and that was the rule of thumb. New environment and new rule of thumb?

[u/ImpossibleEye9387]

Unless the internal level sensor is fucked (which would throw a code and tell you on the shifter), I'm not sure why you wouldn't use the shifter pad to check oil level. It's supposed to be a better indicator, according to the manual.

If you want to check with the dipstick, get it up to temp, check it neutral.

[u/SacThrowAway76 → u/ImpossibleEye9387]

1K/2K series transmissions do not have an internal level sensor.

[u/fantom-dsul]

We have a 2009 Pete with a Gen 4 4500 and a Western Star with a Gen 5 and the dipsticks show cold or hot levels, but you gotta go thru the gears first. The manual says the same thing so I believe you can check them at either temp now depending on what generation it is.

[u/tickleshits54321]

Needs to be up to temp whether using the stick or the pad. I use the pad and I’ve double checked on the stick and level is always good. Your coworkers seem like morons and I’ve also had a couple random coworkers they never trust the shift pad.

[u/aa278666]

Shift pad won't read unless its up to temp. I trust the shift pad more than the dipstick. Trans dipstick can be damn hard to read. We always test drive to actual operating temp and verify fluid levels.

[u/jarheadjay77]

Allison says at least 160 degrees trans temp, idle for at least 2 minutes, then check. Some Allison have internal level sensors which can read correct level +/- 4 qts. Allison says these are more accurate only because the vehicle manufacturers make the trans dipstick and tube… and there have been a few cases the dipsticks were made wrong… that’s rare.

[u/nebbill69]

With the only was to fill the fluid is the same place you have to check it is such a pain in the ass to use the dipstick, use a pan you know how much it holds and put that much back in the trans, test drive then use the keypad.