Allison transmission creep

[Scarlett]

I talked to 2 friends with Detroits with Allison transmissions and both of them said they solved their creeping problems by going to 30 weight oil. My mechanic said the Allison's will run just fine on 40, 30 or even ATF if need be. Have any of you experienced creeping and found it went away with 30 weight oil? Thanks , John

 

[Pascal]

Not sure what you mean by creeping. Do you mean slipping? Slipping (rpm going up for no reason) is usually a sign of low oil pressure and or low level. It is usually accompanied by a 1 to 2 sec delay when engaging forward gear. Normally bringing level back to where it should cures it

 

[Scarlett]

Thanks for reply, no slowly turning in neutral.

 

[MikeP]

Often that is just a function of the shifter being out of adjustment. Disconnect the shift cables from tranny shift lever at the rear of the transmission and ensure the lever is in the neutral detent. See if the creeping stops. One of our trannys used to do the same thing and I found if I wiggled the helm shift knob a bit when I went to neutral to ensure the transmission lever was precisely in neutral, there was no creeping. If I just shifted to neutral without wiggling, odds are it would creep. Resistance in the cable/other parts of the system can result in the transmission lever not being exactly in the detent position even though it feels like it is from the helm. Also, some tranny will creep when cold in neutral but not when they are at operating temp.

The DD service manual says the tranny should use the same oil that's in the engine so that tends to leave some leeway re specific weight since DD specs 40 or, in cold weather, 30. HOWEVER, no engine uses ATF for lubricating oil so even though I SUSPECT it would work OK, I'd leave that for someone else to try and report how it worked over 500 operating hours before I would consider trying it.

 

[SEVEN]

Well stated Mike. Dead on.

 

[SKYCHENEY]

Mine creep cold. I went to 30wt and saw no difference. Once they are warm the creep stops.

 

[Scarlett]

Thanks everyone, Mike, that was a good suggestion because I did just put in new shift cables and I was carefull on the adjustment but they might have settled in and need another slight adjustment, will try that. Sky also a good comment as weather here today was colder than it has been for months and I started up without my block heaters. John