Shaft Turning in Neutral

[jrmccoy]

Gentlemen, I've reviewed the threads. 1980 DD's on the Allison tranny, seems to be dragging clutch at idle in neutral. I can stop it with my hand, but its persistent. Transmission pressure is in low 100's. PO says that there is an adjustment that can be made, either on the linkage or at pump. I've tested moving the small arm at the pump slightly and I can get it to stop if I move it to just the right location, but its a hair trigger and if I bypass it, it starts dragging in the opposite direction. Gears work correctly both ways when engaged, just dragging in neutral.

Oil level in tranny is good, and is really clean, so not concerned about rear seals.

Any thoughts appreciated.

 

[racclarkson@gmail.com]

I'm not a transmission specialist-or any other kind I guess. My ZF BW250 gears both spin slowly in neutral when motors are first started. It's worse in the winter, but it's never fast and hand stoppable like yours. I attribute it to cold oil; mine are 27 liters of 40 wt. I can put units in-gear, cold, and then back to neutral and they generally will stop after that. Or, they will cease spinning after a few minutes on their own. I've never worried about it.

 

[SKYCHENEY]

My M20's have done the same for 13 years and over 1200hrs. Its no worse than it was years ago. I just live with it. Once the oil is warm, they don't move in neutral.

 

[SEVEN]

Same here Sky.

 

[MikeP]

What Sky said - same for our 53.

 

[jrmccoy]

Re: Shaft TurningT in Neutral

Thank you gentlemen...I'll take this occasion to keep an eye on it and do nothing at this time. It is just a new action so I thought I'd ask advice, and I too suspect that if I got out and warmed up the tranny it would stop.

 

[M&MArmenta]

Many times this "creeping" of the shaft can be stopped by a simple cable adjustment. If this does not stop it the likely cause is the selector valve leaking by. The selector valve is what the cable connects to.

 

[MikeP]

As noted, you will probably find that if you move the selector lever on the tranny back/forth a tiny bit, you will find a spot where there is no creep at all, even cold. But even when adjusted properly, the normal slop in the cable can make that spot hard to find with the tranny levers at the helm.

I have found that if I put it in neutral and than wiggle the shift levers a bit while they are in the detent position, the selector lever will usually "find" the position where the creeping stops.