DM685 with maxitorque 4(plusLo) speed banging

[biffidun]

Hi guys, here is my problem. I can drive all day as long as I don't stay in 4th (top gear) for more than say 5-10 minutes. If I stay cruising for too long then a rythmic banging starts to come from the transmission, which progressively gets louder and then the truck starts to hesitate with each bang. All I have to do to fix this (temporarily) is to come to a complete stop and start up again. As I get rolling through first gear there is a clunk and then all is well for another 5 minutes are so.

I have checked and added gear oil to the transmission (not sure how much to put in though) and I have added gear oil to one of the diffs in the rear. I put some Lucas in the transmission thinking it was not getting proper lubrication up at the top on the 3rd 4th gear axle. No significant change, in fact I might say that the problem presents itself sooner with the Lucas in there.

I removed the top plate of the transmission but could not see anything obviously wrong.

Any thoughts?

[Rob]

Hi guys, here is my problem. I can drive all day as long as I don't stay in 4th (top gear) for more than say 5-10 minutes. If I stay cruising for too long then a rythmic banging starts to come from the transmission, which progressively gets louder and then the truck starts to hesitate with each bang. All I have to do to fix this (temporarily) is to come to a complete stop and start up again. As I get rolling through first gear there is a clunk and then all is well for another 5 minutes are so.

I have checked and added gear oil to the transmission (not sure how much to put in though) and I have added gear oil to one of the diffs in the rear. I put some Lucas in the transmission thinking it was not getting proper lubrication up at the top on the 3rd 4th gear axle. No significant change, in fact I might say that the problem presents itself sooner with the Lucas in there.

I removed the top plate of the transmission but could not see anything obviously wrong.

Any thoughts?

There are magnets in the side, and bottom of the transmission; these should be checked for "chunks". Also I would pull the side magnet in the front drive axle as you could have a cam and peanut issue developing.

Rob

[biffidun]

Thanks Rob. I checked the magnets on the tranny and other than a fine metal sludge nothing big. The drive axle may just be it. I've never touched wedges before, is this a scary thing or not too bad? I know they should be replaced as a set, but is there anything I should know? I do not have air lockers in the back fwiw.