Looking for advice with an Eaton RT-7608LL problem

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by FirkusTruckingco, Apr 24, 2024.

  1. FirkusTruckingco

    FirkusTruckingco Bobtail Member

    Apr 24, 2024
    First time poster here, lots of information here but I’ve searched for issues with the Eaton 8ll and haven’t found anything on this particular issue.

    I’ve got a rt-7608ll in a tandem dumptruck with the 8.3 Cummins in it. We had an issue last year where the snap ring broke off in the trans and it was hanging up in 8th gear when trying to down shift…pulled the trans and took it to be fixed. Got it back and all has been great for I’d say 4000 miles or so until today.

    hauling dirt on a short haul mid day,put the truck in fourth and heard a strange rattle/faint dull grind and it went away, get to drop site and go for reverse…no reverse. Try for reverse low and it engages but I hear that dull rattle/grind noise faintly. Engage high side reverse and same thing, works but the noise is there aswell.Check normal reverse gear again and nothing still. What gives? Drove the truck an hour back to the yard and everything was fine other than that little rattle/dull grind from a take off but then goes away. Im thinking maybe another snap ring failure but was wondering if anyone has any ideas other than that, im not terribly familiar with this transmission and their “nuances” so im stumped on what it could be any help would be appreciated thanks!
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  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

    May 2, 2021
    Hard to say what it is. Since there was no reverse, I would say either the sliding clutch in the snchro wasn't fully engaged, the sliding clutch for reverse wasn't fully engaged, or a broken snap ring.

    I would probably drop the oil and PTO or PTO plate and see if you can get far enough back to touch reverse. If a snap ring is broken it will have considerable movement forward and back, basically sloppy.

    Also watch the mainshaft while someone mainpulates the shifter for any movement. Possibly a broken snap ring on the back of the accy drive gear.
    Last edited: Apr 24, 2024
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