DESC210 - New Build Gear Diff MM4 no drive Slipping

[raymondkerr]

Built my DESC210 last week with the kit ball diff and ran the car for a couple of heats adjusting the slipper to suit. Running with a speed passion 8.5, after a couple of runs, I lost drive and no amount of slipper adjustment would work, decided to rebuild the ball diff carefully as per the durango guide, but with no success.

Decided to buy a Gear diff and built as per durango guide and installed today in Mid Motor 4 Gear, carefully checking that all the gears and layshaft where installed correctly and that nothing was missed. The diff when installed in the gearbox turns perfectly free by hand, when installed in the car, I get very little to no drive, sounds as though the slipper is very loose, even when tightened up the slipper still bad slips and there is next to no drive. I have been careful to check that the slipper pads/plates are installed correctly and that the slipper screw and spring with washers are installed correctly and in good condition, but nothing appears to be working. The kit is brand new and has only been run for a couple of heats.

Is there anything obvious that I may have missed, I have had the gearbox and slipper assembly stripped out twice with no success, haven't tried any other motor config as I really want to run MM4.

[graveltrap]

Possibly a squashed crush spacer on the layshaft, due to over tightening the slipper, but I thought the part had been upgraded by Durango.

[raymondkerr]

after doing a bit of research on the forum, I decided to check the layshaft spacer and bearings, both are still in perfect condition, bearing works fine and the spacer doesn't appear to have any damage at either end. I've looked again closely at the manual to ensure that I haven't made any mistakes, and then re-assembled, but still the problem persists. I even replaced the slipper nut for a new one. When I gently apply throttle whilst hold one of the rear wheels, the spur gear hesitates then starts to rotate, when on the bench gentle throttle does appear to work and both wheels start to move, but when on the ground with load, I just get lots of slip. I'm reluctant to tighten the slipper much more than about 4-5mm in from the end of the screw, tried slowly applying throttle and then turning the screw in until I get bite, but its not tightening. The slipper pads have a slight rub on both sides as I've tried to use both sides of the pads, but they are far from worn, the pads on my 410 are way worse and still perform ok.

I'm completely puzzled at this point, not sure where to go from here and what to try next. ???

[OneKiwi]

Just a thought is the motor ok? Can the rotor be buggered? Are you able to test another motor or test the motor in another car.
Does the motor spin up ok?

Try with other slipper pads, get the thicker ones like schumacher or AE HT ones. What spur are you using? Stock or another brand?

Id replace the little bearing as well, anyway just to make sure.

Are you still using the gear diff?
Are all idle gears whole?

[jo90]

Check you havent screwed through the gearbox long screws and they are protruding out and catching on the back of the slipper. A guy at the club last week had done this and it basically jams the gearbox.

Put about 1-2mm spacers on the 3 long bolts before you screw them in and through into the motor mount plate, then check all this again.

[ekt]

After reading all the things you've already checked, I would try put a spacer on the layshaft before you put the slipper plates on.