Overdrive mod question.

[philg]

I have done the overdrive mod with the Traxxas #7079 pinion.
When I turn the wheels(drive shaft is not connected), it spins well except there is an area where it tighens up a bit.
Is this normal?
Will it bed in over time?

cheeers

[JeremyH]

It will.

With that pinion, it is very important to make sure the mesh is tight and that there is no in/out play with the pinion or side to side play with the ring gear. The teeth on the traxxas gear are a different shape and will skip on the ring gear is they are not properly meshed. If they are not, use some shims to get them correctly placed.

[philg]

Originally Posted by JeremyH

It will.

With that pinion, it is very important to make sure the mesh is tight and that there is no in/out play with the pinion or side to side play with the ring gear. The teeth on the traxxas gear are a different shape and will skip on the ring gear is they are not properly meshed. If they are not, use some shims to get them correctly placed.

Thanks for the info mate,just checked the tolerances and all looks good.

[89redranger]

I had the same problem when I did mine. Turns out that when Losi cast the ring gear piece of the diff carrier, they didn't cast some of them completely true. Mine had a little wobble to it that cause inconsistent meshing. When I installed the Traxxas pinion it amplified the problem ten fold. I swapped my rear diff into the front, put the wobbly diff in the rear (where the tolerances are a little looser with a stock pinion), and it "fixed" the problem. Now there is a tight spot in the rear diff, but it's not near as extreme.

One of these days I'll pull a diff out of one of my parts rigs, but for now it doesn't really bother me. You can't hear it, see it, or even notice while driving it with the wobbly diff in the rear. The only time I notice it is when I'm turning the wheels by hand.

Recently I've added lengths of stainless tube inside my diffs and, if cut to the right lengths, you can use them to adjust the gear mesh. Need the mesh tighter? Make the opposite tube a hair longer so it pushes the diff inward. Do the opposite if it's too tight. Watch that BOTH tubes don't ride firmly against the diff. They should be smooth on the ends as well. If you don't watch these you'll end up with an axle with so much drag you won't need your drag-brake!

[JeremyH]

Originally Posted by 89redranger

Recently I've added lengths of stainless tube inside my diffs and, if cut to the right lengths, you can use them to adjust the gear mesh. Need the mesh tighter? Make the opposite tube a hair longer so it pushes the diff inward. Do the opposite if it's too tight. Watch that BOTH tubes don't ride firmly against the diff. They should be smooth on the ends as well. If you don't watch these you'll end up with an axle with so much drag you won't need your drag-brake!

The same can be accomplished by putting large shims on the back side of the ring gear (between the gear and the bearing). This will push the teeth toward the pinion gear.

[philg]

All good advice guys,thanks.

[ram_tough]

Originally Posted by JeremyH

The same can be accomplished by putting large shims on the back side of the ring gear (between the gear and the bearing). This will push the teeth toward the pinion gear.

Ive had mine set-up the same way for at least 2 seasons now with the stock and Traxxas pinions with great results.

[bigjay1973]

i shimmed my ring gear and and never had a single issue...one of the best mods you can do.

[tunnalram]

we always just run em with a drill for couple minutes. breaks it in nice and smooth mesh