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I have a 4x4 brontosaurus I built from just a rolling chassis. Running a 3250kv hobby wing motor with 10t pinion on 3s..I have 1mil lube in diffs and diffs are also shimmed...everytime I take it out i strip both diffs in just five minutes....any idea why i keep destroying diffs?..no binding and upgraded diff housing to aluminum to get rid of flex...can't figure out what the issue is...any help?

bill_delong

3S on 3250KV is insane for that rig, I would definitely check the mesh inside the gearbox and add shims to one side of the bearings to ensure minimal backlash. Also consider running on 2S, it could be that you're over powering the car beyond what it was designed to handle

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It's 1/10 scale pretty heavy

suburban_hooligan

had to google "4x4 brontosaurus" it's an HSP. HPS is a lower grade entre level brand. and you're putting power in it that high end brands would have trouble with. like bill said, you're over powering the car. only thing you can do is lower the power. run a 2s pack, and/or get a less powerful motor.

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It comes with 3300 kv motor stock...didn't think a 3250 would be too much...10t pinion could be an issue?

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Should I go with higher kv motor?

bill_delong

which 3250KV motor are you running?

The motor needs to be a 3650 can, if it's any larger than that, then you are pushing too much torque, no matter what I would limit to 2S

If you want to run 3S then consider upgrading to ARRMA

suburban_hooligan

if it came with a 3300kv motor your 3250kv shouldn't be an issue unless it's a 4pole. if your 3250 is a 4 pole its making significantly more torque than the stock motor did.

here's question, does the truck have a slipper clutch of any kind? 4x4's typically don't but figured id ask anyway sense im not super familiar with your truck.

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It's a 3652 hobby wing quikrun...it does not have a slipper clutch

suburban_hooligan

if it's this one: https://www.amainhobbies.com/hobbywi...04400/p1499918
that's your problem. it's a 4 pole. and you're running 3s. think of a 4 pole as a turbo diesel engine, it's torque city!
im running a 3800kv 4 pole Castle motor on 2s in an HPI Savage XS and break drive pins and strip plastic wheel hexes constantly. the truck will do standing start backflips on a high traction surface and the truck has a slipper clutch in it.

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That's it...was snapping dog bones at first then I found some decent ones and then started stripping diffs...I'll try only 2s once I get diffs rebuilt again

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I had a 5200kv motor I started with but had extreme cogging so I figured wasn't enough torque so I went with the hobbywing..I guess it's too much

suburban_hooligan

all the cogging iv experienced was because of gearing. if i geared up for high speed id loose bottom end and it would cog. a work around is switching to a sensored motor. i had bad cogging with my RC10 Worlds Car when i had a 17.5 sensorless motor in it. i put a sensored 17.5 motor in it and went away.