Revo rear Diff problem - Chitown R/C - Chicago's Largest RC Car and Truck Community

son1cn · (#1 (**permalink**))

After bashing today at busse, my revo's rear diff was acting wierd and making a grinding noise and not getting power to the back wheels. After taking the back end apart to get to it, i took out the old oil and inspected the diff, and i saw no broken teeth or anything. Now i don't know what to do, and i need some new diff fluid. What kind of diff fluid should i get and what should i do to try and fix the problem with the grinding i cannot find.

Casketman · (#2 (**permalink**))

Check the bearings? Although that wouldnt be the reason why the rear is not getting the power.
Stock is 30k,so if you felt fine with that before,then stay with it.

To find the problem. I would just backtrack. Start at the hubs and work your way to the diff,then up to the trans. Check gears,bearings,housing. All of that.

son1cn · (#3 (**permalink**))

where can i buy 30K oil? does al's have it? i'm gonna go there this weekend so if they do i could get it then, unless it is cheaper online.
i checked the bearing, no problem with them at all

Casketman · (#4 (**permalink**))

I never had diff problems unlike other people that I know. So I might be the last person to give diff advise lol.
Diff oil is not hard to find. So you should have no problem

Ponch · (#5 (**permalink**))

Chech the diff outer case. Check the ring/pinion gears.

son1cn · (#6 (**permalink**))

i checked the outer case, it is fine, and so are all the bearings and pinion gears. i really don't know was is going on, so i will try to acquire so diff fluid tomorrow and see if that fixes it.

DAVEC-NITRO-RS4 · (#7 (**permalink**))

Check the transmission as well.

son1cn · (#8 (**permalink**))

checked the trans, no problems except the spur gear kind of worn... gonna get some diff fluid and new spur gear tomorrow.

DAVEC-NITRO-RS4 · (#9 (**permalink**))

I used 10k in the rear diff on mine and it really helped it turn quicker (until the damn engine dropped the rod). 30k in the front.

Casketman · (#10 (**permalink**))

I might have to try that. Dont think I have 10k tho. I need some anyway.

kevinF · (#11 (**permalink**))

did you have any diff fluid in there??

DAVEC-NITRO-RS4 · (#12 (**permalink**))

Did you make sure the rear center drive shaft is still good? If it splits you could lose drive.

son1cn · (#13 (**permalink**))

yeah, 30K is stock, but when i opened it up it was a black goo and looked like it wasn't doin much. How do you get the goo off the sides of the diff? i tried denatured alcohol but to no avail

and yes the rear drive shaft is good, it has no cracks or anything

DAVEC-NITRO-RS4 · (#14 (**permalink**))

I swear Traxxas uses 30k black goo, not silicone fluid. That's how lots of them look, I've heard. The manual claims 30k fluid but I dunno....nitro spray and a toothbrush gets it off.

SLOW REVO · (#15 (**permalink**))

Soak them in a bowl of gas,

Tex · (#16 (**permalink**))

just want to make sure......you did take the diff cup off the ring gear and check the spider gears? that's what always was wrong when my revo diffs had a problem.

Also replace the outer main diff case and inner diff oil cup. They both wear over time and the slightest wear on those will cause diff failure.
Beleive it or not, where the main outter diff case sits in the bulkheads wears also over time and causes excessive diff case movement during operation.

I would think about changing the bulkheads, and buy a complete new diff from ebay, it'll be like $20 shipped for the diff. Then you won't have another problem for 3-4 more gallons, you won't even have to worry about it.

son1cn · (#17 (**permalink**))