Front Diff problems

[Midwest Boss]

I am having probs with my front diff gearbox, i rebuilt the diff and shimmed it , gear mesh is good, reset the grub screw , but for some reason my front wheels stop spinning when i go run it, its like the diff is slipping from the gear in the diff housing. Please help if anyone has an answer!

 

[TBuggy]

Have you opened up the diff case and looked inside?

 

[cordell12]

open the diff itself. looks like you need some grease in the diff housing, you diff gears inside the cup may be shot. can you turn the outputs on the diff itself?

or the input cup that the driveline hooks too, could have loosened up and it just spinning.

 

[Midwest Boss]

Have you opened up the diff case and looked inside?

Ya the diff is good, spins freely, that pic is the inside of the gearbox, i think i lost a bearing or it got jammed in the gearbox. There should be a bearing on each side of the gearbox/diff housing and it looks like i lost one, let me know if you think thats it

open the diff itself. looks like you need some grease in the diff housing, you diff gears inside the cup may be shot. can you turn the outputs on the diff itself?

or the input cup that the driveline hooks too, could have loosened up and it just spinning.

I rebuilt the diff itself , its good and spins freely, i think i lost a bearing in the housing , look at the pic , looks like im missing a bearing behind the gear?

 

[TBuggy]

Is there a ton of slop in the pinion in the pic? Maybe you are missing a bearing. There is supposed to be two bearings for the diff pinion. Hard to imagine though a bearing blowing out without seeing some sort of pieces?

 

[Midwest Boss]

Ya there is alot of play on the pinion so i reset the grub screw and still had the same problem , i think the bearing burrowed into the diff housing, because i cant even see it right now , im going to tear it down tonight, i bet i need a new diff housing and bearings , the pinion gear looks fine just pry needs some grease , thanks man for responding , always helps!

 

[cordell12]

Ya the diff is good, spins freely, that pic is the inside of the gearbox, i think i lost a bearing or it got jammed in the gearbox. There should be a bearing on each side of the gearbox/diff housing and it looks like i lost one, let me know if you think thats it

oh yeah, there should be 2 bearings. one inside and one outside.

 

[Midwest Boss]

oh yeah, there should be 2 bearings. one inside and one outside.

Yep i think thats my problem, im going to tear it down and check it out , should be an easy fix , new housing and new bearings, i think my pinion gear is fine , thanks for helping man!

 

[cordell12]

Yep i think thats my problem, im going to tear it down and check it out , should be an easy fix , new housing and new bearings, i think my pinion gear is fine , thanks for helping man!

It almost looks the the inner bearing got sucked into the housing somehow. Maybe the inner bearing failed and the heat melted the plastic and it just sunk into the housing.

 

[RC_User]

yep it's damaged somehow. need a new diff case... weird!

 

[Slevin]

Is that grease or melted plastic?

 

[Midwest Boss]

Is that grease or melted plastic?

Its liked melted plastic

 

[Slevin]

Its liked melted plastic

Lol that is nuts!

 

[Midwest Boss]

Hey fellas, wanted to post an update, i got a new front gear box, bearings and pinion gear, the diff was fine i just added fresh oil and now the front end is spinning smooth as butter, the truck is running great and im back to bashing! Thanks for all the help!

 

[EBaltazar]

Hey fellas, wanted to post an update, i got a new front gear box, bearings and pinion gear, the diff was fine i just added fresh oil and now the front end is spinning smooth as butter, the truck is running great and im back to bashing! Thanks for all the help!

How many packs had you run through the truck when you noticed this issue? Just curious.

 

[Midwest Boss]

Pry about 15-20 packs since i have had the truck. Running 6s with the arrma blx 185 system.

 

[TBuggy]

From the picture you posted above it looks like you could have had more grease in there if what we are looking at is indeed melted plastic. That could have caused the over heating that caused melting/excessive wear to the plastic around the pinion gear.

Not exactly sure on your process but I like to put a nice fat bead of grease all the way around the ring gear before installing into diff-case, after I have already figured out my shimming needs with a dry fit. Now I don't run any 6s rigs either so that could be part of it too...excessive speed and torque usually leads to excessive wear/breaking with just about anything not just RC.