Differential Gear Noise...

[BadWagon]

Hey guys,

I received my Wraith Kit last night and started assembling the axles. The front axle is good to go, the dif gears are quiet, smooth and feel great.

The rear is a different story. The gears are not meshing properly. I broke it down, reassembled, tore it down again and can't seem to get the gears aligned properly. You can feel how poorly they are aligned when you spin the pinion or axle.

I searched (yes I really did. I may be a noob on rcc, but I know how to use the search) but I couldn't find anything on solving the issue. A link to a thread where this is discussed, or just some info on how to properly set up the differential would be super helpful.

thanks in advance fellas.

 

[SkaldidDog]

One benefit of your Wraith is that the front and rear axles are identical. Tear the front one completely down and spread out all of the parts side by side with the similarly disassembled rear axle. Meticulously compare the fit and finish of all of the components. The problem should become evident. If not assemble the front one several times with components from the rear until the front one has the same problem the rear did. Note the part that transferred the problem from front to rear. Or you can scramble the parts and it may be that two parts on the rear are slightly off and separating them front/rear may eliminate their additive problems.

J

 

[BadWagon]

Thanks SkaldidDog I'll try that. I have the Hot Racing Unibody SHD Differential Lockers on order which should be here today, so I have to tear down the axles anyway.

Cheers,
B

 

[wwmkwood]

Alot of the kits had an issue with the rear axle binding

http://www.rccrawler.com/forum/axia...e-short-shaft-issue.html?highlight=axle+shaft

 

[Dualdigger]

When I built my Wraith I had the same issue. I did what you did and searched for the answer but never found it. It wasn't the axle binding issue, it turned out to be poor meshing of the ring and pinion. I solved it with some shims, to be honest the front went together smooth and the rear was a little rough(even shimmed) from new and I just ran it. Now the front axle is sloppy as sh*& and the rear is like butter...go figure.

 

[BadWagon]

Alot of the kits had an issue with the rear axle binding

http://www.rccrawler.com/forum/axia...e-short-shaft-issue.html?highlight=axle+shaft

Thanks bud. I read that thread... It's not binding, the gears aren't meshing... but hey, I'll reread that thread and see if I missed something.

When I built my Wraith I had the same issue. I did what you did and searched for the answer but never found it. It wasn't the axle binding issue, it turned out to be poor meshing of the ring and pinion. I solved it with some shims, to be honest the front went together smooth and the rear was a little rough(even shimmed) from new and I just ran it. Now the front axle is sloppy as sh*& and the rear is like butter...go figure.

Yep, that's what I've got going on (at least I think I do). hmmm... strange that the front got sloppy and the rear is butter. Did you shim the pinion or the bearings on either side of the dif to move it in or out?

Thanks for all the input fellas!"thumbsup"

 

[Dualdigger]

I found the ring gear was too close to the pinion and it caused the binding, I used very thin plastic strips to shim around the bearings(moving them slightly away from the pinion). I need to go in there and check it over, I'm pretty sure the slop in my front axle is in the locker, but you've got that covered with HR lockers.

 

[monkeymagic9]

My two-cents:
Had to solve a similar issue.. slipped a thin washer over the input shaft (pinion's shaft) on the outside of the axle then used a small pick to align the hole in the shaft with the hole in the driveshaft to insert the pin. no more grind. Same assembly a few packs in started to feel real sloppy so I removed the shim and now it's perfect as it should've been in the first place.

If you take the driveshaft off and push in on the input shaft you can get it to bind. Controversely, you can pull it out and turn it and it'll feel loose enough to skip. I'm guessing it's designed to go together and not matter as it'll float around in the middle of the two extremes, but apparently some manufacturing tolerances or assembly variances come together in a handful of axles and cause chaos.

Please note: if you shim it and it is too far out.. it WILL tear something up eventually. Maybe not the first good chance it gets but probably at a time no less inconvenient. If it just feels a little too tight it'll probably be okay, just keep an eye on the wear and grease it when it needs it.

 

[BadWagon]

I'm gonna try to shim the ring gear first and if that doesn't work I'll give monkeymagic's solution a shot. I've come down with a nasty cold so it'll be tomorrow before I can work on it again.

Detail Oriented work and night time cold meds don't go too well together.

Thanks again fellas.

 

[BadWagon]

This morning while drinking my coffee and returning some work calls I broke down the rear axle again. The gears simply aren't meshing. There seems to be some play in the pinion and the input shaft (pinion slides up or down on the shaft) but no matter how I position the ring gear or pinion it's not aligning correctly.


I tried to shim the pinion, but that caused it to bind. I think I'm gonna need to break down the front axle and see what is different between the two.

However, when I flip the ring rear to the wrong position (the long axle side) I can get it to mesh better. Not 100% perfect but really close.

Thanks again for the help guys.

 

[diesel kawboy]

Don't worry about it. Just pack it full of grease, slap a brushless beast on it and run it! Everything will mesh eventually.

 

[BadWagon]

Lol. Well I thought about it, but I did that back in the day with my fox and stripped the whole gearbox out. It's meshing so poorly it wouldn't last a full pack. It's so damn LOUD and rough that running it as it is just isn't an option. I'll figure it out

 

[BadWagon]

Well I had time last night after getting all the boys to bed to work on the axles a bit more. The sloppy pinion was the culprit, and I just took the easy work around. I placed the sloppy pinion in the front axle as it meshed ok with the ring on the long axle side. Put everything back together with a heavy dose of assembly lube. It's acceptable, not meshing as well as I would like. so I tweaked the bearing cap bolts a bit until I was able to get it almost dead on. The weird thing is that it seems fine, but you can feel resistance at one point in its rotation. I took the axles back out and the issue went away. Reinstalled the axles but the rough spot was still there. Has anyone had axles from the wraith kit which were not true right off the get go?

It seems to me that the differential is good now, but the long rear axle is just a tad untrue an tries to deflect the diff. It's ok to run it, as its not horrible, just curious if anyone else has seen this.

I got the links and shocks assembled and mounted on the axles last night so I'm cruising along now. Should be ready to drop in the electronics as soon as they arrive. Woot!

Thanks again for all the help guys.


Cheers.

 

[silverjeep]

I am having the same issue with the rear axles ring gear and pinion meshing. They are aloud and also binding. I took the rear axle a parts and it felt pretty smooth until I put the bearing caps on. Now its tough to turn and the gears are not meshing. This is a new kit straight out of the box. What has been the best fix for this. I have a bunch of experience with setting up gears in jeeps and offroad buggies but RC cars are new to me.

Adding ring gear spacer?
Pinion spacer?
Swapping out pinions from the front axle (which is smooth)?

Thanks for the input!

 

[diesel kawboy]

You could swap gears out and then it would help narrow down your issue.

 

[ZippoMan]

I am having the same issue with the rear axles ring gear and pinion meshing. They are aloud and also binding. I took the rear axle a parts and it felt pretty smooth until I put the bearing caps on. Now its tough to turn and the gears are not meshing. This is a new kit straight out of the box. What has been the best fix for this. I have a bunch of experience with setting up gears in jeeps and offroad buggies but RC cars are new to me.

Adding ring gear spacer?
Pinion spacer?
Swapping out pinions from the front axle (which is smooth)?

Thanks for the input!

Your bearing caps are too tight in my opinion. That seems to be common with the stock plastic junk!! Buy some STRC or other aluminum caps and you shouldn't have a problem. Just my opinion. "thumbsup"

 

[Kelly H]

Don't forgot to have the driveshaft installed, with out it the pinion gear can walk into the ring gear, and cause binding.

 

[transambill]

However, when I flip the ring rear to the wrong position (the long axle side) I can get it to mesh better. Not 100% perfect but really close.

Thanks again for the help guys.

This statement makes me think it's the rear short shaft issue.

Did you have any trouble getting the axle shafts to slide into the locker far enough to get the rear lock outs slid onto the housing and have the mounting holes in the axle housing and lock outs line up?

How thick are the axle shaft flanges that butt up against the locker, can you post a pic of the rear axle shafts?