output shaft from diffs gets wobbly.

Nigel · #1 13-08-2011

Well, I know it's bad if the output shafts are wobbly on the differential. But I shimmed them correctly and followed both these posts.

http://www.team-durango.com/blog/200...-perfect-diff/
http://www.team-durango.com/blog/201...box-pro-build/

After I finished building the diffs the output shafts were not wobbly at all. But after running two packs throe it, I can wobble them side to side and up and down.

Nigel · #2 14-08-2011

well i ran it again for about 5 mins today and nothing seems to strip but again it was only 5 minutes.

RC John · #3 15-08-2011

The wobble isn't caused by improper assembly. It's happening because the hole that the outdrive sits in has worn and has more play now compared to when it is new.
I noticed my rear outdrive on the diff case side was wobbling pretty bad, so I replaced the plactic diff case. This help reduce the wobble a lot. But even with brand new parts, there is still some wobble.
I've not had anything break yet because of excessive outdrive wobble, so it might not be anything to worry about.

dpackster1980 · #4 15-08-2011

Quote:

Originally Posted by RC John

The wobble isn't caused by improper assembly. It's happening because the hole that the outdrive sits in has worn and has more play now compared to when it is new.
I noticed my rear outdrive on the diff case side was wobbling pretty bad, so I replaced the plactic diff case. This help reduce the wobble a lot. But even with brand new parts, there is still some wobble.
I've not had anything break yet because of excessive outdrive wobble, so it might not be anything to worry about.

Nail on the head, this is why the diff casings are so cheap. I must admit they should last a while but if you let them go too much the internal gears will destroy themselves.

I recommend them to be changed once a season just in case.

paulc · #5 15-08-2011

I've ran mine for about a year and a half with no problems

BostonNelson · #6 15-08-2011

Dont worry about the wobble. A year and a half with the same outdrives and diff gears without any problems. Knock on wood.

. Still running the 2009 (retro) spec.

Nigel · #7 16-08-2011

like i said again i shimmed them perfectly and i have only ran it for about an 1hr and a half in total so i don't think the diff boxes are worn down.

but by the sounds of what you guys are saying i don't think i have to worry about it

coleman758 · #8 16-08-2011

i re-built my diffs last week, I noticed mine are very much the same.
When the cars all built up if you put your finger on the out drive it moves maybe half a mil' either way.

Ive never had a problem with the diff, so i'm not going to worry about it too much. If it goes it goes, it will get replaced if and when it breaks!

DaHomie · #9 16-08-2011

There might be another reason for wobbling of the center outdrives as well. You might be wearing the outdrive bearings out prematurely because of a slight bend in the rear center drive shaft, maybe from hitting the battery brace during a chassis flex situation.
Happened to me a few weeks ago.

coleman758 · #10 16-08-2011

I'm referring to the diff output, (Were the drive shaft/axle goes in to the diff)
not the center. I checked all the bearings after one failed in the hub.

So there all ok. the center ones are all rock steady.

M

captainlip · #11 16-08-2011

I have a bit of wobble in the rear but it's probably due to wear on the cases

mark christopher · #12 16-08-2011

Quote:

Originally Posted by captainlip

I have a bit of wobble in the rear but it's probably due to wear on the cases

your fellow club racers told me it was too many pies....

captainlip · #13 16-08-2011

Quote:

Originally Posted by mark christopher

your fellow club racers told me it was too many pies....

You must be talking about dave!

WHITTLER555 · #14 16-08-2011

The outdrives to the driveshafts do wobble a bit because they are running through a rubber seal, no problem with that.

However if the center outdrives are wobbling I would check the two bearings on the propeller shaft/gear, if these feel anything like rough change them immediately as they will eventually wear so much they will damage the main ring gear.

captainlip · #15 16-08-2011

For me the fronts perfect and not shown any signs of wear, rears though have slight wobble and pin has worn the input shaft and mid drive shaft considerably, but again front is perfect :-/

coleman758 · #16 16-08-2011

Quote:

Originally Posted by WHITTLER555

The outdrives to the driveshafts do wobble a bit because they are running through a rubber seal, no problem with that.

However if the center outdrives are wobbling I would check the two bearings on the propeller shaft/gear, if these feel anything like rough change them immediately as they will eventually wear so much they will damage the main ring gear.

That would explain the movement...

The center shaft on mine is rock solid. No sideways movement at all.
I have also done a little mod on my diff case:

I have changed the two screws that clamp around the center input bearings to longer screws, I've put m3 nuts on the top. So there is no risk of stripping the gear casing. So the bearings are always trapped in nice and tight.

Nigel · #17 23-08-2011

i found my problem. the sink screw holding on the outdrive shaft was loose (forgot to thread lock it)

i also sanded off a bit off the bottum of the input shaft so I could really clamp it down around the bearings and the diff box to make sure it would not wobble at all.

the front is now perfect with no wobble at all. but no matter how hard i try to clamp down the rear it will still wobble up and down a tiny bit. not side to side just up and down.

do i have to worry about this?

thanks.

Nigel · #18 24-08-2011

anyone?

paulc · #19 25-08-2011

You don't need to do any modifing of parts like i said earlyer in this thread i've been running mine for about a year and a half without a problem so i would'nt worry about it just race it

RC John · #20 25-08-2011

Quote:

Originally Posted by 1slash

i found my problem. the sink screw holding on the outdrive shaft was loose (forgot to thread lock it)

i also sanded off a bit off the bottum of the input shaft so I could really clamp it down around the bearings and the diff box to make sure it would not wobble at all.

the front is now perfect with no wobble at all. but no matter how hard i try to clamp down the rear it will still wobble up and down a tiny bit. not side to side just up and down.

do i have to worry about this?

thanks.

I thought you were talking about the outdrives wobbling at the start of this thread, but I see from your pic, it's the input shaft.
I also had this problem. I originally fixed it by adding tape under the bearings to help the diff case squeeze the bearings tighter. That worked, but I later found the reason for the wobble was because the shaft (item 1 on your drawing) was a bit too long, and so I couldn't get the assembly squeezed tight before tightening the set screw. I shortening the shaft a bit and also lengthened the flat spot. This allowed me to clamp the bearings down solid before i tighten the setscrew. No more play since I did this, and no more tape needed.