[SamUK]

Stood there with a coffee a few minutes back thinking and twiddling the nut on the rear diff pinion, suddenly realised there’s far to much end float/free play going on in there!
Does anybody have althe FSM Page or clearances/tolerances for the rear diff to hand? I’m assuming it’s the pinion bearing that wants replacing, I don’t know for sure, never had one of these diffs apart.

Any tips, hints or advice before starting this job?

 

[SamUK]

Here’s a video, I’m sure you’ll all agree, that’s a lot of play!!

 

[shadetree]

yep, your pinion bearing is bad.

 

[shadetree]

just so you know ?, the pinion gear should not have any play at all !. and..it is made pretty much like all rear pinion gears and bearings in all the early model atvs. the only difference between the old style and the new pinion gears ?, is the new style are straight, where is the old style gears are curved, that's it.

 

[SamUK]

Thanks shady, I knew you’d post, this thread was screaming your name haha..
Is this a pretty straight forward job to replace the bearingbor is it a complete strip down of the rear diff? Is it possible to change the bearing as you see the diff in the video?
I have no idea what is involved.

 

[SamUK]

Are the bearings still available in the USA, can’t source them over here! Also, it would benefit a new spring between the pinion and shaft, are they available?
Is this a partzilla job?

 

[shadetree]

Are the bearings still available in the USA, can’t source them over here! Also, it would benefit a new spring between the pinion and shaft, are they available?
Is this a partzilla job?

don't know if the pinion bearing can be had ?, have not looked, but its easy to replace, if ya have the correct tool ?, and you don't have to replace the pinion needle bearing ?, you will need a pinion gear oil seal, as you can't remove the seal without destroying it. if the pinion needle bearing is bad ?, that will be a pain to replace..lol. and you wont know this , until you either pull the pinion gear ?, or tear the whole differential down.

 

[shadetree]

pinion needle bearing is around, main pinion gear bearing is discontinued, just checked . other than from Honda ?, you will need to cross reff the main pinion gear bearing, discontinued.

 

[shadetree]

here ya go, same bearing fits the atc250 big red --->https://www.ebay.com/itm/HONDA-ATC2...m3cc95d9ef0:m:mwya9L6Qh7v9YnLgVwe5org&vxp=mtr . kinda pricey , but its discontinued..always like this on ebay, norm sells for 60 something bucks.

 

[retro]

Attached is a PDF file taken from the 350 FSM. Rear diff service begins part way down the first page. I think you'll need a square socket (make one from square tubing?) to get the pinion lock nuts loose. @shadetree can probably tell you what size that nut is...?

EDIT:
This is the Partzilla link to the discontinued one... BEARING, RADIAL BALL (22X56X16)

 

[SamUK]

Thanks guys, very helpful as always

 

[shadetree]

pinion nut is 22mm, to remove the locknut, you need a 1 1/2 x 1 1/2 square tubing to remove it.

 

[retro]

pinion nut is 22mm, to remove the locknut, you need a 1 1/2 x 1 1/2 square tubing to remove it.

Thanks shadetree! I knew you knew the square tubing size, now I do too!

 

[SamUK]

Awesome.. Top man Shady, thanks.

 

[shadetree]

Awesome.. Top man Shady, thanks.

yw...glad I could help .

 

[shadetree]

pinion nut is 22mm, to remove the locknut, you need a 1 1/2 x 1 1/2 square tubing to remove it.

Thanks shadetree! I knew you knew the square tubing size, now I do too!

yep, I use that tubing a lot..lol. IT WILL NOT WORK ON THE TRX500'S THOUGH !, they have a larger lock nut, I believe it is 60mm for the trx500 rear differential pinion lock nut ?.

 

[LBZ_Duramax]

Sam, just buy a rear diff bearing kit and be done with it. It will come with all the bearing and seals/orings you need to complete the job. If I split it apart theres no way I would only replace one bearing out of 4. JMHO

 

[SamUK]

Sam, just buy a rear diff bearing kit and be done with it. It will come with all the bearing and seals/orings you need to complete the job. If I split it apart theres no way I would only replace one bearing out of 4. JMHO

Without doubt I will be changing all the bearings throughout the axle, just not sure if they were all available still.

 

[fishfiles]

I am sorry I didn't read this thread before as I am not a 350D guru as the header was calling out for , I do know the ring , pinion , bearings and seals and procedure for repair are all exactly the same as your wife's TRX250A , bearings and seals are still available thru OEM , Partzilla is one place to look , after market bearing /seal kits are available for that read diff , but I would not buy them any more , they don't last , AllBalls , Moose and all the cheap line parts are just that cheap , 1/2 the price equals 1/2 ( or worse) the time they last

 

[fishfiles]

it is not hard , some problems you need to hope you don't get into , is the axle splines being frozen to the brake drum and /or the ring gear , or the ring and pinion damaged as there is no after market for that yet , removing and installing the side bearings are no problems, it is the smaller tail end pinion bearing that can be hard to get out , there is a spring clip which can hard to remove , then you need to get the bearing race out , I having been wanting a small hole bearing puller , I have been welding a bolt to the race and pulling it out with a slide hammer