Need Help With Helical Diff Gears
 

Hello,

today I picked up a helical pinion gear for my 1/8 buggy's front diff, and also had to pick up the diff gear to go with it.

When re-assembled the diff after changing out to hardened outdrives too, the diff gear and pinion will not sit correctly in the housing.

Hopefully these pictures will give a clearer understanding:

http://img827.imageshack.us/img827/9697/cimg0001dv.jpg

http://img268.imageshack.us/img268/3184/cimg0004wa.jpg

http://img811.imageshack.us/img811/4458/cimg0008z.jpg

http://img546.imageshack.us/img546/44/cimg0009y.jpg

http://img228.imageshack.us/img228/8547/cimg0012d.jpg

Hope fully you can see that the diff gear is not sitting on the pinion well, lifting it up at one side.

What is causing the problem? and how can I resolve it?

Thanks

The diff gear looks to be too thick, making the overall size of the diff bigger, so it's pushing the bearing out. Meaning it wont slot in the housing correctly.

Is it an aftermarket gear?

ben

No it's not mate, Got it today from LHS. Pinion was from caster website that LHS ordered in, and diff gear was taken from another buggy still in box at the shop.

It's just strange that the gear that comes from caster, doesn't fit the diff :thumbdown:

you said it was a "helical" pinion (it does seem to look a tad helical, but only a bit) but it looks like you're using a straight cut grown gear.
well those 2 aint ever gonna match up are they! :eh?:

you need a straight cut pinion gear too :)

The crown gear isn't straight cut mate :)

It's deffo helical, both are slightly curved, they mesh perfectly fine when out of the diff housing.

furry muff, it does look straight cut in those pics tho :)

haha, indeed it does :) they are only slightly curved, almost not worth having as they cant improve surface area that much...

does it have the same amount of teeth as the pinion you took out?
is it the same diameter?

were both parts for/out of the same kit as yours?

It does have the same number of teeth.

I have however solved the problem now (if you can call it that).

The gear I have is too BIG, It's frustrating because it is the ONLY 13t pinion gear caster list on their website. I have sent the caster support team an email notifying them about my problem and hopefully they should be able to point me int he right direction for the correct gear.

The most annoying this is, I had to buy a diff gear to fit the pinion, which cost £20, and it doesn't even fit!! GRR :P

then the shop sold u good not fit for purpose

I do agree ;) however, caster only list that ONE pinion on their site. Hopefully i can get this resolved in a few mins. Talking to a guy from caster now

Glad you're sorting it out, however annoying it gets!

This is a straight cut bevel gear. If it looks bent in an way, it won't work. The pinion in your photo looks a bit worn! As the pinion line is co-axial with the spur gear line, and the tooth is not noticeably curved, only a straight cut bevel will work. Helical (spiral) bevels are used to increase tooth area contact, and hypoid bevels are used to lower the line of the input shaft in relation to the output shaft.

This is helical (spiral) and further down the same page is hypoid bevel. As you can see, the spiral is very obvious. Both are very expensive to cut, and that's why the cheaper straight cut gears are used. HTH :)

Hope you get it sorted. Just being nosey, but when you say it's too big is it hitting the housing, or is the pinion bottoming out on the root of the spur gear?

Hey mate!

Thank you for the information, both gears ARE helical, though they may not look like it. The pictures obviously don't show it too good!! Sorry about that.

They do both have a very almost un-noticeable curve, though it is there. As stated above they mesh perfectly when out of the diff housing its just not fitting right in the housing.

The pinion is brand new, It hasn't had any power put through it, same as the bevel diff gear. got them both today.

It's too big, almost like the pinion needs to be off centred in the housing to accommodate for its diameter. It's not hitting the casing, when the diff it's self sits in the housing without the pinion installed, it's spins freely and there is no binding.

Thanks mate!!

Issue should hopefully be resolved, I am picking up a new crown gear tomorrow morning. Will report back tomorrow.