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JRX2 Differential

Posted: Wed Dec 15, 2010 8:53 pm
by RCveteran
Most of this has been covered but some more lowsy pics for the record. I was going through all my diffs in hopes of having one with the bearing center gear and do not. Sadly because I do have the special thinner bearings, which you can see measure .108" thick vs a standard bearing of .123" (probably .125, my caliper is not great).

Also shown is a thorp diff gear next to a stock one. It is aluminum and has the round holes compared to stock diff gear which are square holes. So I need to find a ball bearing diff gear as I want to run brushless on this puppy and I think it will hold up better.

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Re: JRX2 Differential

Posted: Wed Dec 15, 2010 11:13 pm
by GJW
yeah i have been running the ball raced diff gear in my pro with a 9 turn brushless without any problem's, the thing wheel stands with ease! big fan of the LRM gearbox having the diff up high as the dirt just does'nt get in there. got a spare to slot straight in just in case also with the bearing gear 8)


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Re: JRX2 Differential

Posted: Thu Dec 16, 2010 1:19 am
by JK Racing
not that I have one (just went through my stash), but you are looking for:

A-3021 Ball bearing diff gear

Re: JRX2 Differential

Posted: Thu Dec 16, 2010 8:30 am
by RCveteran
Lucky me, I had one LRM transmission yet to be taken apart attached to an old very ratty and early x2 from ebay a while back I just pulled apart, and look what I found!

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Oddly this one had two .125" thick bearings in it and not the thinner .108" losi special bearings. Whether it was working I do not know, I am going to reubild with the thinner ones and ceramic balls.

Thank you.

Re: JRX2 Differential

Posted: Thu Dec 16, 2010 8:55 am
by RCveteran
Wait one second, this one is metal. As are the diff side gears, a Thorp instead I believe. The idler gear is a white plastic in this trans as well.

So are two .125 bearings correct for this Thorp gear?

Re: JRX2 Differential

Posted: Thu Dec 16, 2010 9:59 am
by JK Racing
from what I have read in the past, yes, thorp used the 2 thicker bearings.

Re: JRX2 Differential

Posted: Thu Dec 16, 2010 3:34 pm
by RCveteran
Makes sense as the hole in the female half of the diff is deeper on the Thorpe looking at it. Anyone run the stock metal idler gear with Thorpe metal diff gear. I am thinking a little grease would be good for metal to metal gear?

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 4:24 am
by slow_jun
Excus me for my ignorance,but will the Throp allu diff gear stand up with the abuse of a BL power plant?as opposed to a ball center diff? I
And lastly, is this (center ballrace diff) still available (where and how$$$) or will only be ailable stashed away and prices will be so high as the sky? ;-)

What is an alternative for a stock jrx2 tranny? Im not too familiar with the retro fit tranny(just browsed vintagelosi) ,and not sure if this will fit a standard x2 tranny mountng holes or mod will
Be done to accomodate?

Thanks.

Jun.

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 7:54 am
by RCveteran
There are two thorp center gears, one with two bearings and one that uses a single bearing like the original losi diff.

I would think either would hold up. Some report using a standard Losi one bearing fine with brushless, others not. The ball bearing gear from Losi is no longer available. Nice folks here helped me out though, there may be more out there.

The retrofit tranny fits the older chassis and is basically a XX transmission internally from what I understand, XX parts are usually pretty cheap to find.

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 10:56 am
by slow_jun
Thanks mate, so where can i get these parts from xx?parts list would be appreciated,
Sorry,been awhile since i ve been back to losi, still learning again,
anyone has spares forthe two bearing gears or xx retro fit tranny, welcome your help guys.

Thanks,

Jun.

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 11:44 am
by RCveteran

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 6:26 pm
by GJW
part number's for the bearing diff gear are as follow's :)

a-6904 thin bearing's
a-3021 diff gear only
a-3020 complete kit

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 8:02 pm
by slow_jun
Thanks for the Links,

are there still available? and where could i get them.

is the tranny case totally different from the original JrX2 casing?

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sorry for questions as i dont have yet the truck with so i still have no basis for the comparison.

I will try to look for these if its still available.

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 8:10 pm
by bearrickster
no the cases are completely different. as are all of the parts. no their not available any more you have to find them and their not cheep.

Re: JRX2 Differential

Posted: Mon Dec 27, 2010 8:58 pm
by JK Racing
the motor plates are the same :)

jun, let me look around, I may have most if not all the parts to build one...minus the bearings, which are common bearings for the newer losi cars.