XXX-NT diff gear wobble

[Chad]

I rebuilt my XXX-NT transmission with Niftech pinned outdrives, niftech diff rings, balls, bearings, and micro-fine diff set screw. I also used Robinson's aluminum differential gear, Losi aluminum top shaft and Penguin RC carbon fiber brake disc. I ran the diff in on a stand with niftech lube and break in tool. As I spun the the outdrives the diff gear started to wobble left to right slightly. I say slightly, but I feel it may have too much slack. How much left to right play should the diff gear have between the outdrives? Many people have said this is normal but with a new O.S. .18 CV-RX I can't take any chances. I am afraid the niftech outdrives are not machined enough where they come together and meet at the little diff gear bearings! Can someone tell me if this wobble is normal? Thanks Chad

 

[hpiracer]

hello chad you put this thread in the wrong section it should be placed in the stadium truck section i pm'ed a mod to correct this for you

 

[JESSE G]

Hello Chad welcome to RCNT if you go down to the bottom of the page you will see the Forum Jump click on that and you can find the best place to post your thread you will have a better chance of getting help that way. Anyway nice to have you as a new member glad to have ya

 

[Rolex]

Side to side wobble is not unusual. My stock gear had the same thing, and never caused a problem. When it was changed to a different ratio, the new one was fine. Some just seem to have a slight warp to them.

 

[Chad]

I would like a little more input about my XXX-NT DIFFERENTIAL GEAR wobble. I only got one real explanation for why there is so much slack between the two outdrives. The rest of the feedback was about how I put my post in the wrong section of RCNT. Sorry, I'm kinda new to this internet Q/A. How do I repost or can I even do that? Thanks for the help so far. Chad

 

[olds97_lss]

It's already been moved to the section for stadium trucks.

I had the RRP gear as well, but I just used losi carbide balls, hammund ghuman diff nut and the thrust bearing that was in an actual race instead of balls floating around.

I noticed mine had a mild wobble to it as well, but after 6 gallons of abuse with an OS 15 cv-r(x) it still looked like new and still spun nice and smooth. Those losi carbide balls really helped things last. Before I got those, I was rebuilding the diff about every gallon due to worn ring washers if not a stripped monster gear.

 

[Chad]

The slack between the two outdrives is excessive. How do I fix this? I would just shim the diff gear between the outdrives, but I can't do this because of the pinned outdrives and matching diff rings. My shims would have to have a notch dremeled into them. This could be a very tedious modification, what do you think? You, Olds 97 seem to have the best advice out of everyone. Thanks Chad, Oh by the way! I am a fanatic for precision tolerances.

 

[olds97_lss]

What do you mean by excessive? More than a mm or two?

You could shim from the outdrive to the bearing in the diff case... I never shimmed anything when I had the xxx-nt. I was to new to know better. When things got sloppy, I just replaced stuff. Like bearings and the diff case itself. That would normally take out any excess slop.

BTW, I used boca green sealed bearings. They were nice and tight. They also lasted quite a while.