overdrive question
 

So just finished putting the traxxas 1-tooth larger pinion in the front axle. Seems to help a bit"thumbsup". The way the driveshaft connects is different tho, was wondering if there is a pin-grub screw ( like a wheely king only smaller) that I could use to go thru the hole, or do I just have to keep an eye on the little grub and hope that it holds the shaft on?:roll:

I ground a flat on my pinion. If I remember right you should grind back just a touch farther anyway to get the set screw to go back far enough.

all i did was install a second grub screw on my mip shafts and put plenty of locktite on both of them and have yet to have a problem. (knock on wood) iam going on my 3rd comp and countless practice sessions.

X2 grub screw on each side of the mip's with loctite...no grinding & no problems so far.

Yup, locktight and two grubs. I was thinking about drilling and tapping the hole on the pinion to the same size as the mip grub screw holes and then using a grub screw that would go all the way thru. But I havent need to.

Thanks guys. I imagine the little grub will hold, but when I have time I might drill & thread one all the way thru, then no worries for sure!;-)

My MIP D-shaft just backed off w/ my overdrive pinion. I am going to add a second grub screw and it should be fine.

OK, a search didn't yield a great thread to add to, soooo.......for those that did the standard overdrive mod, how did you shim the new pinion to the existing "spur" gear?
The stock shim is ~0.007", it felt like it needed a ~0.02" shim.
Things felt fine, UNTIL I assembled the front axle (including the C-hubs), then it appears that I need a thinner shim.
While it felt fine with the shim & axle, when I went to assemble the full axle (including HR C-hubs) the left front (looking from the back) axle stub is too tight. I am assuming the pinion is too far forward and driving the axle stub shaft out leading to a very tight C-hub/knuckle pivot angle.

Thoughts???

What, if any, shims are you guys running with this mod??

No shims here Charlie. When I put mine together it was tight and I just ran it to break it in. No issues so far."thumbsup"

x2 :mrgreen:

Wow, same replies I received on my home crawler site....thanks....."thumbsup":lmao::lmao:

I didn't know if it was me, or that others had the same issue. My search didn't yield something, thus I wanted to know as well as help the next guy.

Thanks Jay & Bob.8)"thumbsup""thumbsup"

I'm assuming (hope to not be proven wrong) that you just used the "stock" shim that was on the front diff pinion gear?

Now, back to taking it all apart, again.

I have done this to 3 different axles one I had to shim I think there are some variances between the housings gears and bearings.;-)

Thanks guys, it's back together with the stock shim.
The thicker shim I had made the gear mesh feel great, but I'm guessing it pushed the diff towards the "drivers side" of the front axle creating issues getting the knuckle on since the axle stuck out.:roll:
The gear mesh feels a little loose now, so we'll see.8)

I have now tried the over drive in two of my MRC Pro's and have had a binding in the front axle. It happens when I change direction from reverse to forward, it catches real hard and the rear pushes it through. Does this mean I need to shim my pinion? I pulled the traxxus gear out of my son's and my car but would like to figure this out.

Sounds like you are pushing the pinion gear in when you attach the drive shaft. This will cause binding and there is no shim to help the gear from being pushed in.

You need to grab the output shaft and pull it out as far as it will go, then loosen the grub on your drive shaft so its not sticking out into the hole, slowly slide the drive shaft over the output shaft and slowly tighten the screw. Watch the shaft to make sure it doesn't get pushed in when sliding the drive shaft on.

The overdrive is beneficial in some cases, but not worth the hassle/cost in my opinion. I am sure many local and national comps have been won without it.

Thanks Slaughter, I should have seen that.

I suggest checking the ring gear,often there is a little wear from the og pinion.I use a triagled file to clean the teeth,also doesnt hurt to hit new pinion/ring gears either.Also the more you drive,the better it will get.

take the pinion shaft and chuck it into a drill,I break em in like that,but not wide open,mid speed.be sure you have plenty of grease in there if you do this though.

Not recently.

The only situation where front overdrive is a hinderance is when driving backward. For me, this modification consisted of nothing more than installing the traxxas pinion. No shimming, nothing special needed. It was about as simple as it gets. I will never reinstall the stock pinion in the front axle.