? Hot Racing Alum Tranny/Steel Gears - Tight, Rough, Crunchy - anything but Smooth

[Pushjerk]

Sup RCC. I still consider myself a newb, so I'll hand this off to the community.

Had a few bucks to burn, so for RPP's Halloween Sale I decided I'd like to upgrade the Transmission on my Bomber.

Picked up a Hot Racing Alum Transmission case and Transfer case, as well as the respective HR Steel Gear sets.

Now I haven't had much experience with hot racing - have always kinda thought they were crap, based solely on watching a Buddy's paper thin HR AR60 Alum Diff cover get demolished on a trail.

I have read, however, good things about their hardened steel gears, and T-Cases - after all, the highly regarded SS Bomb Proof Trans runs their cases. So.

Threw the Transmission Case together with steel gears with not much issue. Once test fitted, no screws, turning the gears sucked. Was Smooth only about 80% of the rotation. There was a tight/rough/crunchy spot on nearly every turn.

Once Screwed together, same symptoms.

Flipped the gears one by one. Shimmed and unshimmed shafts. All sucky.

One at a time, replaced the HR Steel gears with stock Metal sintered gears, and discovered the larger 28T gear is the culprit, as with the stock 28T in there, was buttery smooth.

One additional step I took was to see how it (the HR Steel Gear) rotated with the shaft, if it rotated true. I stuck shaft and gear in a power drill, and spun it up fast. upon visual inspection, the shaft and gear spun quite true.

I went ahead and built it up and the Bomber is running. there is a noticeable nudge (audible, very slight vibration) on every turn. At very low speed (super slow crawl, you can tell something's up in there). At higher throttle, the truck just doesn't care.

I've built a few kits to date, and have broken in a couple trannies, but never had this glaring issue.

Should I run it and hope it works itself out? Gears perhaps just have a tooth imperfection and will grind themselves smooth? Is this standard transmission break in?

Anyway, appreciate any replies from the community.

Peace.

-PJ

[Natedog]

Email/call the place you bought it from and get replacement gearset.

[Ninomaniac]

FWIW - I've had that happen with almost all bevely steely geary interfaces I've put together, but never with regular gears.

[Ditchrat]

There is a reason why we have the phrase break-in Period.
All gears require a break-in period. Most people don't bother. Not saying this is your only issue.

[mewalsh100]

You must have just gotten a bad unit that slipped through their QC. I have two of the HR Trans, one Wraith style and one AX/SCX style.(Each using LockedUpRC slipper eliminators) They both run silky smooth, all metal gears. I did pull them both apart before ever running them and used quality, waterproof grease. (Phil Wood bicycle bearing grease) When they're shipped, it looks like they just put a silicone diff fluid in them, which to my reckoning is just not "heavy" enough for the abuse a trans will see.

[Pushjerk]

Update for those invested. Ran the gears lightly out on the trail, and it was very disconcerting. The sound, the apparent vibrations. Continued use appeared to make it worse. Broke the tranny down and threw in the stock gears, went and ran it and everything was like butter - Love that HR aluminum transmission housing.

Got it touch with the folks at Hot Racing. Had super positive experience, and now have a new set of gears in hand.

[Mikeinsocal]

Glad you got it handled but I just thought I'd throw in my experience with HR gears... I put a set of their gears in a wraith trans and in the first half of the case they appeared good so I greased em up and after putting the other half of the case together I had a bad spot. After very close inspection I found tiny shavings between a couple teeth and after cleaning them out things were nice and smooth.

[Pushjerk]

Hey Mike, yeah man that was my initial thought - chips light. I cleaned it so very throughly, even brought out the magnifiers. nothing. Squeaky clean, and still they bound up every rotation. A bummer, but s'all good now. Now i just need to go digging through my Bomber to get to those tranny gears...sigh