Thoughts on transmission rebuild/repair?

[Tk8398]

I have 3 RC10s (2 A stamp, one with an aftermarket chassis and A&L trailing arms) that I bought earlier this year, and I assembled and ran them a few times, and have managed to break all 3 transmissions after running them only a few times just by driving around in the dirt with a 17t brushed motor and NiMH battery. After looking at what it would take to repair them, it would be hundreds of dollars and months of ebay searching to fix the transmissions, rebuild the shocks (which all 3 of them need), etc. I paid less for them than what they usually seem to go for on ebay, and it wasn't money i expected to get back anyway so that's no big deal, but the people who bought out the stock of discontinued $2.50 parts to flip for $50 each on ebay kinda take the fun out of it for me.

I really just want a buggy that drives like an 80s-90s car to drive around in the dirt at my local park that doesn't require hunting ebay for overpriced parts to keep running, am I missing something or would it probably be a better idea to sell the RC10s and get a Kyosho Ultima or Tamiya Super Astute (or something similar) instead?

[GoMachV]

The rereleases would be a great way to go, such as the Kyosho ultima. The problem is, the RC10 was rereleased just a few years ago and here we are... so while you can get parts for them now it’s hard to say in a few years how that will pan out. AE barely supports its current line of cars, and has really shown the vintage community what they are made of. Kyosho doesn’t really have a rere track record to look at but people with their first rerelease, the Scorpion, can still get parts easily.

[Tk8398]

The Scorpion was only a year after the RC10 re-release, and yeah it looks like there are far more parts still available. I wouldn't buy a new AE car, it seems like the same situation that repeats over and over with a well known american company getting sold off and run into the ground making cheap junk. The fact that they could easily keep making the RC10 classic parts but have chosen not to when that car is literally the entire reason the company even exists seems absurd to me.

[GoMachV]

Plus the building of the ultima from a kit and running it around are just a blast. The kit goes together well and the trans runs like a Swiss watch with mostly metal gears, sealed diff and a slipper. Really the only bad experience is the stupid shock gaskets which once they are in place are fine, and the shocks don’t feel too bad (way better than originals). I’d highly recommend the Ultima as a fun runner with parts availability.

[juicedcoupe]

What did you damage that cost that much to fix? Many of the common "wear" parts are still easy enough to find. Proper care and setup of the differential and slippers will go a long way with the trans life.

Unless the shocks a physically damaged, the o-rings can be replaced. I bought these in bulk on Ebay.

[Tk8398]

I only took one of the transmissions apart, but to make a working car again with that one it would be approximately $180 assuming I don't need anything else.

Shock rebuild kit - $30
Spur gear - $15
Differential drive rings - $7
#6623 bushings - $45
#6628 spring - $15
#6626 diff balls - $18
#6633 outdrive seals - $35
#6926 screws - $7
Bearings - $10


One of the others is a 6 gear that probably needs the same, and the other is a stealth that something broke inside and it just makes a clicking sound and the car doesn't move. I know they are very old and it's reasonable to expect they will need a lot of work, but looking at the cost of new kits vs fixing these, and how much cheaper it would have been 5 years ago to buy most of those parts makes it seem like not that much fun. I have a couple of T4s also which are far less worn out and seem more durable, but aren't the easiest to get parts for either.

[juicedcoupe]

I suspect that if you look closer, you don't need nearly as much as you think.

You can usually replace the o rings in the shocks and be fine.

Kimbrough spur gears are ~$6.

The teflon bushings are typically fine. Sometimes, they get pushed into the diff tube.

Pan car drive rings can be used, and are cheap. Associated still sells them new as well, cheap.

Unless you crushed the diff spring, it is likely serviceable.

Regular 1/8" diff balls (pan car) work fine for general use.

Unless this is a resto, I'd do away with the felt seals and do the outdrive bearing mod. Only cost a few dollars and is a nice improvement.

No need to pay Associated prices for general hardware that can be purchased for half the cost.


The Stealth probably has a stripped diff and/or idle gear, both are available new. Diff rings and balls are still available as well. The other parts are still available as well but are a little more pricey.

[Tk8398]

The spring is gone (missing when I got the car), along with half the diff balls. The teflon bushings are definitely shot (one is worn down to about 1/4 the original thickness), and the bearings for the top shaft are very loose. I am not even sure what is wrong with it, because the car wouldn't move and sounded like the gears were stripped, but when I took it apart the gears still had all their teeth and don't look worn. I think they are actually Thorp 48 pitch gears from what someone told me who I showed a picture of them. The other 6 gear probably has the same issue, as it stripped the spur gear after running it a couple times, and the top shaft is really loose.

[juicedcoupe]

I "think" that the teflon bushings are just pieces of common 3X5mm teflon tubing, maybe 2X5mm with the center drilled. The re-re ones look like a different material.

Before I'd pay that much for the bushings, I'd buy a roll and try, especially if I needed multiple sets.

If you decide to rebuild and can't find a diff spring, send me a message. I'm 99% sure that I have an old one in my parts stash.

As I said about the diff balls, they are just 1/8" balls. I have a set of $2 RJ Speed ones in my six gear car right now.

[juicedcoupe]

Edit. Double post.

[Tk8398]

As far as the spur gear would this one fit? http://kimbroughracingproducts.com/store/index.php?dispatch=products.view&product_id=29832

Also, what is the best way to seperate the gear from the inner part of the slipper clutch hub? That bearing needs to be replaced, and I think is a big part of why it didn't work properly. There are actually several of the gears on ebay for cheap, but I don't know if I could find the other parts if I just wanted to replace the whole part rather than taking it apart.

[juicedcoupe]

It is just a tight press fit.

I want to say that I just found something to fit around the gear, then hit the tube a couple times with the butt of a screwdriver.

[Tk8398]

I finally took the sealth transmission apart, and there is nothing broken, but the car didn't move at all when I last tried it. I don't really understand how to locate the issues, I thought that the gears would be broken, but neither of the ones I took apart (stealth and Thorp 6 gear) have anything visible wrong but the cars still would not move.

[mikea96]

Was the diff slipping in the stealth transmission?

[juicedcoupe]

Are your diffs loose?

On the Stealth, the slipper and diff?