Homebrew Stealth Diff Locker

[RAM2500]

I have a couple of older Stealth transmissions (B2 model?) that I wanted to lock and I know that 62PYRO makes a killer spool, but it's too big for the older Stealths. I used an older Stealth in my first build and I locked the stock outdrive cups with JB Weld and modified my drive shaft ends (stub shaft) to fit the outdrive cup. It's held up fine so far for almost a year, but it was not a very clean installation. I decided to try see if I could get a stampede transmission output shaft to work in a Stealth. Don't know if anyone has tried this before but here's how it went.


Here's an original transmission...


Here's the parts bag...


Before trying to make any modifications to the outdrive cups or stanpede output shafts, I would recommend heating them up with a propane torch to get rid of the heat treating. I don't know the science behind it, but I heated each part for a few minutes each and it made it much easier to cut or drill them. The first modification was to get rid of he teeth on the output shaft. I chucked it up in a drill and ground down the teeth on a file. Just take the shaft diameter down so that it just slips into the stealth outdrive cup. The next thing I did was tap the end of the pede output shaft with a 4-40 tap. You might be able to get a 3mm to work as well, but the 4-40 worked great for me.





The next step is to cut off the ends of the outdrive cups. Cut them so that they just clear the outside face of the transmission (about 1/16" past the slot in the cup). Next I ground some slots for pins in the outer edge of the outdrive cups where they snug up against the diff gear. Align them with the ball bearing holes in the diff gear. You could probably get away with one pin but I used two just for added strength. These pins will lock the diff. You will also need to drill out the center of one of the outdrive cups (the one with shaft to center it in the diff bearing) with a 7/64" bit so that the all thread will slip through to secure the output shafts together. Cut a small piece of allthread or 4-40 screw and tighten the two output shafts snugly to the diff gear. Next I drilled both outdrive cups through the output shafts with the same bit and pinned them (That was the sequence I originally used to build it. I took it apart for photo clarification). You can use the pins that come with the output shaft set and cut them down to 1/4" or so. Line up the holes in the diff gear with the slots in the outdrive cups and pin those as well. If you cut diff lock pins too long, they will bind against the transmission case so be a little careful there. I has to disassemble once and grind one down a little.

Here are the pics...

[RAM2500]

Here are the finished installation photos. The clearance for a 91 tooth spur is really tight, but it worked. I haven't run it yet, but I cranked on the shafts pretty hard and they are holding. I'm going to drop it in a K2 chassis shortly and I'll keep you all posted!

[JeremyH]

Looks good!

[RAM2500]

Thanks! Not the highest quality machine work since it was all done with hand tools, but it's really tight and still serviceable. Probably not worth the effort on a B3 or B4 since 62PYRO's spool is such a great piece of work but it's a pretty innexpensive fix and worth it if you have an older model that you need to lock. At least until he comes out with a spool for that one.

[Cloak]

Great job on that. I think I have an older one lying around that I just might have to try something similar to.

I can't wait to get some access to my tools again.

[RAM2500]

Originally Posted by Cloak

I can't wait to get some access to my tools again.

Moving is such a pain!

[HndsWthtShdws]

Originally Posted by RAM2500

Before trying to make any modifications to the outdrive cups or stanpede output shafts, I would recommend heating them up with a propane torch to get rid of the heat treating. I don't know the science behind it, but I heated each part for a few minutes each and it made it much easier to cut or drill them.

The process is called annealing. What you want to do is heat the metal to a high temperature and let it cool slowly. This will make the metal softer and easier to work with.

If you ever break a tap you can drill it out if you anneal it first.

[62PYRO]

Just for the record,the b2 one is the same as a b3/t3.But since I don't have many(1) left,this is a great mod.Saved money and works,Who could ask for better?
Pat

[chevy42083]

Originally Posted by 62PYRO

Just for the record,the b2 one is the same as a b3/t3.But since I don't have many(1) left,this is a great mod.Saved money and works,Who could ask for better?
Pat

Although, that doesn't look like my b2 tranny. I bought the b2/b3 locker from 62PYRO, and it fit perfect... that must be an older tranny in the first post.

Good mod though.

[62PYRO]

Originally Posted by chevy42083

Although, that doesn't look like my b2 tranny. I bought the b2/b3 locker from 62PYRO, and it fit perfect... that must be an older tranny in the first post.

Good mod though.

You are correct sir.By the pics,that is a first gen Stealth.Easiest mounting holes out of all of them.Great call.
Pat

[RAM2500]

Originally Posted by 62PYRO

Just for the record,the b2 one is the same as a b3/t3.But since I don't have many(1) left,this is a great mod.Saved money and works,Who could ask for better?
Pat

Pat,
Is the one I modified actually a B2? I didn't know they were the same size as a B3. I am not that up on my Stealth history. I just happened to have an old one that I used in my first crawler because I was too cheap to buy a pede but it worked out great. Either way, it's good to know you make the smaller ones to. Honestly, like almost all custom parts, it you take into account the time it takes to get it right, the parts you guys sell are a bargain! I'm just one of those people who likes the challenge once in awhile. Kept me out of my wife's hair for a couple days anyway!:-P

[RAM2500]

Originally Posted by chevy42083

Although, that doesn't look like my b2 tranny. I bought the b2/b3 locker from 62PYRO, and it fit perfect... that must be an older tranny in the first post.

Good mod though.

There's my answer. I just typed my question too slow.

[RAM2500]

Originally Posted by HndsWthtShdws

The process is called annealing. What you want to do is heat the metal to a high temperature and let it cool slowly. This will make the metal softer and easier to work with.

If you ever break a tap you can drill it out if you anneal it first.

Hmmmm...how'd you know I had a couple broken taps to get out? Not too up on my tapping skills either. I broke a couple on my first build.... I'm getting there though.

[RAM2500]

Originally Posted by chevy42083

Although, that doesn't look like my b2 tranny. I bought the b2/b3 locker from 62PYRO, and it fit perfect... that must be an older tranny in the first post.

Good mod though.

Originally Posted by 62PYRO

You are correct sir.By the pics,that is a first gen Stealth.Easiest mounting holes out of all of them.Great call.
Pat

I never really paid attention to it, but I do have a B3 that I picked up used and I'm pretty sure it has one of your lockers in it. I compared that diff gear to the one I modified and it is a little larger which is the reason I ended up doing this mod. By the way, the locker on my B3 is awesome. Fits perfect!

[STANG KILLA SS]

heres how i did my gen 1 stealth
HOW TO: Gen 1 Stealth Tranny modded for Crawler Use.

[RAM2500]

^^^^^^ That's pretty similar to how I did my first one with Revo shafts except I just tapped the stub shaft pin holes with a 4-40 and ran a screw through the slot in the outdrive cup. JB'd the diff and it's held up for almost a year now. I jsut wanted something a little cleaner and more serviceable for my next build. I really like the reliability of the Stealths.

[Natedog]

Great idea man.

Originally Posted by RAM2500

....Not the highest quality machine work since it was all done with hand tools, but it's really tight and still serviceable. Probably not worth the effort on a B3 or B4 since 62PYRO's spool is such a great piece of work but it's a pretty inexpensive fix and worth it if you have an older model that you need to lock. At least until he comes out with a spool for that one.

Yep, 62PYRO's spool is a good deal as are many other vendor's parts especially when you look at how long it takes to make these kinda parts with hand tools in the garage.

[RAM2500]

Originally Posted by Natedog

Great idea man.

Thanks man. Smooth as glass so far!