Diff Rebuilding 101

[SlingItX]

I've rebuilt several diffs at this point in my r/c career, but I have yet to see a really good article or post on the best method for effectively shimming the gears so they mesh perfectly. I wouldn't even know what 'perfect' looks like if it slapped me in the face.

Seriously, all the diffs I've gone through and rebuilt last anywhere from a half to a full gallon (rare). Is this good, bad, average... ? Am I doing something right? I've only ever shimmed per the manufacturers instruction so I really don't know how to shim to really mesh the gears perfectly. Can anyone tell me the best way to identify a properly meshed diff? It's not like I can measure lash. I just put them together, throw in the recommended shims and check for excess slop, if it's really bad I throw in some more shims to snug it up.

Have I answered my own question? Just get it so it's not too tight (short of binding) and not too loose? Is that the big secret? Oops, one more thing, do you actually have to break-in a diff? I heard this before, but not frequently enough to make me want to do it.

Thank you in advance for your input.

-SlingItX

 

[HumboldtBlazer]

Originally posted by SlingItX
I've rebuilt several diffs at this point in my r/c career, but I have yet to see a really good article or post on the best method for effectively shimming the gears so they mesh perfectly. I wouldn't even know what 'perfect' looks like if it slapped me in the face.

Seriously, all the diffs I've gone through and rebuilt last anywhere from a half to a full gallon (rare). Is this good, bad, average... ? Am I doing something right? I've only ever shimmed per the manufacturers instruction so I really don't know how to shim to really mesh the gears perfectly. Can anyone tell me the best way to identify a properly meshed diff? It's not like I can measure lash. I just put them together, throw in the recommended shims and check for excess slop, if it's really bad I throw in some more shims to snug it up.

Have I answered my own question? Just get it so it's not too tight (short of binding) and not too loose? Is that the big secret? Oops, one more thing, do you actually have to break-in a diff? I heard this before, but not frequently enough to make me want to do it.

Thank you in advance for your input.

-SlingItX

I was getting about a gallon-to a gallon and a half on Storm diffs, and don't have a good idea on my MBX5 yet. Sometimes I would rebuild the diff just to do it if I had a race or wanted to check the fluid as some always leaks escapes out. Diff rebuilding is just a fundemental if you race off-road imo.

 

[SlingItX]

HB-

I don't mind doing it at all, but I just haven't found the best way to do it, except by feel (a little subjective).

So, am I on to something - shim until it's snug, but not binding? My point is, I just rebuilt a set and one of them was particularly loose at recommended number of shims. So I threw in another set of shims to adjust and it was almost too tight. I assume snug is better than loose... maybe? As a result the buggy will roll (being pushed by hand), but not as freely as my other buggy. I guess I'm just going to have to keep experimenting.

Thank you.

-SlingItX

 

[HumboldtBlazer]

Sounds like you got it. I just make sure they are shimmed enough as so the gears can't "rattle around" and come out of place. snug but not tight if that makes sense is how I like mine, or what works for me I guess.

 

[SlingItX]

Many thanks, sir.:thumbsup:

 

[Çh®i§tiªñ]

Snug is good. Too tight, and when they heat up, they might begin to flake from the friction. That 'flake' (metal shavings) will eventually eat through your gears in there like a dog on peanutbutter.

 

[SlingItX]

Never thought about that. Could I lock the center diff with peanut butter? :classic:

Maybe El Pirata could use this instead of 100k? Hmmm... I wonder how chunky would hold up.

Nice analogy Christian, lol.

-SlingItX

 

[Çh®i§tiªñ]

lol - thought you would enjoy it