Hybrid Diff Instructions for Review
 

Please find some instructions for review / comment.

Shaun - Thanks for use of the pics

Cheers

Having never used these how much is required (if any) in reference to shimming?

Other than that it's a really nice write up. Simple and clean with good pictures, sentences short and to the point. I like it!

I've neve built one of these either, but I've done stockers.

1) I have no idea how to shim a diff, or what parts to buy to do this shimming. Some instructions on this would be nice.
2) "Assemble the differential according to the manufacturer’s instructions." Ummm....in this case, RCM is the manufacture isn't it? If a customer has a problem, they should and would call RCM first. So the instructions should be included with the diffs.
3) You reference some parts in your instructions by their street name. But in the diagrams and pictures they have part numbers, but no names. You should be consistent with this. Example - "flange bearings" must be the C8020's in the diagram?

Just some thoughts so far....

See comments below:

Thanks for feedback - v0.2

I for one am glad you wrote this up. Came back from bashing this afternoon with what I believe to be a blown rear diff. TIme to upgrade I guess (but that's a tough 250 bucks to swallow).
Has anyone ever blown a front diff? It seems to me that the rear takes most of the load and abuse. And at the cost of this, it would be nice, I think, to just be able to replace the rear.

I do have a aluminum cup already (golden horizons brand?), maybe I'll just try that for now and see how that holds up.

You have to do both, as the ratio is different to the traxxas diffs..

Try the al cup and shim the stock diff properly. A good diff shimming write up would be good. I will have to take pics next time I do one. I did find a good writeup once for a tmaxx diff, can't remember where.

I have my old diffs that I removed - Front and rear both with aluminum inner and outer cups if you are interested...

In the diff selection section, I think in the table you should have "Top Speed with stock pinion" or something to that effect. I think it could be a little confusing to some people.

I'm also not a huge fan of the layout and how you reference the pictures... but I also proof read mathematics journal articles half my waking hours, so I'm trying not to be too pedantic. It did take me a second to figure out that table though.

I'm just trying to nitpick though, to give feedback. I think it would be fine released how it is, and I've seen worse written manuals released with products.

The info mentions that the HB diffs use hardened spiral cut gears. The truggy are spiral, but the buggy are not spiral cut. Unless HB has changed them recently.

The D8 uses the spiral cut diff gears. At least the hot bodies site lead me to believe such a thing. I bought a Lightning buggy just before release of the D8 and it has straight cut.

Ok, I have the buggy and truggy gears, and only the truggy are spiral cut. From what Sikeston found the spiral cut tends to place addl thrust on the inner pinion bearing, potentially causing failure. I would generally stick to the buggy gearing.

On a side note, the lst diffs incorporate a spacer between the inner and outer pinion bearings. This is handy for multiple reasons, as you can assmeble the bearings,spacer and the drivecup on the pinion and then just drop it into the diff case. Plus the spacer will spead any thrust load across both of the bearings, which should help the races survive.

I am not that good with electronics theory, but I can sure see mechanical failures before they happen. No real need to mess with the truggy gears.

I am not wild about the teflon shims as stated in that link. I tried this and had wobble that was unacceptable so I stick with metal shims. Any size shim rings you need can easily be found at www.McMaster.com. I got the original instructions I used for shimming diffs years ago from someone on the TRX forums. It also had notes about shimming the pinion gear which helps a lot as well. Sometimes there is a lot of front/back play in the pinion gear against the ring.

Here's the instructions for assembling and shimming the diffs from UE. I used them for my 6 and 8 spider diffs:

8 spiders:
http://www.unlimitedengineering.com/...nsV1.1-Web.pdf

6 spiders:
http://www.unlimitedengineering.com/...ctions-WEB.pdf

WOW what a great thread..:gasp: Extremely well written,:yes: it should help out many of the newcomers for many years to come..

Great Job Sir..:party: