Topcat / Cougar Differential Differences?

[RCveteran]

Did the diff rings and outdrives change to hex drive set up on the Cougar? My melted topcat diff in pic 1. Pic 2 is part of a parts lot I just got with a mixture of stuff. The center pulley has same part # T203 and then and an X which is not on Topcat one (just the X missing) or at least not legible on mine.

Looking at this it is a direct fit but don't have a Cougar yet to compare it to.

[kaszal]

If it's any help, here are some tips on restoring your old diff...

You can soak the parts in brake cleaner, which is cheap too. Give 'em a good scrub with a toothbrush. Also cotton "pipe cleaners" are useful for poking through the ball holes. Rinse off the fluff after though.

Acetone will remove remains of superglue on the diff plates. You can then sand them flat on a flat surface with say 600 grit wet and dry (with a couple drops of water) This will improve any "scoring" and give you a smoother action.

Replace the balls and the thrust bearing. Don't forget the little disc springs too, these will stop it working loose again and the melting.

Sorry if you already knew all this. I race my Procat and the diffs run great, so far, touch wood etc etc

[DerbyDan]

Well the Hex diff was certainly a worthy upgrade.... that and the metal 'caged' thrust race (I don't think the latter was a schumacher part?)

Anyway i'm not sure if the hex diff became 'standard' on the Cougar, it certainly isn't shown in the manual....

http://www.tamiyaclub.com/manuals.asp (pick Schumacher Cougar from the drop down menu... the diff assembly is shown on page 11 )

P.S; glad you signed up on Oople - as you say its well supported internationally & theres quite a vintage following on their too

[RCveteran]

Got it, I see now the hex was an upgrade not a standard. All good ideas, on rebuilding the diff. I have rebuilt a gazillion JRX2 diffs, these are a bit different but seems the same basic principles apply.

I have some ceramic balls on the way and will use the Losi thust bearing with three belleville (spring) washers. I do sand the discs with 600 grit as well, I use Schumacher ball diff lube and Associated black grease on the Thrust Bearing.

This formula has worked well for me in my JRX2's which now run brushless.

One thing I need to know though, what do you use for replacement friction paper and glue on the stock diff?

[8rad]

CA

[Asso_man!]

CA

Yep that is what I remember using when building it 20 years ago. I never understood the choice of using sand paper in a ball diff, that stuff loses sand and it goes str8 into the diff lube... Anyway, I think your best option is to go with a fine grit and try to cut some new rings out of it using a diff ring as a template. I am not sure, but I might (key word here) have some left somewhere in my boxes.

[RCveteran]

That was my plan, to use some 1000 grit or something and cut some out. If you have some it would be easier.

[dangermouse]

I used to use Jrx2 diff rings BITD with the hex diff in my Procat. The Losi diff rings slip straight on to the hex diff carriers and are a lot harder.

[RCveteran]

I didn't even think to check that and I have a ton of Losi hex rings, thanks for the tip.

[RCveteran]

What other differential evolutions were there on these early aluminum pan cars. Did the hex diff ever become standard on the Cougar, Cougar 2 / Team, or Cougar Works? Founds some threads about an MMS transmission, any more info or a good link on this would be appreciated?

Also want to find a suitable replacement drive belts, I know it is 72 teeth, 5/16" wide, and I believe this is the guy. Anyone try these?

https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=41981&GroupID=213