diff gears

[Kaz the Minotaur]

I opened my read diff, to change the fluid, and noticed that there is only 1 pair of planet gears in the rear diff. The shaft is notched to accomodate a 2nd. pair. The case also has the slot in the side. I would think it to be stronger with 2 pairs.


Does your have 1 pair or 2?

 

[auto2]

one pair. i never thought of a second pair . interesting.

 

[Obeast44]

They are the same diffs in the TT/MT, which have 2 sets. They only went with a single set to save weight in the lighter X series Rampages.

 

[Kaz the Minotaur]

Seems kind of wierd to me though. I wouldn't think there would be that much weight savings.

Has anyone broken the planet gears yet?

 

[Obeast44]

I haven't heard of any of them getting munched since the TT/MT v1 days.

 

[killajb]

Interesting... I don't think it has much to do with weight savings as much as heat maybe. The extra two planetary gears and shaft wouldn't seem to cost much either, so I doubt it was to keep costs down.

My converted Muggy gets the diff temps up pretty high, especially the center diff. Maybe two less planetary gears plowing through oil on the main gear were found to be strong enough without generating as much heat due to less friction. A solid center diff as well to avoid any possible issues there.

 

[Kaz the Minotaur]

Well I guess we will find out if it is up to the 5692 on 12S! lol

 

[killajb]

Gassers use four gears (TT,MT) but consider the characteristics of performance: Do you expect to break the tires loose with the gassers as much as an electric would? Generally.. I'd say no.

My Muggy's center diff heated up so much because under acceleration, the center diff would be forced into action (even with thick plumber's putty as my diff lube), spinning the planetary gears around and forcing them to chugg through all that slime. When my Muggy ran the gas motor, there wasn't enough low end torque to strain the center diff as much.

I assume the same applies to the larger scale gassers. I believe they all have a solid center diff. Excluding that from consideration, under heavy acceleration, the only "give" would be either through loss of traction, or the front or rear differentials.

I'm concerned about the stock diffs holding up to larger wheels and tires, as well as more power. It will be interesting to see what happens when adding an extra pair of planetary gears. Things could heat up enough to cause the plastic diff casing to distort. Converesely, I think shimming the stock diffs as they are could help to prevent any failure without introducing as much heat.