Shimming Savage Diff's?

[olds97_lss]

I tried a search for this the other day and all I found was t-maxx references.

Does anyone shim thier savages diffs to get better life out of them? If so, what do you shim in them? I couldn't hardly find any slop inside the diff cup or anyway to shim the diff as a whole. The only place I have slop is where the pinion rides on the ring gear, but I can't do much about it as the cvd cup takes out almost all of the slop. I could maybe fit in a .5mm shim behind the pinion to get it to ride deeper on the ring gear, but that's about it.

 

[sweetdiesel]

Here ya go

http://www.savage-central.com/ftopic24692.html

I haven't done mine yet since they are still holding up but I will do this on the next rebuild.

 

[olds97_lss]

Is he shimming the actual outside race of the bearing to the side of the case? Weird... I don't think my stock cases even have any movement side to side. The only thing that can move is the pinion gear, and I can only move it about .5mm at most before the cvd is rubbing on the bearing.

I replaced my diff case because the bearings were actually moving in their seated positions. With the new case, the bearings had to be pressed pretty hard to get them seated and now there's no movement. I also replaced the bearings as they were loose inside.

I've run 7 gallons through those bearings and housings and I don't know how much skymaxx ran through them before I replaced them.

 

[sweetdiesel]

I wonder if the reason why your diff case became damaged was due to not being shimmed. That slight bit of side to side movement over time and rotation might have wore down the plastic? I bet if you had kept going with that damaged case you would have eventually eaten your bevel gear or chipped some teeth off your ring gear.

But....since you ran 7 gallons+ on your current diffs I wonder if shimming would be worth the effort?

I know my spyder gears used to last just a few tanks, even with the 4 spyder mod, but that was back when I was still learning to drive the truck and thought WOT landings were cool. My current set of diffs have just a tad over 2 tanks. They are starting to go out but I'm still deciding on aluminum diff cups or sticking with stock. Hopefully I'll get at least another gallon on them before they bust.


What diff cups are you running now olds? 7 gallons is a loooooooong time.

 

[olds97_lss]

Sky maxx had just done the 4-spider mod before he sold it to me.

I ran 5 gallons with an Omega 21 Comp (2.4hp) before I had my first diff failure. The screws holding the ring gears on were the coarse threaded ones. I replaced the cups, one ring gear in the rear and one pinon gear in the front. I also used machine screws and light oil (7K).

This week, I'm just doing preventative maintence for the upcoming bashing season. Going over all the wearable items on the truck like bearings, cvd's, shocks, diffs, spur gear, steering linkage, turnbuckle ends, arm hingepin holes...

So far, the following have been replaced:
Front bulkhead
Rear bulkhead
Rear hinge pin brace
Rear diff bearings (all 4)
Rear diff cup
Rear diff case

Front diff was ok and so is everything else. Not bad for 7 gallons of pretty hard abuse. Although, I did replace a couple c-hub uprights last year.

 

[1 Bad STi]

Great write up on that, I wonder why HPI cut the costs to do it, or what that deal was.....

I know that all higher end buggies feature this...Try it out OLDs and let us know how it goes.