MotorBreathLT1

No fancy story, took a jump trying to show up my neighbor and his aftershock, landed fine and all, but the rear pinion gear pretty much shattered when I hit. Haven't even gotten through my first gallon yet lol.

I want to make the diffs as solid as possible for a reasonable price, times are tight right now so the less I spend the better. I know of shimming and what not but I'm confused of the best bang-for-buck option is in terms of a new gear-set and I would love some opinions.

I'm looking into this, http://www3.towerhobbies.com/cgi-bin...I=HPIC0269&P=K . The HPI "bulletproof" 29/9t, i see this is a slightly different ratio than stock so I would of course have to do the front diff as well, which is extra money (I plan to do the front diff as well but I'd like to put it off if I can.)

Or could I get away with this? http://www3.towerhobbies.com/cgi-bin...2&I=LXTSY7&P=K . It's stock ratio so I could run it with my stock front diff (which would break and or get replaced sooner or later), but would it be wiser of me to go all out for the "bulletproof" gear set? Right now its a stock f4.6, might upgrade my tuned pipe later on but for now I don't see any major engine mods/changes coming soon.

Also, I see they come with shims, would I still need to buy a separate set of shims to shim my diff? I also hear alot about aftermarket diff cups and cases; can somebody enlighten me with some info and links? Thanks!

-SomeGuy-

I think HPI has an offer to upgrade broken diffs with the "bulletproof" diff they have for the flux and XL. The reason your diff broke is because you either had the throttle on or the brakes when you landed your jump, always let go just before it hits the ground.

Contact HPI about your diff before you look at spending any money.

jbooker82

My Feedback: (4)

If you need to say with the stock ratio for now then dont use the heavy duity ones you have a link to. Use the Super Heavy duity ones. They come with a larger bearing for the ring gear. Then make sure you shim them tight with no binding. I have been running those diffs for 5 gallons with no problems. A good tight shim will make them last much longer.
http://www3.towerhobbies.com/cgi-bin...&I=LXWUZ7&P=OW

steed2-inactive

I completely agree...take the extra time to shim them up properly and they will last forever..( with routine maintenance and no hard on throttle or brake l;andings)

MotorBreathLT1

Thanks for all the info guys.

Yeah, now that I think about it I may have let off the throttle too late, ah well; live and learn.

rotzilla

learning to jump can be very expensive....

MotorBreathLT1

What shim set do i need with the super Heavy Duty gears?

CR500rider

the gears will come with a set of shims. at least my BP diffs did

MotorBreathLT1

I just got off the phone with HPI, they said I am covered under warranty but they only upgrade older models of the XL and flux line to "bulletproof" diffs, so I will get stock replacements. What I'm confused about is he said I would get Super Heavy Duty gears, when earlier in the call he said I would only get stock gears. Did my truck come with the SHD gearset?

I have to email pictures, I'll see if I can get a part # of what they will be sending me.

jbooker82

My Feedback: (4)

The Super Heavy Duity gears are the ones that came out before the Bullit Proof gears. With the bullit proof gears you have to do both the front end and rear end because they have a different gear ratio. The Super HD gears are the same ratio as the stock Savage X gears. They are made out of a different material / better heat treating to make them tougher. The ring gear in the Super HD gears has been machined down where the bearing slides on. This allows them to use a larger / thicker bearing.

Here is a pic.

X diff cup, X Ring Gear, Super HD Ring Gear.

MotorBreathLT1

That's what I thought, the way the rep worded it was pretty confusing. Thanks for clearing that up.

jbooker82

My Feedback: (4)

Just make sure you shim the diff. I shim mine until it start to feel notchy, then take 1 shim out. Every diff issue (one front and 1 rear) I have has was do to the bearing failing. You wont break pinon gears nearly as bad if you do a good tight shim job. And with the Super HD gears I havent had a bearing failure yet. I did ditch the HPI bearings in favor for Boca Green Seals.

MotorBreathLT1

Well I just got an email back from HPI, turns out I'm getting 2 sets of the bulletproof diffs for free =D. Thanks SomeGuy for suggesting I call and ask about warranty, saved me like $80.

Nesal

Congrats!!!