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DOGPILE

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Hello again, I have posted this problem once before and followed all the advice given but still the problem keeps coming back.

The problem is, i have just upgraded my .21 to a .26 along with the ribbed SS tuned pipe, the engine rips the snot out of my other trucks but it also eats diff gears for breakfast. Been running this Picco mill for 3 weeks and have got through 4 sets of spider mods and 2 tubes of threadlock due to so many rebuilds.

Have tried various gear setups like 49 fly and 16t CB etc. at the moment i am running on 52 spur and 18t CB with 3000wt oil in the front diff and 5000wt in the rear, have not even started tuning the engine yet, its still at FS, very rich but the power is mind blowing, this truck has more power than my lawn mower.

Bought new diff cases for front and rear thinking that the spider mod would feel better in a new house, have used both new cases on the rear so far cus its only the rear diff that keeps popping, also tried various oil ratios but still can't use my truck for more than 5 mins without blowing the rear diff.

Please help cus my pennies are running out and so is my patience.
 
That is pretty puzzling that you are still eating up bevel gears.

With the engine off, does the truck roll along on the ground (about 10 feet) with no problems?
 
So far I have had no problems with my Picco .26. It is the ONLY upgrade I've done so far and nothing has broken but I have eaten a spur gear. I'm running 49/18 and it absolutely FLIES!!!!
 
Dogpile 52 spur and 18 cb does not work together look at HPI gear chart. This could be why the diif wear-out
 
I don't know the savage at all, so I apologize for my ingnorance, but is there a slipper clutch that you could loosen up a bit? That way your clutch is taking the beating instead of your diffs.

I run a 21 maxx with the clutch set to slip some because I was running into the same kind of issues. Once I got over the fact that wheelies are only hard on the hardware, I let the clutch take the brunt of the torque. It's still fast, but you can hear the engine when the clutch stops slipping about 5-10 feet into a hard romp.

Since I've done this, I haven't blown a diff in 4 gallons.

Just a thought.
 
I had the exact same problem as you dogpile, when i upgraded to a wasp .26.
I switched to a 49 spur, 18 cb, and loosened my slipper just a tad and I have two gallons so far with no problems. Hope this helps you out.
By the way--I still have tons of low end if your wondering about the larger cb.
 
I was running 18/49 with a wasp and the spur gear tightened almost all the way down and it didnt bust my bevel gears, just like three spurs (plastic). Make sure that you use only HPI gears. i had the same problem with blowing the diffs in 5 min. Cuz some one told me that i could use the ofna or kyosho gears, NOT TRUE. they look the same but are not!

Is the Diff case eaten up or are the gears just stripped? Are the screws on the ring gear backing out? Maybe i just missed it but did you do the 4 spider gear mod?
 
Thanks for all your help again, i will loosen the slipper a little and see what happens. That Savage diff locker looks like a good idea, might see if i can get hold of some of those. Thanks again.
 
I would avoid putting it in the front diff. I know if you lock the front, it makes steering really crappy.

I have the rear locked on my 18 SportMaxx and it's a pain to handle, but it's fun.
 
You might also try replacing the diff bearings, bo32 10x16x5mm. I had a problem with my rear diff after rebuilding it and it turned out that the bearing was failing allowing excessive movement in the rear end causing the pinion to skip the bevel under power. I replaced them and all is well for the moment. I do however plan on using all alloy components in the rear end the next time I rebuild which will probably be pretty soon. I'm going to replace the diff cup, gear box and bulkhead with longevity in mind.
 
Thanks for that PuffnStuff, i have already changed the bearings.
 
Hmmm maybe it's time for the wiggle test. I used to wrench on cars and Ford recommends to run a wiggle test on things when you can't figure out what's wrong. Have you also taken apart your tranny and inspected everything in there. This shouldn't be the problem. Also how is your ring and pinion gear going into the diff???
 

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