Striped Diff

[Java*]

So... I stripped my rear diff today on my xl and I was pleased to read about the heavy duty differential set from hpi I could get, but then I was not so pleased to find out I already had them 😛

The only piece that stripped was the gear that has the rod attached to it in this picture http://www.smfstore.com/product_info.php?products_id=2007 . I guess its time to strip the front end and make sure its shimmed right. Nothing else was damaged accept for that one gear so I'm debating whether I really need to upgrade the dif or just replace it. Any help will be much appreciated! thanks guys!

 

[Jeremy]

You should replace the ring gear and pinion tooth both at the same time ... And yea SHIM Them open the front up like you said and shim that also .. replace the lube in the diffs while your at it .. I run 30,000k in front 50,000 in rear

 

[Java*]

Time for a rebuild 🙂 thanks jester for the help

 

[Jeremy]

Need help!! No problem man Let us know

 

[Java*]

jester I read your sticky post on diff shimming, and just to clarify it says to use Mugen 5,000wt Silicone Differential Lube (for Rear differential) Mugen 7,000wt Silicone Differential Lube (for Front differential) and Mugen 50,000wt Silicone Differential Lube (for coating the outside of the differential assembly) is the 50k and 30kwt you spoke of in the above post for lubricating the outside of the differentials? sorry just a bit confused

 

[Jeremy]

I just use good old black bearing grease for the lube of the ring/pinion...

I run 30k in front and 50k in the rear .. I like that set up

 

[zud00]

Does the XL have plastic diff cups or alluminum diff cups? If it has plastic, maybe the flex allowed some slop in the gears.

 

[THE JUDGE]

The Xl has the same aluminum cups as the X 4.6, they just have the hardened diff gears too.

I have already heard of quite a few people who broke the diff gears already on their XLs, more than one would expect really. It makes me wonder if HPI didn't heat treat them properly and made them wayyy too brittle...

 

[zud00]

Maybe the 5.9 just has too much power. I have the machine hardened diffs in the front and rear and haven't had any problems yet, although I have about a half gallon run on them. I hope I don't strip them because I'm tired of repairing them.

 

[Java*]

for now the only gears Ive stripped are outside of the dif cup. Hopefully I don't strip anything inside for a while to come 😛 Well see how long this holds up.

 

[Java*]

before I start driving on this I had a question. I shimmed the diff so there was very little play side to side (barely noticable) I was just curious, using 50k for the rear I imagine it should be harder to rotate than it was before, and this will allow for the wheels to spin more evenly correct? Just want to be sure before I start beating on this again hehe

thanks

 

[Jeremy]

if it is a brand new diff .. remember you have to break them in for a tank or 2 .. do some figure 8's

 

[Java*]

they arent brand new, I just replaced the orings, diff fluid, ring and pinion tooth gears, and shimmed them. I still plan on running soft at least a tank though. Thanks jester!

 

[Pineapple]

That's brand new then-new ring and pinion. Try to shim them just a little tight so when they break-in (or wear in really) they will have just a hint of play between gears. Quite like a spur and C/B play.
Last time I did mine I thought they were too tight but I cut an old dog bone and put in my drill and ran in diff on bench to wear in for 15-20 minutes and they ended up perfect. Plus I didn't have to baby the truck for a few tanks. Just make sure drill is turning the right way.

 

[Java*]

thanks pine Ill do that! thanks for all the help guys!