Savage Diffs
 

Now that we have the bullet proof diffs, the only weak part of the diff is the 10x16x5 (B032) bearing. I've tried milling down the stock diff case to accept the 8x16 bearing and that works, but this weakens the shaft and it snaps off after a few packs.

Solution: After much digging, I found out the Vorza Flux diff case will fit perfectly. It's actually a Hot Bodies part number from Lightning Series truck (HBC8019). Yes, this is a plastic diff case, instead of aluminum, but it has a steel ring at the end that accepts the 8x16 bearing. The diff case is very rigid plastic, and seems like it will hold up well. An added bonus is that the plastic will not let the screws back out. I've had hit or miss success with loctite on the stock diff case because of grease getting into the holes, but that will never be an issue again. The Savage diff internals fit perfectly, however, you will need to sand a few thousands off of the length of the cross pins to get them to slide in easily. Everything fit nicely and the diff is smooth as silk. I am very happy with this upgrade and will never use the 10x16 bearing again.

Based on what I've read, the Kyosho Inferno and Hot Bodies D8 diff cases and internals are also direct drop in parts; I have not yet confirmed this.
Attachment 9636Attachment 9639
Here's another tip: If you've ever wanted to reverse the direction the motor spins and still go forward, reverse the diffs. All you have to do is grind off the little tab inside the bulkhead and then you will have the option to install the diffs in standard or reverse orientation.
Benefits:
1. Motor spins reverse direction which will cause the pinion to push up against the stop if it ever loosens . . . no more pinions falling off.
2. The reason I decided to try it was that I noticed that my truck was running quieter in reverse than forward . . . probably due to wear on the transmission gears. Now I'm using the other face of the gears so I'll get more life out of them.
3. It's cool to have options.:yes:
Attachment 9640Attachment 9641

sounds like a good way to get rid of that stupid bearing! Let us know how the plastic case holds up.

If you want to reverse the rotation of the motor just hook the esc up to CastleLink and reverse the rotation

please let us know how the plastic case holds up... im worried it will allow flex and cause gears to shred...??? but nice1!

Yes it would, or swap a motor wire. What he was referring to was running the center drive line in reverse while the rc moved forward.

wouldn't running the motor in reverse also help eliminate the slipper nut from coming loose?

That and flipping the diffs to ensure the truck goes the correct direction when the motor rotation is changed.

well im glad you have had success!

as you know i am now taking the plunge!

I definitely think the vorza cups will handle the hard starts and large jumps as there are no on throttla landings... i bet back flips will be fine too!

I have never heard about loctiting the bearings to the cup or ring gear, and i prob wont bother as i the 8x16 on both side should last a long while in my non flexing alloy bulks anyway... But it is a weird though... if it has worked out for you so far, maybe its ok?

Loctite seems like a decent idea. We do not want the inner race turning on the ring gear or diff cup, as that will cause metal to metal wear and slop.

I am glad you are having success with the plastic cup. I blew up alot of those in my old savage with the 14xl and 8s. But I never had an issue with the 10x16 bearings... Whatever works, thats ok with me!

hmmm... well from what i remember of seeing of the old savage plastic cups, these vorza ones seem much better and definitely very solid. Only time will tell with my 9s setup. Maybe they will do all right in the alloy bulks? maybe they may not cope with larger baja wheels i hopefully upgrade to when funds allow. I just dont want the larger 8x16 bearings to fail nor the internals of the diff. Only time will tell.. when and if they do fail or show obvious signs of distortion, i will upgrade to the IRC lightning alloy cups. but for now, these seem very solid

Jahay, Im trying to fit my rear bulletproof diff into some GH alloy bulks i just bought (truck is dissasembled) and the GH bulk halves wont close with the bulletproof diff inside. The bulks close up fine without anything in them, but when i try to close them with the diff inside, something is fetching up or rubbing and making it so it wont close. I dont think its the ring gear itself because when i turn the ring gear (while inside the alloy bulks) it does not make the tick tick tick tick sound it would make if the gear was hitting the alloy bulk.

Any ideas?

Thanks

I had this issue recently with GH bulks and brand new BP diffs out of a XL. Turned out the case was not machined correctly and was not the correct shape to fit one of the diff bearings. One of my cases fit fine and the other required some shaping with a round file. Have a look at the bearing areas on the case when you have the diff in. I had what can best be described as a flat spot. Should have been curved to match the bearing.

I'll check this out and let u know what i find. Thanks!

I had this prob with one of my cases too... and when i screwed it up tight and my mesh didnt allow the gears to turn....

hmmm i found that my HD Diffs (original diffs in flux) worked very well and were smooth... when i put my BP diffs in teh GH Bulk.. there was a lot of friction. Many i know who use GH Bulks with brushless systems say it is unnecessary to use BP Diffs as the mesh is always constant anyway.... and i some what agree... but i wanted to use my BP ones which i paid more than $50 for haha

I didnt think i had a prob with my bulk but the mesh was definitely too tight... i attached my drill to the end of the pinion after tightening the bulk up with the shock tower in there) and the gears then used my drill to turn the pinion and spur for a good 5 minutes, the mesh had bed it self in. Now my diff turns extremely smoothly...

OK guys I figured out my problem with the BP diff not fitting in the GH bulk.

I was using some honkin' 6x15x.2mm shims to shim between the bearings and the outdrives. The bearings sit very squarely and snug up against a little wall in the alloy bulks, and when I would go to close the bulk cases there was no room for a 15mm O.D. shim beside them, so they would protrude and make it so the case would not close all the way.

Lucky me, I brought home a file and an oil stone today from work, just for this job. Well I did not use them on the aluminum bulkhead like I figured i would. I ended up filing down the 15mm O.D. shim to match the O.D. of the outdrive so it wouldn't interfere with the bulkhead. Problem solved! (Yes, i filed down a shim :lol: )

Now I have a new problem.. I finally got a perfect shim set-up so the diff spins freely and there is just a hair of play between the pinion and the ring gear. To achieve this though, I now have NO shim between the bearing and the ring gear. As soon as i put a shim there, the pinion/ring are louder when spun and just overall dont sound right.

The bearing in use is a metal shielded Boca bearing and it is the beefier of the two (8x16x5mm) for what its worth.

Will this set-up work or is the bearing going to blow out? Is there a way to get the ring gear away from the pinion without removing this shim?

Thanks a lot guys!

I do not have a savvy diff handy but I do not think that shim is needed?

Does the bearing race (outer part that remians stationary) touch the ring gear? If not then you are good to go. The X manual calls for the shim to be there, but that is for the plastic bulks, and it is likely there so you can remove it and place it on the other side to get the mesh right after something wears, or vice versa.

The inner bearing race (red arrow) will be in direct contact with the raised area pointed to on the ring gear w/ blue arrows.

http://img.photobucket.com/albums/v2...c/ringgear.jpg

Thanks

That is fine, just as long as the outer race is not in contact with the ring gear.

shmming in a GH Bulk? i didnt have to shim at all? it was perfect... any shimming just caused binding in my bulks...

HAHA YOU GROUND DOWN A SHIM!!! never done that before... at least you found the culprit!

Wait wait wait.. You didnt need any shims at all? not even the amount that comes on the diff from the factory?

Thanks for re-insuring me lincpimp :yipi:

no i didnt... neither did Frddy on HPISF... I originally did shim, but didnt actually find it necessary....

But if you feel you requre it, then go for it. Everytime i reinstall mine and when rebuilding my diffs, i always make sure that my diffs either need or dont need shimming.

Wow, i was under the impression that at least one shim was necesary between the bearings and the surfaces they were contacting to prevent wear or something. Think i must've read it somewhere on a different forum.

Thanks for clarifying!

:smile:

Just took the shims completely out.. You were right!!! The diff fit perfect, perfect mesh, perfect amount of backlash, etc. Thanks man!

it is all good bud! Happy to help! Gd luck with the diffs holding up! Im just rebuilding mine now.

Thanks..

I've actually only got to run my flux a total of about 10 minutes all together since i've owned it.

Blew out the whole tranny within those first 10 minutes on 6s. Also stripped a wheel out and pulled my receiver wire out!! This all happened last summer. I lost interest for a while after that experience.

Im just now getting around to tearing it down and bulletproofing it and to my surprise, Im really enjoying it.. Cant wait to run it!!!

:intello:

i love running my truck...dont get me wrong... but there is something better about piecing a truck together!

It is definitely a blast! Especially when you have a bunch of upgrades from different companies and none of them fit together like they're supposed to so you have to improvise :lol:

Check out a little custom work i just did.. I am a beast with a file :tongue: No more nubs.. Needed to get rid of them to fit my bashcat braces.

http://img.photobucket.com/albums/v2...c/IMG_1533.jpg

http://img.photobucket.com/albums/v2...c/IMG_1534.jpg

Now i need to order some M4x40mm caphead screws. The ones provided in the Bashcat brace kit are the right size if you're using stock bulks.. But the outer bulkhead half of the GH set is not even threaded! So i've got to reach a bit deeper with my screws. Im also going to have to open up those un-threaded holes on the GH bulk half as im getting some binding/rubbing there with my screws and its rounding the crest of the threads all to hell.

When will the orders for this thing stop? lol The post office is getting sick of me :whistle:

hehe aluminum bulks and bashcat braces.

talk about overkill bulletproofing.:party:

Only the rear bulk is aluminum. Im trusting your braces to keep the front plastic one together :mdr:

Very impressed with the Bashcat braces! There is literally no way in hell I'll be able to break or bend these. Fitment is dead-on as well. Thanks again Mr Snuggles!

I was so close to buying these braces... they are awesome and to see a kit put together by an SC member is awesome... so many people talk about doing things, and nothing ever materialises. SO BIG PROPS TO MR SNUGGLES!
if i wasnt carrying out the new LST Hub mod, then i would be getting these... Need to make my own thicker, wider braces...

ljon, any updated pics of the gh bulks and braces?

Here ya go...

http://img.photobucket.com/albums/v2...c/IMG_1535.jpg

http://img.photobucket.com/albums/v2...c/IMG_1538.jpg

http://img.photobucket.com/albums/v246/ScMc/bc.png

oooh shiny, can't stop staring.

are these aluminum bulks quick access like the x bulkheads?

They have a front and back case like the quick access bulks but Im not sure if the front case comes out exactly the same as stock.

Im kinda doing a mock-up build right now just to make sure everything fits right and i know the correct order to put everything together in.

Then im gonna tear it all down to grease stuff, threadlock metal on metal and CA metal on plastic as i build it again from the ground up.

I can let you know how much of a pain they are to take out when i tear it down but I dunno when that will be exactly. Hopefuly another GH aluminum bulk user will chime in with an answer for ya.

Not quite as easy to get into as the X bulks. You have to remove the pin brace bolts on the bumper side, remove the 2 bolts that hold on the plastic skid plate closest to the bumper, remove the shock tower bolts and the 2 smaller ones below them. I like to pull the upper arm pins out.

These are sturdy parts, iff you shim the diffs correctly the only reason you will have to remove them is to change diff fluid.

Update
 

Up to about 30 runs now on the Vorza cups. I noticed the ring gear side bearing had some lateral play between the inner and outer sleeves on the front diff, so I swapped it out. While I was in there I decided to degrease the internals and give them a close inspection. I compared the used internals to some new ones and there was no discernible difference, even at the highest magnification my camera would allow. Guess that lithium grease works WELL!

There was a very slight amount of scoring inside the cup from the spider gear shims spinning, but not enough to warrant replacing the cup. I also noticed a small chip in one of the slots (probably from an air bubble getting into the mold during manufacturing. Just for kicks I replaced the grease with some STP Oil Treatment before I sealed it back up . . . curious how that will do.

http://i1116.photobucket.com/albums/...n/IMG_2886.jpg

http://i1116.photobucket.com/albums/...n/IMG_2884.jpg

Gear on Left is new, gear on right has ~30 runs
http://i1116.photobucket.com/albums/...n/IMG_2882.jpg
Gear on Left is new, gear on right has ~30 runs
http://i1116.photobucket.com/albums/...n/IMG_2881.jpg

Final Update till something breaks
 

Took the rear diffs apart, and they are in excellent condition as well. Only difference, is no small chip in the slot. :yipi:

Went ahead and replaced the grease with STP Oil Treatment in these as well.

thanks for the detailed images Jason!!!

Gives me a lot more confidence that they will hold up to the 9s power in my alloy bulks!

So surprised that there seems like there is no wear...
I guess if it all works correctly and installed properly, there really shouldnt be any serious wear

Lube
 

I'm surprised to. I think it's all about what lube you run in them, and of coarse proper shimming. I know there are those that disagree with this, but I think grease and thinner diff oil, is much kinder to the gears than diff locking oil. Issue with thinner oil is it sneaks past the o-rings quicker. However, diff oil is a necessity if you need to tune your truck for racing or partially lock your diffs for climbing.

Grease is a win win for me because it keeps the gears happy and doesn't leak out. I'm curious how the STP stuff will work out . . . who knows, I might even like it better. :oops:

I recently tore my diffs apart again and filled the rear/front with 30k/50k about 3/4 full in the diff cup. Then put a nice glob of STP oil treatment in them to fill up the the rest of the space. This stuff is a lot thicker/goopier than i thought. Hopefully it treats the gears well!

I was tightening one of the diffs when near the end i heard a little crack.. My torque-o-meter tells me I wasnt using excessive force.. The stock cup is just straight up weak and made out of soft material.. (aluminum is soft in general but HPI's is like butter) So needless to say, there goes my extra diff cup I had on hand. Will be purchasing the Vorza cups very soon.

http://img.photobucket.com/albums/v2...c/IMG_1660.jpg



Question: So the stock diff internals drop straight into the vorza flux diff case.. literally no difference in shimming or anything?

Thanks

ljoncp, The stock spider gears, cross pins, shims, etc. are a direct drop in. The Vorza cups are actually a hair smaller inside than the stock cups, so you may need to sand a few thousands off the length of the cross pins. Do a test fit first ofcoarse.

This has nothing to do with useing the Vorza cups, but I have recently started to shim my spider gears (both the 2 large ones and 4 small ones with an extra washer). You will have to experiment with this to get the perfect fit. You may be able to fit an extra washer behind all 6 gears, and you may only be able to fit one be hind just the 4 small ones. The idea is to get the mesh as tight as possible without any noticable extra friction. You won't be able to tell for sure if the mesh is right until you have screwed it back together (2 screws should be sufficient for doing the test fit).

I am blown away by how long my diffs are lasting! I run the truck for at least 2 packs almost every day, and although I am a sensable driver I don't baby this truck by any stretch of the imagination. I used to go through diff cups, bearings, and spiders like crazy!