Kraton How many shims are in your gearbox?

[AjDale]

Just shimmed up my rear diff on my “stock” Kraton XL. I have 5-6 shims behind the input gear and 2 on the side of the ring gear. It was incredibly sloppy, now we’re back to good as new. How many shims do you use in your gearbox?

 

[Sandracer_NL]

It varied from car to car.
I usually use 1 or 2 (0.15) shims on the side of a diff, and between 0 and 0.3mm behind a input gear.
5 or 6 shims behind the input gear sound like a lot! How much mm in total did you shim?
I’ve never heard anyone needing that much shimming, did you check if your diff housing is still OK?

 

[332_RC]

It varied from car to car.
I usually use 1 or 2 (0.15) shims on the side of a diff, and between 0 and 0.3mm behind a input gear.
5 or 6 shims behind the input gear sound like a lot! How much mm in total did you shim?
I’ve never heard anyone needing that much shimming, did you check if your diff housing is still OK?

Same here

 

[sumguy75]

I've never used more than 2 shims on the side of the diff, never any on the input gear.

 

[Johnny b]

4s kraton came with 1 on ring gear side and none on input. Mesh is perfect with no slop.

 

[AjDale]

It varied from car to car.
I usually use 1 or 2 (0.15) shims on the side of a diff, and between 0 and 0.3mm behind a input gear.
5 or 6 shims behind the input gear sound like a lot! How much mm in total did you shim?
I’ve never heard anyone needing that much shimming, did you check if your diff housing is still OK?

2 shims on the side of the ring gear, I send my rigs pretty hard and am very harsh on the throttle. Every Arrma 6s rig I’ve ever owned I’ve had to shim ever input gear significantly. This one I just used 13x16x0.2mm shims for the ring and pinion gear. I stuffed 5-6 of them behind the bearing that holds the input gear in place. It’s meshed perfectly now

 

[AjDale]

4s kraton came with 1 on ring gear side and none on input. Mesh is perfect with no slop.

Sounds about right for a 4s, my 6s rigs have shims behind each input gear

 

[RC Steve]

One 8x12x0.2mm shim behind my drive side bearing. If I need a second shim I'll only need 1 so I won't be fighting a stack. The diffs seat better without the exterior shim and are easier to install. Since doing this I haven't had the need for a second shim. I don't understand why putting the shim behind the bearing instead of in front would dish the ring gear in more, but it does.

I also have one 0.2mm shim behind my input gears (EXB diffs). All my 6s trucks are set up the same.

 

[RC Steve]

2 input gear shims will cause my input gear to drag on my diff case. I question whether you diff is seated all the way in your gearbox.

 

[Johnny b]

I need 2 shims in left hip and 1 in right knee. Lots of slop.

 

[AjDale]

Everything is definitely seated properly, feels the best it has honestly

 

[Dan B.]

Everything is definitely seated properly, feels the best it has honestly

I’m glad you got it good, but no, that is not in any way normal to have to use that many shims to get proper mesh. 2 shims on the ring gear side isn’t unheard of at all, but 5-6 shims behind your pinion/input gear is way outside of crazy. Are you running stock input gears? If they’re an “upgrade” pinion than they’ve been poorly machined, or they’re just simply the wrong ones. If not, I’d replace your bulkheads for sure because there is some really excessive wear in that area.

 

[AjDale]

Strange,

I’m glad you got it good, but no, that is not in any way normal to have to use that many shims to get proper mesh. 2 shims on the ring gear side isn’t unheard of at all, but 5-6 shims behind your pinion/input gear is way outside of crazy. Are you running stock input gears? If they’re an “upgrade” pinion than they’ve been poorly machined, or they’re just simply the wrong ones. If not, I’d replace your bulkheads for sure because there is some really excessive wear in that area.

I thought it was an excessive amount myself. My pinion gear was beyond sloppy and the outside bearing was pretty much falling out. They’re stock gears. EXB gears actually. I think the bulkhead is just genuinely worn out. I’ve sent this rig harder than ANY other rig I own. The gearbox was used prior to me building this rig as well. I’ll run it as is and see what happens. I’ll work on getting a new diff off Jenny’s most likely

 

[Dan B.]

Strange,

I thought it was an excessive amount myself. My pinion gear was beyond sloppy and the outside bearing was pretty much falling out. They’re stock gears. EXB gears actually. I think the bulkhead is just genuinely worn out. I’ve sent this rig harder than ANY other rig I own. The gearbox was used prior to me building this rig as well. I’ll run it as is and see what happens. I’ll work on getting a new diff off Jenny’s most likely

Your diffs are probably fine, I’d just replace the bulkheads. Do you the newest Kraton EXB, or just a Kraton with EXB diffs? Because even at Jenny’s the replacements are super expensive.
https://jennysrc.com/collections/ar...fferential-ebs-ara8708?variant=48433375248661
You could get some very good aftermarket bulkheads for less. I think everything is the same as the BLX bulkheads except for the output bearing sizes? Don’t hold me to that…

 

[AjDale]

Your diffs are probably fine, I’d just replace the bulkheads. Do you the newest Kraton EXB, or just a Kraton with EXB diffs? Because even at Jenny’s the replacements are super expensive.
https://jennysrc.com/collections/ar...fferential-ebs-ara8708?variant=48433375248661
You could get some very good aftermarket bulkheads for less. I think everything is the same as the BLX bulkheads except for the output bearing sizes? Don’t hold me to that…

Diffs are definitely fine, I think the bulkhead is worn/stretched out. I’m just running stock plastic bulkheads on this rig nothing fancy. I may just grab a new plastic bulkhead or I’ll go aluminum with Treal or something along those lines..

 

[Dan B.]

The ADU ones look great for the money. I think they’re on Amazon/E-Bay now too, but here’s the other link.
https://www.aliexpress.us/item/3256...=scene:pcDetailTopMoreOtherSeller|query_from:

 

[sumguy75]

I installed aluminum gearboxes front and rear on my Notorious. Cant remember the exact weight difference, but they didnt add much weight at all. I'll probably do that for my Talion too.

 

[cmoney]

The ADU ones look great for the money. I think they’re on Amazon/E-Bay now too, but here’s the other link.
https://www.aliexpress.us/item/3256805082925668.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.1.290b5tsA5tsARf&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=913bee7f-710a-4688-b592-2024a024ee68&_t=gps-idcDetailTopMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:913bee7f-710a-4688-b592-2024a024ee68,tpp_buckets:668#2846#8116#2002&pdp_npi=4@dis!USD!72.04!72.04!!!510.95!510.95!@210313e917306024885488543eeba1!12000032426503879!rec!US!4458253315!X&utparam-url=scenecDetailTopMoreOtherSeller|query_from:

Really..? For the money, and they’re $70 a piece?
Just get the $20 per bulk ones on aliexpress. I have 4 and they’re awesome.

 

[Dan B.]

Really..? For the money, and they’re $70 a piece?
Just get the $20 per bulk ones on aliexpress. I have 4 and they’re awesome.

I agree, they’re pricey. But as the more “premium” brands go they’re less expensive than some of them.
Some have had great luck with the Ali bulkheads, many have not, citing improperly machined bearing races and poor alignment of the pinion/crown gears (input bore drilled “crooked”) as the most common problems.
I guess that to a certain extent it’s a crapshoot no matter what, as people here have also told of problems with Treal units ($60.00) and a lot of complaints for the Hot Racing ones ($50ish in most places) too.
The price for the new Arrma 6s EXB aluminum diffs seems pretty absurd IMO, given the fact that most people go aftermarket because the stock ones take so many shims to get them right. Hopefully their aluminum ones are much better. I won’t ever know personally, because I’m not buying them.
I’ve had the best of luck with Vitavon and, more recently, Scorched RC, with much better oversized bearings.
I would never spend that kind of money on an off-road basher though.
I totally agree with the OP’s decision to stay with the stock plastic/nylon ones.

 

[332_RC]

I agree, they’re pricey. But as the more “premium” brands go they’re less expensive than some of them.
Some have had great luck with the Ali bulkheads, many have not, citing improperly machined bearing races and poor alignment of the pinion/crown gears (input bore drilled “crooked”) as the most common problems.
I guess that to a certain extent it’s a crapshoot no matter what, as people here have also told of problems with Treal units ($60.00) and a lot of complaints for the Hot Racing ones ($50ish in most places) too.
The price for the new Arrma 6s EXB aluminum diffs seems pretty absurd IMO, given the fact that most people go aftermarket because the stock ones take so many shims to get them right. Hopefully their aluminum ones are much better. I won’t ever know personally, because I’m not buying them.
I’ve had the best of luck with Vitavon and, more recently, Scorched RC, with much better oversized bearings.
I would never spend that kind of money on an off-road basher though.
I totally agree with the OP’s decision to stay with the stock plastic/nylon ones.

I just got my first set of aluminum bulkheads. Treal set. I built the diffs complete, & set them in the bulkheads- dry. Checked both diffs in both bulkheads & they are good. One is a little noisy. I think it's the input gear depth. I haven't bothered with shims yet- I may not. Lash is ok- one has a little more than the other. Otherwise they are beautifully machined & only one shim on the ring gear side on both diffs for no side to side play.