MITCH316 ERBE rebuild

[MITCH316]

I stripped the thread in my RPM A-Arms a while back from cart wheeling my truck. I tried super glue, blue loctite and red loctite with no luck. I had great success in the past using the above methods on stock A-Arms but this time round no luck.

After a few short runs my camber and toe angle would be all over the place this was driving me crazy as my truck would be all over place making it hard to steer and control.

What I ended up doing was using some M5 threaded inserts.


Category: Inserts - Expansion

Material : Brass.

Easiest inserts to install - simply push into a pre-moulded hole.

Used with plastics or other materials. Material must be strong enough to withstand the expansion of the insert.

The insertion of the screw locks the external knurls into the wall of the hole.

Provides excellent thread durability but where maximum strength is required other inserts shown in this catalogue should be preferred.

Thread Size:: M 5.0 x 0.8
A±0.1 :: 6.65
L±0.25:: 9.52
Recommended Hole Diameter (mm):: 6.35 (0.2500 inch)



And the finished result...a very quick and easy install. I am yet to test this to see how well it works and will use blue loctite to to lock my camber into place.

[MITCH316]

This is the new Hot Racing diff cup.

Below is a pic of the old diff cup (the black on the left) compared to the new one (the blue on the right).



The new screws are longer than what came with the old HR diff and they have replaced the countersunk screw head with the BHC screw which is used on the stock diff cups.



Hers is a comparison of the internal of the 2 cups...as you can see the new one (blue) resembles a stock cup. As you can see they have reworked the mould for the internals of the cup.



What is nice about the new HR diff cups is that there is NO MODS necessary to fit the I-bar into the cup. As seen below it is a direct drop of the the spider gear system into the diff cup.



Hot Racing Aluminum Differential Case for the Traxxas Revo trucks. (in place of Traxxas 3978) This differential case features a 6061-T6 aluminum body

FEATURES:
CNC Aluminum Construction diff case

YOU WILL RECEIVE:
(1) blue Aluminum Differential Case
(4) screws

REQUIREMENTS:
Steel axial guide and gasket that comes with the plastic diff case
Stock Gasket from (TRA3978)
Installing gear set and attaching to bevel gear
Thread locking adhesive to keep screws from loosening due to vibration.

SPECIFICATIONS:
Out drive plate length: 9.5mm
Diameter 24.3mm
Diff. Case
Length: 14.0mm
Diameter: 25.5mm

NOTE:
This replace TRA3978 make to work with TRA5382X diff gear set. Do not over tighten Use only Silicone diff lube

[JustinThyme]

Nice to see HR caught on. I just sent a set back not a month ago because of the Ibar cross carrier support not fitting and used FLM cups for the slash 4xr4 where the fit! One thing I really like is the new HR fits the end cross carrier pin supports. About time someone did this. Figures after I just built a slew of diffs with the FLM cups!

[MITCH316]

Not much to add...replaced rear ring and pinion gear this weekend; went out for a burn and can still hear the classic stripped diff sound when the truck is burning it on rough terrain. It may be the front one need replacing too.

I think I am going to tear my eRevo down and rebuild it with a major service. I am in no rush to do this as I have been having so much fun with my eSlayer pro 4x4.

[Foxprogt]

craig

I look forward to seeing how them new HR diff cups hold up. I havent ran my truck to hard yet but so far my diff are holding up. I anticipate my diff cups to suffer the same wear and tear as yours and some others have so id like to build me a spare set of diffs ready to go in. I would hope that 100% dedicated e-revo diff cups wont wear down like the old HR cups did. Would have been nice if they made them with the stronger aluminum but let us know how they work out for ya.

[hottrodd1090]

This is the new Hot Racing diff cup.

Below is a pic of the old diff cup (the black on the left) compared to the new one (the blue on the right).



The new screws are longer than what came with the old HR diff and they have replaced the countersunk screw head with the BHC screw which is used on the stock diff cups.



Hers is a comparison of the internal of the 2 cups...as you can see the new one (blue) resembles a stock cup. As you can see they have reworked the mould for the internals of the cup.



What is nice about the new HR diff cups is that there is NO MODS necessary to fit the I-bar into the cup. As seen below it is a direct drop of the the spider gear system into the diff cup.



Hot Racing Aluminum Differential Case for the Traxxas Revo trucks. (in place of Traxxas 3978) This differential case features a 6061-T6 aluminum body

FEATURES:
CNC Aluminum Construction diff case

YOU WILL RECEIVE:
(1) blue Aluminum Differential Case
(4) screws

REQUIREMENTS:
Steel axial guide and gasket that comes with the plastic diff case
Stock Gasket from (TRA3978)
Installing gear set and attaching to bevel gear
Thread locking adhesive to keep screws from loosening due to vibration.

SPECIFICATIONS:
Out drive plate length: 9.5mm
Diameter 24.3mm
Diff. Case
Length: 14.0mm
Diameter: 25.5mm

NOTE:
This replace TRA3978 make to work with TRA5382X diff gear set. Do not over tighten Use only Silicone diff lube

what is the part number for "the steel axial guide plate and gasket"

[MITCH316]

craig

I look forward to seeing how them new HR diff cups hold up. I havent ran my truck to hard yet but so far my diff are holding up. I anticipate my diff cups to suffer the same wear and tear as yours and some others have so id like to build me a spare set of diffs ready to go in. I would hope that 100% dedicated e-revo diff cups wont wear down like the old HR cups did. Would have been nice if they made them with the stronger aluminum but let us know how they work out for ya.

I will do mate...I am actually going to use them in my new build I am busy with and will probably change my eSlayers out to these. Both of these trucks will be running 4s...my new street build may run 6s at times.

I will give feedback on these new HR diff cups...hopefully wear and tear is not too bad.

I seem to be having issues with my LST2 diffs in my eRevo again...I am going to ride them till they break and then strip my truck down and rebuild it .

[hottrodd1090]

do they mean to say axle? that is what i am assuming.does anyone know if i can just buy the gasket for the diff cup without buying everything else it comes with?

[MITCH316]

what is the part number for "the steel axial guide plate and gasket"

do they mean to say axle? that is what i am assuming.does anyone know if i can just buy the gasket for the diff cup without buying everything else it comes with?

G'day mate...are you referring to this part...TRA3978 Traxxas Carrier Differential Heavy Duty, you would reuse all the parts and except for the stock plastic diff cup if using the new HR diff cup RVO11X06.

They do look good...I cant wait to use this in my new build, I am still waiting for bits and pieces to come in.

EDIT: I think the steel axial is referring to the spider gears shaft.

[hottrodd1090]

i oredered 4 cups and 2 strc diff housings and can someone please tell me what shims i need to order so when i put these together they can be the best they can be and see how long they hold up on 4s.i figured out what part numbers they were talking about but if you read it,it sounds like you need to buy something from axial or atleast thats how i read it til i figured out they ment axle

[MITCH316]

You would need 6mm, 8mm and 10mm bearing shims to shim the diff.

6mm bearing shim Calandra #4736

8mm bearing shim Calandra #4738

10mm bearing shim Calandra #4740

[hottrodd1090]

hey thanks alot do the shims go behind the bearings like for the pinion gear or on the pinion gear then slide gear in or do you have the link to the shim mod i cant seem to find it

[hottrodd1090]

EDIT: I think the steel axial is referring to the spider gears shaft. yeah i figured that out but it sounds like its parts from axial not parts for the axle and its talking about the ends too

[MITCH316]

hey thanks alot do the shims go behind the bearings like for the pinion gear or on the pinion gear then slide gear in or do you have the link to the shim mod i cant seem to find it

No worries mate...post #319 will help you out. Scroll up and you can see the diff been put together.

EDIT: I think the steel axial is referring to the spider gears shaft. yeah i figured that out but it sounds like its parts from axial not parts for the axle and its talking about the ends too

Yip, they are talking about the spider gears shaft and steel plates on the end.

[hottrodd1090]

hey thanks a lot i was wondering if i was doing it right.so i guess i need to put it all together dry and test fit everything shim it then add 100 diff fluid then before adding grease to the ring and pinion test fit that then add grease

[MITCH316]

Yeah mate...make sure you tighten the diff case fully and not just with your hand to see if shimmed correctly...once your happy with you're shimming add lube to the diff cup and grease the ring gear. It can be a time consuming and frustrating in the beginning opening and closing the diff case but does get easier with practice.

Good luck with it mate ...take your time while doing it.

[hottrodd1090]

thanks for the advice.should i break them in first or just make them slightly tight?

[MITCH316]

The way I check my diff is I grab each CVD output between my thumb and index finger with the pinion gear facing towards me. I then flick the diff with my free fingers so the diff rotates between my hands while holding the CVD output between each thumb and index finger.

If shimmed correctly the diff should spin freely with no binding, it may bind in one spot when rotated but if binding is to tight and the diff wont rotate freely then the diff is shimmed to tight.

I break my diffs in by taking it easy for a couple runs before hammering my truck.

I hope the above explanation makes sense mate.

[hottrodd1090]

oh it makes alot of sense to me.i'll do my best thank you.a friend and i were talking today about hardening my ring gear.he's not into the hobby but we were both into hoping up cars.we think if i take a torch and heat up the ring gear then dip it into cold water a few times it should harden the gear and make it stronger.we are basing this off real gears out of hot rods.i noticed that the pinion gear seems to already be hardened so i am going to try the ring gear.if it works great and if it doesn't then i've atleast tried it.

[MITCH316]

Cheers mate...I'm glad I could help. Let us know how your hardening of the gears work out for...good luck with it.

[hottrodd1090]

thanks and whats your thinking on my idea? i just got my strc outer diff cases and the hr cups will be here tomorrow and just waiting on shims now tracking says be here on monday

[MITCH316]

I was thinking of doing that myself a while back to see if it would work...I gave up on that idea once I saw revoroller do the Losi mod. Good luck with it mate and the diff rebuild.

[hottrodd1090]

cool thanks yeah i did my 1/8 scale diffs too right after him.but i have built 3 now working on 4th and 2 are for my grandsons so i dont want to go threw all the grinding and stuff just want to be able to grab parts of the shelf and rebuild.but if i can spend a few extra bucks and make them almost bulletproof then i'll go that route like the outer diff case and hr diff cups.they both take all stock parts that i like just open up and replace parts if they break

[MITCH316]

This is from post #20...my external BEC and ESC.

I removed the external BEC from my truck late November and bumped up my ESC's BEC to 6V with the castle field link programmer. So far no issues, my truck is running 100%. I may look at installing the external BEC again when I rebuild my truck and run my servo straight off the external BEC at 7.4V.

At the moment my servo is performing just fine of the MM ESC.

[MITCH316]

This is read in conjunction with post #17.

I was doing a little bit of maintenance work on my truck and noticed this. My retainer rings on the front axle carriers (knuckles) had bent out of shape.

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A close up view.

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I used a long nose pliers and tried to make the retainer ring round again rotating the ring 90° as well.


It's not perfect but a big improvement from before.

[mydudrevo]

you said you were having diff issues what did it end up being just need reshimming

[MITCH316]

you said you were having diff issues what did it end up being just need reshimming

Not sure mate...I think its wear and tear on the front diff, I have re-shimmed at the moment so its better. Its only noisy on some landings now.

Other than that my eRevo is still going strong and a lot of fun to bash around .

[mydudrevo]

good to hear mines going strong as well just need so shims to shim my lst driveshafts to be back running again drove it yesterday but i dont like the amount of play it has between the hex and the carrier bearing but ill update my thread once i get that done

[buduck04]

Hey Mitch Do you know if you can use the hot racing progressive rockers with this sway bar kit ... Not sure if you can since you had to drill into the bottom of your rockers

[MITCH316]

Hey Mitch Do you know if you can use the hot racing progressive rockers with this sway bar kit ... Not sure if you can since you had to drill into the bottom of your rockers

Yeah it will...have a look at 50togos thread post #369.

[MITCH316]

These are the shims I am using now using to shim my diffs and anywhere else on my rigs that need shims...these are from 3 racing; what''s nice about these shims are that they come in 3 different thicknesses (0.1, 0.2 & 0.3).

6mm Shim Spacer 0.1/0.2/0.3mm Thickness 10pcs Each - 3Racing 3RAC-SW06
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8mm Shim Spacer 0.1/0.2/0.3mm Thickness 10pcs Each - 3Racing 3RAC-SW08
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10mm Shim Spacer 0.1/0.2/0.3mm Thickness 10pcs Each - 3Racing 3RAC-SW10
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12mm Shim Spacer 0.1/0.2/0.3m Thickness 10pcs Each - 3Racing 3RAC-SW12
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[WesleyK]

Thanks for the heads up! Just ordered them, already had 6mm shims on the way, but now i also have 8mm and 10mm shims on the way . By the way, where do the 8mm shims go?

[MITCH316]

They go on the ring gear side of the diff mate...the 12mm shims shown are for my Rally's rear pinion.

I too have done the Losi mod to my rig as I got sick of working on my diffs just about every time I used my truck. I am a 2/3s basher mate...I no longer try to use my eRevo as an all rounder and is now purely a basher...instead I have built a rig for all surface I run on...what can I say, I am an RC addict.

Info on the losi diff and shimming...need to scroll through a bit
http://traxxas.com/forums/showthread...=1#post5279024

Info on stock diff shimming
http://traxxas.com/forums/showthread...-rebuild/page8

You can have a read through the whole thread if you like, there maybe some info that would be of some use to you . There are a lot of pics, references and my hopups are backed by videos so you get an idea of exactly what I am doing with my truck.

[NewbieToTraxxas]

Wow Great read! Thanks so much for all the info! I just ordered my erbe! I can't wait to use this resource!!!!

[MITCH316]

No worries mate...you're welcome. I'm still bashing my beast around having a blast, this truck gives me a lot of joy .

[sipho banda]

Hello Mr Mitch. I only recent find this thread and go through it. Very nice, very nice. You will not be planning hopefully an EMaxx Brushless Build please so I can follow that. I like when useful info inside and nothing as detailed as yours there. Only postman postman all the time. Thanks.

[MITCH316]

Hello Mr Mitch. I only recent find this thread and go through it. Very nice, very nice. You will not be planning hopefully an EMaxx Brushless Build please so I can follow that. I like when useful info inside and nothing as detailed as yours there. Only postman postman all the time. Thanks.

G'day mate...thanks for the feedback, I've tried to keep my thread as informative as possible. I assume you are talking about people referring to the mail man in their threads?

I have been toying with the idea of building myself an eMaxx with an FLM chassis and 1/8 hybrid diffs...that may be a project for next year some time. I rather do enjoy building custom rigs.

[MITCH316]

Well, I was out having a blast with my truck doing some grass runs and this happened.
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I have managed to rip the pivot ball from the front left A-Arm. I have gone and fixed this again with brass threaded inserts.

I put this here for reference again. What I ended up doing was using some M5 threaded inserts.
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Thread Size:: M 5.0 x 0.8
A±0.1 :: 6.65
L±0.25:: 9.52
Recommended Hole Diameter (mm):: 6.35 (0.2500 inch)
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And the finished result...a very quick and easy install. I installed these to my rear A-Arm about a month and half back and have had good results so far with the inserts staying in place.

Basically my front and rear A-Arms have these brass inserts fitted now due to the pivot balls been ripped out..
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[Naaier]

Another great tip...thanks MITCH316. I have just recently done this too from your previous post when you did the rear A-Arms. Works like a charm .

[WesleyK]

It also looks very tough, will do mine too, when they start to pop out.
Do you drill the holes to 6.35mm? Or just leave them as they are?