Upgrade Mega/BLS plastic transmission to BLX metal

WoodiE

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So you've started with one of the Arrma MEGA or BLS models and now wanting to upgrade to a brushless and LiPo setup for longer runtimes and a much faster vehicle!?

Upgrading Arrma Transmission from plastic to BLX metal



Before doing so it's highly recommended you upgrade your plastic transmission to a metal transmission setup found in the Arrma BLX models as a brushless and LiPo setup is certainly going to put a lot of stress on your gearbox. Here is a list of the parts you're going to need to upgrade your Arrma gearbox to metal:

If you have an older model (before 2014) you'll also need the following parts, otherwise the newer Arrma models already come stock with the below parts:
  • AR310378 - Differential Gear Maintenance Set
  • AR310399 - Gear Differential Outdrive
 

LunchBox

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So you've started with one of the Arrma MEGA or BLS models and now wanting to upgrade to a brushless and LiPo setup for longer runtimes and a much faster vehicle!?

Before doing so it's highly recommended you upgrade your plastic transmission to a metal transmission setup found in the Arrma BLX models as a brushless and LiPo setup is certainly going to put a lot of stress on your gearbox. Here is a list of the parts you're going to need to upgrade your Arrma gearbox to metal:

If you have an older model (before 2014) you'll also need the following parts, otherwise the newer Arrma models already come stock with the below parts:
  • AR310378 - Differential Gear Maintenance Set
  • AR310399 - Gear Differential Outdrive
I'm going to need this with wanting to upgrade the sons granite
 

ajdragon

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Hi

Don't forget the 3 screws for mounting the motor mount to the tranny and 1 extra 3X12mm screw for the tranny case, there are 6 of them now.

AR722308 Flat Head Screw 3x8mm

AR725312 Button Head Cross Machine Screw 3x12mm
 

wheatjptb

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Ive ordered the parts to do this upgrade but I was wondering about the layshaft gear. I don't see it anywhere as far as an upgrade. Only the idler gear and diff. I bent my diff outdrive and stub axle on one side so I figured I would go ahead and upgrade the gears while Im at it.
 

BFH

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AR310016 would be the layshaft gear. They call it a 20 tooth idler for some reason.

2016-02-07%2020.02.54_zpsawwdkufe.png
 

Kregger

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Hey guys.

I don't know if anyone else has posted this somewhere but HPI part number 86944 (20 tooth Idler gear) drops right in. I was upgrading my Raider mega and decided that since I was putting in the Associated Ball diff in I would give it a try instead of trying to get my hands on the diff gear set.
I post pics when I get a chance.
 

WoodiE

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Hey guys.

I don't know if anyone else has posted this somewhere but HPI part number 86944 (20 tooth Idler gear) drops right in. I was upgrading my Raider mega and decided that since I was putting in the Associated Ball diff in I would give it a try instead of trying to get my hands on the diff gear set.
I post pics when I get a chance.
Thanks for sharing. Any reason why we'd want to use the HPI idler gear over the Arrma metal gear?
 

Kregger

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In my case, I didn't need the whole diff gear set (AR310416), I just needed the idler gear itself and the gear set seems to be on back order at some stores.
 

ajdragon

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Hi

Thank you for that tip! I'm also doing the Associated Ball diff installation. Here's a question for you, how did you get the bearings to fit properly. After getting the Associated Ball diff shimmed into place I noticed that only a small portion of the diff out drives sit inside the bearings on each side, maybe about a 1/16" into each bearing. As it is right now I am still trying to make some shims to move the bearing closer together.
 

YZFR1

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Some Granite BLX data to add in -- my "built fast...built tough" metal gear diff went out this past weekend -- just gentle street running, all on NiMH. Made the clicky clicky sound for bit, then stripped out completely. Unless there are new 2016 factory upgrades to the transmission, going to stock BLX spec does not seem like a good solution (my truck was purchased in December 2015). Will update once it gets back from warranty repair.
 

Kregger

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Hi

Thank you for that tip! I'm also doing the Associated Ball diff installation. Here's a question for you, how did you get the bearings to fit properly. After getting the Associated Ball diff shimmed into place I noticed that only a small portion of the diff out drives sit inside the bearings on each side, maybe about a 1/16" into each bearing. As it is right now I am still trying to make some shims to move the bearing closer together.
I never noticed the amount when I did my fury. The shims I used went right on the diff itself and didn't move the bearings toward the diff, I thinking of going to the hardware store to see if I can find a big enough shim to try your idea. I seem to be having trouble finding shims to go around the outdrives. My fury has been shimmed out with the diff for years without a problem, but I only race it with a 17.5 motor.
 

wheatjptb

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Good info guys. Thanks. One more question. Ive got the gear box back together and in the truck. Motor mount is on and everything is good. Except one thing. Is there any way to put the motor gaurd back on? The gear box off of the bls is one whole piece, gear box, motor mount and all the way around the motor for protection. What in the world am I missing? Im guessing its an obvious answer that I just don't see.

Or did I not buy a piece I need? That would be my luck.

Ok. I see what I need. The blx has all those parts separate. No big deal. I ordered motor guard and it should be here next week.
YZFR1- hate to hear that. I love these trucks but they do have a few issues I wish Arrma would take care of. If these few problems aren't resolved, they will never become the brand they could and should be.
 

uberfinity

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Is it recommended to change over to the 32 pitch gears, or just stick with the 48?
 

BFH

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Is it recommended to change over to the 32 pitch gears, or just stick with the 48?
I've been running the 48p gears pretty hard with a mod motor with no issues. I'm only on 2s though.
 

Sethy89

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So you've started with one of the Arrma MEGA or BLS models and now wanting to upgrade to a brushless and LiPo setup for longer runtimes and a much faster vehicle!?

Upgrading Arrma Transmission from plastic to BLX metal



Before doing so it's highly recommended you upgrade your plastic transmission to a metal transmission setup found in the Arrma BLX models as a brushless and LiPo setup is certainly going to put a lot of stress on your gearbox. Here is a list of the parts you're going to need to upgrade your Arrma gearbox to metal:

If you have an older model (before 2014) you'll also need the following parts, otherwise the newer Arrma models already come stock with the below parts:
  • AR310378 - Differential Gear Maintenance Set
  • AR310399 - Gear Differential Outdrive



What about the spur what spur and pinion should i use with my BLX 2s lipo?
 

ajdragon

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Hi

That's a good question the BLX input shaft is 1.5mm shorter then the Mega input shaft. What we need is a side by side comparison.
 
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