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KidsWheels
Need new motors? Grind a gearbox? Adding teeth to a pinion?
User avatar
By bruces_eviltwin
#99899
i have the 21 22 23 box running a 22t on 18volts and have had no issues so far
User avatar
By taz11
#99906
Great! Thanks of the update.

My 16t is also still running without issue.
User avatar
By taz11
#104104
landon wrote:Quick question to the pros... are all #7R gearboxes made for 1/2" axles?



Two sizes...7/16 and 3/4. They are typically sloppy.
By salazarjohn
#108451
hey guys burnt out a motor on a dune racer and need some help. I've looked at the 7R gearbox. I see the dimples but they seem to be between the 15-16-17 and the 18-19-20.

Being that the factory pinion is a 15t I'm guessing an aftermarket pinion would be the 16t?
Last edited by salazarjohn on Wed Sep 18, 2013 11:02 pm, edited 1 time in total.
User avatar
By taz11
#108469
salazarjohn wrote:hey guys burnt out a motor on a dune racer and need some help. I've looked at the 7R gearbox. I see the dimples but they seem to be between the 15-16-17 and the 18-19-20.

Being that the factory pinion is a 15t I'm guessing an aftermarket pinion would be the 16t?



Correct
By JimmyPGE
#114771
Hey all, new here, finally figured it how to join the forum from my phone, kind of a pain to disable the mobile version of the forum from a phone. Anyhow I recently got into modifying power wheels after I bought my 4 year old son an Orange Boss Mustang. What I've learned about the 7R gearboxes:

I've run a 21-22-23 box, with a HPI GT 550 motor and a 21T Traxxas gear successfully.
I've run a 15-16-17 box, with a HPI GT 550 motor and a 15T Traxxas gear successfully.
I've run a 18-19-20 box, with a HPI GT 550 motor and a 19T Traxxas gear successfully.
I've run the same 21-22-23 box that had 21T Traxxas gears with the new stock corvette 23T motors successfully.

I couldn't find any conclusive info confirming that you could run any gear between the range listed, just figured I'd post to share what I've learned sorry if it's already been posted.
User avatar
By toycrusher
#132956
Have to ask.

Has anyone tried swapping out the last two gears (wheel driver and one that contacts it) into a #7 box?
User avatar
By taz11
#132958
You can swap in the last gear but you have to trim the case. The pilot that the last gear rotates on is longer in the #7. Trim it to the length of the 7R pilot and it will work. If you don't trim it, it may still work, but has a tendency to bind.
User avatar
By toycrusher
#132960
taz11 wrote:You can swap in the last gear but you have to trim the case. The pilot that the last gear rotates on is longer in the #7. Trim it to the length of the 7R pilot and it will work. If you don't trim it, it may still work, but has a tendency to bind.


:? Trim the 7r wheel driver to fit in the #7 box? I destroyed 3 #7 boxes in about 120 seconds of run time in a hurricane and looking for a slightly more durable solution :roll: :x
User avatar
By taz11
#132964
toycrusher wrote:
taz11 wrote:You can swap in the last gear but you have to trim the case. The pilot that the last gear rotates on is longer in the #7. Trim it to the length of the 7R pilot and it will work. If you don't trim it, it may still work, but has a tendency to bind.


:? Trim the 7r wheel driver to fit in the #7 box? I destroyed 3 #7 boxes in about 120 seconds of run time in a hurricane and looking for a slightly more durable solution :roll: :x



Noooooo.....


Trim the #7 box to fit the 7R driver.
User avatar
By toycrusher
#132967
taz11 wrote:
toycrusher wrote:
taz11 wrote:You can swap in the last gear but you have to trim the case. The pilot that the last gear rotates on is longer in the #7. Trim it to the length of the 7R pilot and it will work. If you don't trim it, it may still work, but has a tendency to bind.


:? Trim the 7r wheel driver to fit in the #7 box? I destroyed 3 #7 boxes in about 120 seconds of run time in a hurricane and looking for a slightly more durable solution :roll: :x



Noooooo.....


Trim the #7 box to fit the 7R driver.


AAAhhhhhhhhhh! :geek:

Now the million dollar question... do you have any 7r pieces?
User avatar
By taz11
#132968
....and he asks the person who still needs to get back on 27 other pending parts :roll: :roll:


Yes. I'll pm you later so we don't clog up this thread.
Last edited by taz11 on Tue Jun 16, 2015 8:21 am, edited 1 time in total.
#133516
I've done an extensive mod to my kids Hurricane including running the battery radio off a USB cord with a USB RF Radio to play MP3's so I am pretty good with trial and error. I found today 2 broken teeth on the #7 snap together drive gear and I am looking at an inner rim that is quite scuffed up from it slipping. The question I REALLY want to know is, Why is this not a permanent attachment? What is the purpose of the teeth? AKA: I would like to take some heavy duty caulk/construction glue and basically weld the #4 broken gear to the rear tire that is stripped out. Looks like it was only done this way to fit in the shipping box to a store. So, has anyone done this? do these teeth move somehow and come in and out of the tire when shifting? Pros? Cons?
User avatar
By toycrusher
#133531
give it a try, you have nothing to lose at this point, the inner wheel needs to be replaced as does the gearbox driver.
User avatar
By toycrusher
#133559
M.L.Toys wrote:If you weld the wheel to the gearbox you'll never be able to take the gearbox apart or the motor out.


That's true on most rides but the hurricane you will be ok
User avatar
By M.L.Toys
#133561
toycrusher wrote:
M.L.Toys wrote:If you weld the wheel to the gearbox you'll never be able to take the gearbox apart or the motor out.


That's true on most rides but the hurricane you will be ok


I'm not seeing how. Yes you can remove the assembly from the vehicle. But you won't be able to access the motor or gearbox screws. Unless you have a really long screwdriver and the screws all line up with the holes in the rim.
User avatar
By toycrusher
#133563
M.L.Toys wrote:
toycrusher wrote:
M.L.Toys wrote:If you weld the wheel to the gearbox you'll never be able to take the gearbox apart or the motor out.


That's true on most rides but the hurricane you will be ok


I'm not seeing how. Yes you can remove the assembly from the vehicle. But you won't be able to access the motor or gearbox screws. Unless you have a really long screwdriver and the screws all line up with the holes in the rim.


I get what you are saying and that would be correct, motor removal would be pretty impossible. I'm assuming that if it broke again he would be upgrading complete gearboxes anyway. It's definitely something to keep in mind.
#133781
Thanks for the support. Seeing the rim is stripped and needs to be replaced as it is, and the motor attaches to the jeep separately I would use a hacksaw to remove the #7 if I needed to separate it in the future and replace the #7 or full assembly and wheel hub. I was hoping someone has done this already and either failed or succeeded! The Wheel and Motor came off when I pulled the axle out So that is why I was trying to figure out why it wasn't all one piece to start.
By akallenberg
#135033
JimmyPGE wrote:Hey all, new here, finally figured it how to join the forum from my phone, kind of a pain to disable the mobile version of the forum from a phone. Anyhow I recently got into modifying power wheels after I bought my 4 year old son an Orange Boss Mustang. What I've learned about the 7R gearboxes:

I've run a 21-22-23 box, with a HPI GT 550 motor and a 21T Traxxas gear successfully.
I've run a 15-16-17 box, with a HPI GT 550 motor and a 15T Traxxas gear successfully.
I've run a 18-19-20 box, with a HPI GT 550 motor and a 19T Traxxas gear successfully.
I've run the same 21-22-23 box that had 21T Traxxas gears with the new stock corvette 23T motors successfully.

I couldn't find any conclusive info confirming that you could run any gear between the range listed, just figured I'd post to share what I've learned sorry if it's already been posted.


I have an orange boss mustang and I am currently running a 23T in a 21-22-23 box on 18 volts. I am going through the small gears and the gearboxes like they are both out of style, probably because I am using this on my grass with some small hills. Also, I have melted some wires. I am going to try the 18-19-20 box with a 19T pinion in the hopes that causes less stress on the gears, gearbox and electrical system. Also, I am planning on putting a steel first gear in the gear box. How did the boss run on the 19Ts? I also have the 15-16-17 gearbox, I would just need to order new pinions. How did it run in the 15T? Did you try 17T?
User avatar
By taz11
#135034
Are you using the factory 23t pinion or an aftermarket pinion?

I'd be leery of the steel gear. It will solve a breakage issue, but it will actually wear faster. Nylon is self lubricating. Steel is not and requires specific lubrication to survive. Its kinda like running you street car with grease in the transmission :o
Last edited by taz11 on Thu Sep 10, 2015 1:19 pm, edited 2 times in total.
By wirewalker25
#142161
I have an f150 with the 16t pinion, and the mltoys steel first gear. Can I run a 17t pinion without destroying either one? I have am also running 24v with a motor contoller and the heavier duty but apparently slower 775 motors. He wants more speed but also needs the additional torque for him and his buddy riding around our "not flat" yard. I have learned a lot from this site and everyone in it but the gearing ratios to achieve more speed is a bit overwhelming.
User avatar
By wired
#142175
#7 or 7r gearbox? Either way if you change just the pinion gear you will cause binding and damage.
User avatar
By toycrusher
#142228
wirewalker25 wrote:are there any gear changes that can be done or do I have to go back down to the 550 motors?


You can definitely run the 775 motors. To help you we need to know if you have #7 boxes or #7r
User avatar
By Hobby dad
#145770
Hello, I recently upgraded my sons power wheels escalade from 12v to 24v but I ground the teeth off the first gear in the gearbox and I was wondering if someone could help me figure out how I can replace all the gears from plastic to metal?? And where could I buy them? And how would I know what sizes to buy? And if I need to get a new pinion even if as of now my motors are working fine? Thanks a lot for any help
User avatar
By wesleyb82
#145773
Did you make any changes to the factory gearbox setup before this failure like new motors and pinions?
User avatar
By jmuether
#146438
I am so lost! I dont have a friggin clue what gearbox I have. It is a 00968-Q502-02 gear box in a KFX 4 wheeler with a 23 tooth pinion. I converted it to 18v and installed traxass 775 motors. Well like everyone else I ruined the drive gear or 1st gear in the gearbox. I ordered new gearboxes hoping i was ordering the correct ones from ml toys but received 00968-Q502-03 gearboxes which are the wrong ones, totally my fault. Im working with them now trying to get the correct ones. What I'd really love is to replace the burnt gear with a steel gear but like I said earlier I'm friggin clueless. Did tons of reading on here and other places and uuuggghhhh. So now I'm probably stuck with two gearboxes I can't use. Any help greatly appreciated.
Last edited by jmuether on Mon Jul 17, 2017 7:44 am, edited 1 time in total.
User avatar
By wesleyb82
#146442
A gearbox with a 23t pinion would be a 21-22-23 7R which will accept a 22t aftermarket pinion. If you are looking to replace the entire gearbox than you can use this gearbox: http://www.mltoys.com/Power-Wheels-Must ... 8-2821.htm. Or if you have just broken a gear you can use the same gear (1st,2nd,3rd,final) from any other 7R gearbox to replace it. Don't get lost in the part numbers, there are 3 7R gearboxes, 15-16-17, 18-19-20, 21-22-23. You can interchange any gear from any 7R to fix a broken gear but you must match the motor pinion with the gearbox. For example you can't put a 22t pinion in a 16t gearbox.

Regarding the first metal gear it is my experience that I have never broken the first gear. Here is a recent comment from the MPW facebook group which might be helpful

" From my experience and observations it seems to me there are two forces entering the gearbox, one from the motor, the other from the wheels. I use 300w 1,300mNm stall 775 motors with an 1kw ESC and overload it to 250+ lbs and have never broken any gear on a 55+ amp hard [ESC] launch. In other words, I have torture tested stock gearboxes and have never broken any gear on flat ground, especially not one on the motor side of the gearbox. Regarding the other force introduced from the wheels, I have noticed gears break [for us] over major changes in terrain on our property. There is a short but steep valley at the bottom of which we broke two of the larger gears, a drop off at the driveway which has broken a [middle] gear and a section that has ruts which has also caused breakage. We have not broken a gear on any flat portions of the lawn. This has lead me to conclude that significant changes in momentum transferred through the wheels into the gearbox (which can be relatively large considered cars can be traveling around 10mph while carrying 100+ lbs) are much more likely to break gears than forces introduced by the strongest 775 motors, using the strongest batteries (lipos) using a 1,000w controller which can peak at 55 amps throughput. Also, in my 5+ years of breaking cars, I have only damaged one [first] gear on the motor end of the gearbox which melted on the post while using HPI 550 motors (very fast motors). Once this gear was replaced and no other changes were made for some reason the replacement gear never failed under the same circumstances"
User avatar
By M.L.Toys
#146452
The number your reading on the side of the gearbox is an internal number Mattel uses and has nothing to do with being a part identifier. What is important is the dot that sits directly opposite the first gear shaft. It has a line pointing to it that leads to 3 numbers. Yours should point to 21,22,23.
User avatar
By jmuether
#146454
The gear that is toast is the gear that the motors pinion gear engages. Where would I buy that gear from? My yard has numerous inclines/declines all are pretty gradual .
User avatar
By wesleyb82
#146491
Is the gear loose on the post? If so the center might have melted on the post which changed the tooth engagement. Is the gearbox dry or is there grease on the post?

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