WR-02 Gearbox

[TexVan]

Years ago, I wanted to change the motor on my Wild Willy 2, but 2 of the screws holding the motor on are completely stripped.  I went to multiple hobby shops and they couldn't get them out.  I tried extractor screws...I feel like I tried everything, but I couldn't get those screws out -- I'm open to suggestions.  Ha ha.  And since I couldn't remove the screws, I couldn't take the gearbox apart either.

So recently, I decided I wanted to get the car running again, and I just want to get a new gearbox.  I've searched the net and can't find one.  I don't need the entire chassis, the wheels, or anything else...just the gearbox.  Is it possible to buy just the gearbox to a WR-02 chassis?

[JimBear]

@TexVan Yep, you can buy the whole kaboodle with motor, parts number 18085153. 

Or the gearbox housing, TA-10005713. 

[Guest]

1 hour ago, TexVan said:

Years ago, I wanted to change the motor on my Wild Willy 2, but 2 of the screws holding the motor on are completely stripped.  I went to multiple hobby shops and they couldn't get them out.  I tried extractor screws...I feel like I tried everything, but I couldn't get those screws out -- I'm open to suggestions.  Ha ha.  And since I couldn't remove the screws, I couldn't take the gearbox apart either.

So recently, I decided I wanted to get the car running again, and I just want to get a new gearbox.  I've searched the net and can't find one.  I don't need the entire chassis, the wheels, or anything else...just the gearbox.  Is it possible to buy just the gearbox to a WR-02 chassis?

Have you tried using a Dremel on the head of the screw? Just grind enough out so you can get a flat head screwdriver in there and extract it. 

[TexVan]

@JimBear Thanks!

 

@Gorgonzola  I don't own a Dremel tool, but it might be time to invest in one.  As for the stripped screws, its like a smooth concave divot.  There is little to no surface information for an extractor screw, or anything else to grab onto at this point.  I've never encountered a screw this stubborn.

[Guest]

30 minutes ago, TexVan said:

@JimBear Thanks!

 

@Gorgonzola  I don't own a Dremel tool, but it might be time to invest in one.  As for the stripped screws, its like a smooth concave divot.  There is little to no surface information for an extractor screw, or anything else to grab onto at this point.  I've never encountered a screw this stubborn.

Just buy a cheaper one buddy. I bought one of Ebay for 30 quid and it's superb. It lasted way longer than a genuine dremel. You might have to drill into what's left of the screw and try extracting it that way. Are they hex head screws? 

[TexVan]

@Gorgonzola  It's just a regular phillips head screw.

[Guest]

12 minutes ago, TexVan said:

@Gorgonzola  It's just a regular phillips head screw.

The drill and extract method might be your best option. There's bound to be some videos on YouTube showing how to do it. 

[Twinfan]

Given the fact you can buy a replacement gearbox for about £30 I don't think it's worth the bother of Dremels etc if you don't already have one!

I'd just buy a new 'box, then hack the old one's casing about to salvage a few spare parts for the future.

[Twinfan]

https://www.ebay.co.uk/itm/267026474463

[TexVan]

@Twinfan  Yeah, I don't think I'm going to run out and buy a Dremel set right away, but it is a versatile tool, and I have run into a few situations where having one would be handy.  For now, I may just order a new gearbox.  A Dremel would probably help cracking open the old one though.  Ha ha

[MadAnt]

Just drill the screw heads off and yank the motor out. Simple job, don't waste a whole gearbox.

[Thommo]

3mm screws only need a 3mm drill bit if you can centre it.  Might avoid the plastic completely with a steady hand.

[TexVan]

Like I said, I've tried drilling them out, several hobby shops have tried getting them out, I've tried extractors...they are really stuck in there.

[TexVan]

@MadAnt Here's what it looks like.  

[MadAnt]

5 hours ago, TexVan said:

@MadAnt Here's what it looks like.  

Drill it until the heads break off.

I have no clue how you messed this up unless you used the wrong type of driver or tools.

How do the rest of the gearbox screws look?

[TexVan]

2 minutes ago, MadAnt said:

Drill it until the heads break off.

I have no clue how you messed this up unless you used the wrong type of driver or tools.

How do the rest of the gearbox screws look?

Ha ha ha, I don't either.  The rest of the screws are perfectly fine.  

[RichieRich]

That is impressive. I don’t think I’ve ever seen that before. There must be thread lock involved because over tightening surely would have cracked the gearbox. 

[Juggular]

On 6/11/2025 at 12:44 AM, TexVan said:

Ha ha ha, I don't either.  The rest of the screws are perfectly fine.  

Probably a Phillips driver is to be blamed.  Tamiya uses Japanese Industrial Standard (JIS) screws. 

The inside valley of the Phillips driver is rounded and the tip is blunter.  JIS screw slots are narrower.  Old Phillips tend to jump out of the slots. 

Newer bits are "international."  Most of them are made in China and shipped to the US, Japan, and Europe.  I found that many are compatible with JIS screws.  But occasionally, people use the Phillips driver from 1980s, and end up grinding off the screwhead.  When the head is exposed, I cut a slot and use the flathead to undo.  But when it's recessed like that, drilling with a 3mm bit is the only solution.  The head comes off like a ring.  

 

I got below for $12. 

It can do 70% of the things a Dremel could. Since it's smaller, I found that it's easier to work with than a corded Dremel that I use for occasional woodworking.  

https://www.temu.com/electric-grinding-machine-with-handheld-small-jade-carving-small-electric-drill-micro-drill--with--accessories-and-storage-bags-portable-with--g-601099738445043.html?_oak_mp_inf=EPPpiYOn1ogBGiAyNGEyMGE0OGM3ODg0ZjgxOGZmODRlZWM0NDUyZjhmZSDp5ty7%2BjI%3D&top_gallery_url=https%3A%2F%2Fimg.kwcdn.com%2Fproduct%2Ffancy%2Fmarket%2F255f351b402101030e9b4a732a697b9a_JAlQnPAsmtgdO.jpeg&spec_gallery_id=1&refer_page_sn=10009&refer_source=0&freesia_scene=2&_oak_freesia_scene=2&_oak_rec_ext_1=MTMzMA&_oak_gallery_order=1490668998%2C247417981&search_key=handhend drill&refer_page_el_sn=200049&_x_sessn_id=rvcj6cydpa&refer_page_name=search_result&refer_page_id=10009_1750861297562_2syngdb5hj

It has 5 speeds.  At high speed, it made a short work of cutting the shaft of this 550 motor. 

 

[TexVan]

@Juggular Yeah, this was the first RC car that I ever bought many years ago.  I didn't have the best tools back then.

I've since ordered a new gearbox from my local hobby shop, and was able to pry open the old one with a little elbow grease and get all the parts out.  I can't wait to finally get this Wild Willy finished.

I'll have to check out that tool.  Looks like a real time saver!

[simensays]

On 6/10/2025 at 6:39 PM, TexVan said:

@JimBear Thanks!

 

@Gorgonzola  I don't own a Dremel tool, but it might be time to invest in one.  As for the stripped screws, its like a smooth concave divot.  There is little to no surface information for an extractor screw, or anything else to grab onto at this point.  I've never encountered a screw this stubborn.

No Dremel needed - you probably have an electrical drill? Use a 3mm metal (!) drill bit, carefully place it centred on the bolt head and drill it out (just the head, you'll know when to stop as the head part will lift/spin when you are thru). Use slow speed on your drill, it is more efficient when drilling metal and the bit won't get too hot and break. These bolts are small and fairly soft, so it won't be any harm on the tools. You can stop and check after a few seconds in order to get a visual reference of the progress and to ensure you in centre of the screw head. Normally I would start with a smaller drill bit (one or two sizes down) and change up to a size larger than the screw (i.e. on a stuck 5mm bolt I'd start with a 3mm bit to make the centred groove, and then use a 6mm bit for the last part of the procedure).

When both head are drilled out, simply remove the motor and use vice grips to remove the protruding threaded stumps stuck in the motor. Remember - a few drops of WD40 will be your friend (but I take it for granted that you've already applied this before even posting this issue).

EDIT, sorry didn't bother reading thru the whole thread for such a simple problem - but I see many others suggested tthe same. This is the correct and simple way to do it - however, if the bolt head spins when you try to drill it out - or even when you first started to screw it out, well then it is a different fun challenge. If the head don't move - drilling it out will work great.

 

 

[Dan1891]

How did you manage to spoil the screwheads that bad?

Even with the wrong screwdriver?

[TexVan]

On 8/3/2025 at 8:20 AM, Dan1891 said:

How did you manage to spoil the screwheads that bad?

Even with the wrong screwdriver?

I don't know.  It was a long, long time ago and I was inexperienced.  Ha ha.  However, that gearbox was pre-assembled by Tamiya, so they were tightened at the factory.  And those were the 2 screws holding the motor in place.  I didn't have a JIS screwdriver, but I still say those particular screws were not going to move no matter what.  Ha ha.  The rest of the screws on the car/gearbox were not a problem.

Anyway, I should be getting the new gearbox in a about a week or so.  It has taken forever.