Vintage Three Speed Full Ball Bearing Install

[spankrjs 80]

There are some great tutorials on the web on rebuilding the vintage 3 speed transmissions:

http://www.robobugs.net/wordpress/wp-content/files/Tamiya_Bruiser_TrannySvcManual.pdf

 

This guy's rebuild manual is excellent, and he provides some great pictures, AND he does show swapping out some of the center bushings, but reinstalls bushings:

http://tamiya101.com/article_tamiya_bruiser_transmission.asp

http://tamiya101.com/bruiser_transmission_manual.pdf

 

I bought this Mountaineer back in 2014:

https://www.tamiyaclub.com/showroom_model.asp?cid=123664&id=123664

Using a spare transmission, I changed out ALL of the bushings for ball bearings. I had a detailed thread/pictures/"how to" on the Scale4x4.org site, but the site is gone, so the information is no more.

I did this almost 8 years ago, so my memory is a little foggy on all the details. It is risky, not a simple operation, but not brain surgery either.

Use at your own risk. The transmission does operate perfectly, BUT I have hardly drove this Mountaineer since performing this operation. I am finally about 99% complete with this Mountaineer project, so I need to test it out.

The following is not a 100% step by step, but I will hit the highlights.

A disassembled Bruiser/Mountaineer 3 speed (the easy parts):

 

We will be concentrating on items in the lower left corner of the picture: the large center section of the transmission and the rear output shaft. You could probably install a bearing on the front drive counter gear (also pictured by the two above mentioned parts), but I never did. It rides on a plastic bushing, supported by a threaded female shaft (as pictured).

The "easy" to swap out bushings:

 

[spankrjs 80]

The part below is what I refer to as the "rear output shaft". One end of this shaft sticks out the back of the transmission, it has a "flat" where the rear driveshaft attaches to it.

The "grey gear" rides on two flanged bushings. It is surrounded by the two pressed on "gold gears". NOTE the "real" splines on the right side of the shaft. Also note the "raised ridge splines" to the center of the shaft. One gold gear rides on full splines, the other on these "raised ridges".

To remove the gold gears, I simply used a flat screw driver and gently pried against the center grey gear, forcing them off. Be careful not to damage the teeth on the center gear. If I remember correctly it did not take a lot of force to do this.

[spankrjs 80]

To remove the center shaft from the transmission case, I put it "front side down" on a vice, used a small punch and hammer, and gently drove the shaft out the front side. This removes the gold gear:

I then slipped the three bushings/grey gear over the 'raised ridge splines" on the left hand side of the shaft (left in the picture above).

Leave this gold center gear alone, no reason to remove it.

 

Now, the tricky part. Ball bearings will NOT slide over these "raised ridge" splines. So, I chucked the shaft up in a hand drill and spun the shaft against a flat file to "remove" the ridges:

I did this slowly. Only removing enough of these "ridges" to slip the ball bearings over them.

[spankrjs 80]

Reassembling the center shaft. I used a shim between the two bearings.

 

A note on shims - compare the existing bushings to your new bearings. A thin shim might be needed to make up for the fact that the flange on the flanged ball bearing is thinner then the flange on the original bronze bushing. You will have to make this call. You are not trying to shim these parts super tight, just replicating how it was assembled. It would probably be wise to use a caliper and take some notes BEFORE pulling everything apart!!

Since I filed the "raised ridges" down, I needed to "recreate" them. After installing the ball bearings, I put the shaft on a steel vice, used a small flat screw driver that was the same size/length as the original "ridges", and "restruck" the ridges. Basically, the shaft is kind of soft, so you can strike it, and raise back up the "ridges".

Even though I "recreated" the rides, they were not as high as before.

So, I glued the "press" gears back in place with this:

This is super strong, way stronger then red "Lock-Tite". No way the press gears should come off!!!! BUT, use caution. This stuff sets up fast, AND, you do not want it running into your ball bearings because it will seize them up!!!!!!!!!!! So, be careful, maybe just use red gel Lock-Tite??

Picture of my "re-struck" ridge splines:

[spankrjs 80]

Install center shaft into case from the front side:

Place gold gear on shaft, carefully drive it back on (don't get sleeve retainer inside ball bearing!!!!!!!):

The reassembled rear output shaft:

And I ended up using this grease as lube on the gears. Since all the shafts now spin on ball bearings, no reason to use a liquid lube which would wick between the shafts/bushings:

And the transmission functions just fine.

I still need to do some long term durability testing, BUT that sleeve retainer stuff is very strong, AND I still have the little "raised ridge" splines to help hold the press gears in place. I am fairly confident in saying that something in one of the axles will fail way before something in the transmission!! And besides, these transmissions do use a slipper clutch (well, the Bruiser/Mountaineer).

I am sure the ball bearings will aid in the smoothness of operation/longevity of the gears. My only concern will be disassembly in the future due to the sleeve retainer. Heating the shaft with a torch (jewelers tip!!!) should aid in removal, if ever necessary? Since these ball bearings are way deep inside the transmission I do not really see how they could be contaminated (unless you submarine the transmission often). So, maybe installing high quality ball bearings will result in a "lifetime" fix??

Anyway, just some information/pictures. Use at your own risk!!!

[steponit! 23]

Wow! That is some really cool info, spankrjs !! Thank you very, very much for sharing !! Really appreciate it !!

[SuperChamp82 760]

Super thread @spankrjs

Thank you 😊 

 

[spankrjs 80]

No problem guys, glad you found it interesting, thank you 

[Cambodian Tire 0]

Wow great info, thanks spank!

 I just found a device that I could still log into as I haven't had my internet provider's email server for a long time!... Mark from scale 4x4rc.

 

[spankrjs 80]

I thought I recognized that member name!!

I sure miss the scale4x4org site 

[Cambodian Tire 0]

Yes I miss it as well. I'm going to post some stuff here soon. My boys just acquired two new rc's yesterday, so I dug out my Bruiser which brought me here and whadya know, first thread thread is right on topic?

 I'm happy to come across a familiar name! I hope you are still Jeeping? Our family of four just had an overland trip this summer throughout the Yukon, sadly only had two weeks so Alaska will have to wait till next summer).

..Mark

[spankrjs 80]

14 hours ago, Cambodian Tire said:

Yes I miss it as well. I'm going to post some stuff here soon. My boys just acquired two new rc's yesterday, so I dug out my Bruiser which brought me here and whadya know, first thread thread is right on topic?

 I'm happy to come across a familiar name! I hope you are still Jeeping? Our family of four just had an overland trip this summer throughout the Yukon, sadly only had two weeks so Alaska will have to wait till next summer).

..Mark

Oh yes, still in to Jeeping!! I have to go pick up a new front driveshaft for my red Scrambler, bent the badword out of the front shaft in TX. Still have my Green Scrambler, a '85 Spring Special CJ-7, a '86 CJ-7, and traded my '22 Gladiator in on a '24 392.

Glad your boys are into RC's, too 

[Cambodian Tire 0]

I remember your Scramblers from the 1 to 1 threads). You have the holy grail of Wranglers with that 392!!... that is a collectors Jeep in the making, almost too nice to wheel haha. 

 Someday I will get around to installing Jeep speed kit and a 5.7, I have yet to uninstall the motor from the donor 300. I will only find the time once I have to ie. my v6 dies:(.