Transmission teardown

[CrankyOldMan]

Well, I suppose I should share some of the lessons that I've learned from tearing down a transmission in preparation for a final drive and 5th gear swap. I haven't gotten to the point of rebuilding it yet, so for now it's just some tips and tricks for the spots where the manual claims you need a $500 specialty tool. I'm not going over all of the basic steps from the manual: you can read that on your own.

Of course, all of this comes with the standard American "do this at your own risk, I am not an expert, I do not guarantee the results of any modifications you do, etc."

My overall plan is to combine the first four gears and final drive of a C56 (Celica/Yaris TS) with the 5th gear of a 1st gen Matrix. As of now, I have the C56 disassembled and the Matrix 5th gear, but I don't have a Yaris compatible gear casing to put them in.

Here's a brief listing of some semi-specialized tools that will be useful and/or essential for tearing it down. I get my stuff from Harbor Freight since it's cheap, and I don't use it daily.

• Bearing separator and gear puller set
• Bolt puller set
• 3/8" breaker bar
• metric socket set: at least the 10, 12, 14, 17 & 19 mm sockets
• metric allen wrench set: at least a 6mm, allen socket is also useful
• impact gun: I use a pneumatic 1/2" driver because I already have a large compressor. If you don't have a compressor that can drive one (15+ gal, 30+ cfm@90 psi) then consider buying an electric driver instead.
• Gasket/paint scraper with a sharp edge
• large adjustable/crescent wrench
• deadblow and/or plastic mallet, ball peen hammer
• brass bar
• misc screwdrivers, pliers, etc.

Removing the end-cap is a bit of a pain because it's held on by RTV sealant and two slotted pins. After a few good whacks with the deadblow and a few minutes under the torch, it still wouldn't come off. I used the sharp edge of my scraper tool to pry one end open, then repeated from the other side. DON'T use a screwdriver, you'll most likely scratch/mar the mating surface and make it leak once you put it back together.

The bolt puller set is used to get the 5th gear hub off AFTER you remove the c-clip and unbolt the selector arm.


Once the hub is off, 5th gear slides right off and makes room for the larger gear puller. The large nut on the end of the output shaft has a spot that's been bent in. Drive a flathead screwdriver behind it to bend it back out. Use a large crescent wrench to remove the nut.


I tried to get a shot under the gear puller, but the lighting was terrible. It's pretty obvious where the gear puller goes.


And here's the 5th gear area, sans gears.


If you're like BlueVitz-RS and have access to the Toyota "Puller Set B", then by all means, use it. If you're like most of us though, and only have access to what we can get at the store, these tools should serve you well.

[CrankyOldMan]

Minor setback on the xB teardown: the 5th gear hub does NOT have the two threaded holes. There isn't enough room to get a bearing separator on the hub, or on the 5th driven gear, mostly due to the selector arm rod. Off to Harborfreight for another tool...

Update:

That tool from HF didn't look like it would work. It's much larger in reality than the pictures seem to indicate. The feet were almost 1/4" thick, so there was no way they would fit without being ground down, and then I doubt it would be strong enough to hold on. The solution then? a 4" Posi Lock gear puller. I borrowed it from a friend (who borrowed it from a friend) because I can't swing $150 to buy one of my own right now. I put the feet under the hub to prevent damage to the gear teeth and cranked it right off. The driven gear was removed the same way that the others were (using the large separator) because the feet didn't quite fit into the groove around the gear. I think that a 3" Posi Lock would have been able to fit, but that's another $150.

[CrankyOldMan]

Update time! (pics later this week)

I snagged a used C50 from a Yaris and did a full teardown on it. Thankfully the 5th gear hub was the kind with threaded holes, so I didn't have to get any additional tools. The input shaft from the C56 fits without any obvious issues, but the output shaft requires a larger ID bearing. I don't have the proper tool to pull the bearing, but a classmate has a slide hammer set. The 5th gear hub from the C59 looks like it will fit without issues, but I can't confirm that until I have access to the press in the other shop.

On a side note, the C56 gears look rather abused, and will likely have to be replaced before the final build.

[mazilla]

Tag...keep up the good work!

[fnkngrv]

great work Cranky...I know that you have discussed this in previous threads, but what is your end goal with this project?

[CrankyOldMan]

Ultimately I want to get the "xB final drive" swap, but mated with 1st - 4th gears from the C56 for even more torque in 2nd - 4th, and the 5th gear from a 1st(?) gen Matrix for lower highway cruising RPMs. It's proving to be rather expensive to research, but the end result should be a DIY that can be followed for much less.

I've decided to go with gear ratio changes instead of engine mods to pursue a "CARB legal" solution that doesn't involve regular removal of exhaust/intake/ECM components. Not all states have annual emissions testing, but for those that do, this could be a great alternative.

I was going to post a link to the fatboyraceworks gear ratio comparator, but the site appears to be gone.

[CrankyOldMan]

I'm thinking that I should start taking pictures so that I can start a DIY thread. I managed to get the output shaft from the Celica to fit in the Yaris gearbox today. A few minor hiccups, but nothing that a bearing separator and a 100 ton press couldn't fix!

The bearing below the final drive helix is different on the Celica, and is too large to fit on the Yaris/xB. It turns out, however that the larger diameter is only the inner race for the bearing, and can be pulled off. I'm not 100% happy with the result, as the channel for the retaining clip is now directly on the bearing rollers, whereas the Yaris/xB have a solid journal surface.

The other problem was that the bearing between 4th and 5th on the Celica output shaft didn't fit into the hole on any of the other gearbox housings. A quick session across the hall with the 100 ton press, a bearing separator, and a donor output shaft remedied that snag.

Yes, pictures would be very helpful. I have a camera, but I don't have a card reader for xD memory, or the right cable to offload them. Crap.

[fnkngrv]

need an xD reader donor? haha...this is defintely a subscribed one for me. Do you feel as well that your work will net a higher top end than the stock Yaris which is said to be in the very low 140s?

[CrankyOldMan]

Ok, here's a chart showing the relative top end speeds at 6000 RPM for a few different combinations. The "Stock w/ 4.315 FD" is the already-proven "xB final drive swap" mod (orange line). My custom gearbox is the "celica 1st-4th and FD, matrix 5th in a Yaris case" mod (dark blue line). A few variants are shown for comparison if you want to mix-n-match your own gearbox.

To answer your question, fnkngrv, this will have a slightly lower top speed, but will have better acceleration in 2nd-4th. I'm not worried about where the top end speed falls, because the speed governor kicks in around 107 or 112. That, and they start taking away your license at 100 if they catch you. I'm putting in a taller 5th gear to drop 70mph RPMs from 3500 to about 3000.



Some interesting things to note: Changing 1st from 3.545:1 to 3.166 with the 4.315:1 final drive results in an almost identical top end/acceleration from 1st. If you want more torque in 1st, leave the stock 1st ratio in place. I swapped it to get a smaller RPM drop between 1st and 2nd, so I can land closer to the peak torque.

[CrankyOldMan]

Here's a few pics to illustrate what I was talking about earlier.

This is where the snap-ring groove is on the C56 output shaft:


This is the bearing that is different on the C56:


These pics came from a thread at NewCelica.org where a C60 was rebuilt.

[rob323]

Good luck with the C56, it's a great gearbox.

[CrankyOldMan]

Originally Posted by rob323

Good luck with the C56, it's a great gearbox.

Didn't you shoehorn yours into a C151 housing? I remember reading something about that on YarisFans, but don't recall the details off hand. Did you have to do anything fancy to get the bearing preload set on the differential?

[fnkngrv]

There has got to be a way to get the 1nz to a higher top speed...at least I hope there is!

[CrankyOldMan]

The biggest problem that the Yaris faces with top speed is frontal area. It's a tall car and even though it's egg-shaped, the total frontal surface of a body is a major factor in determining its top speed. Even if you got a bonkers overdrive ratio (like 0.6:1) for 5th gear, our 100 little bronies can't cope with the aero issues beyond a certain speed.

Here's a more in-depth evaluation of the ideas.

[why?]

you could always do some aero mods, although you'd have to figure out what was legal for your class.

[rob323]

Originally Posted by CrankyOldMan

Didn't you shoehorn yours into a C151 housing? I remember reading something about that on YarisFans, but don't recall the details off hand. Did you have to do anything fancy to get the bearing preload set on the differential?

My gear box is - C150 bellhousing and end cap, C56 centre housing with C56 gearset (gearset is too long to fit in C150 centre housing), TRD4.7:1 final drive and TRD lsd.

Setting that preload was painful. I had an assortment of shims from 3 gearboxes and played around with combinations of them until I got it close to the factory spec. The torque wrench I used to measure this was nothing more than a foot long bar attached to an inner cv joint with a fishing scale hooked on to the bar. Dodgy at best but seems to have worked.

[fnkngrv]

Originally Posted by CrankyOldMan

The biggest problem that the Yaris faces with top speed is frontal area. 100 little bronies can't cope

I have the sedan so at least the tallness is not as drastic as the LB. Also, I left the stock HP/Torque in the rearview last summer and it is only going up from here. All of the information and food for thought you provide is appreciated and great to ponder over that is for sure.

[CrankyOldMan]

Originally Posted by rob323

My gear box is - C150 bellhousing and end cap, C56 centre housing with C56 gearset (gearset is too long to fit in C150 centre housing), TRD4.7:1 final drive and TRD lsd.

Aah yes, that sounds familiar. What kind of issues did you have with the mounting brackets? I've got another thread around here where I documented the differences between four different gearboxes, and it can be pretty crazy even with the "same" trans model number.

Setting that preload was painful. I had an assortment of shims from 3 gearboxes and played around with combinations of them until I got it close to the factory spec. The torque wrench I used to measure this was nothing more than a foot long bar attached to an inner cv joint with a fishing scale hooked on to the bar. Dodgy at best but seems to have worked.

Thanks for sharing your setup! I've been thinking of doing the same thing, but there's a bit of calculus involved: you have to be able to account for the mass of the bar and axle socket and how it changes the load. My plan was to use a small wooden dowel and a calibrated weight from a balance style scale, but the gearbox would be in the "normal" upright position. You've got the right idea with the length markings though.

As far as shims go, I may just bite the bullet and get a few full sets since they're only a few dollars each.