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Toyota 5 Speed Conversion

I decided to do the popular Toyota 5 Speed conversion for a few reasons... 1) The original transmission didn't sound or feel real well, so a rebuild was in order, 2) A sychonized 1st gear would make the car far more enjoyable to drive for me, and 3) I wanted the efficency and cooler operation of a modern transmission, and an improved 5th gear.

The Healey drives absolutely fantastic with the Toyota transmission in it. The way it feels... the synchro'd first gear... the ratios... it's just perfect. Like they were made for each other.

Here's the contact info of the guy you need to talk to if you want to do this:

Pete Delaney
Healey 5-Speed
PO Box 561
Harrisburg, NC 28075
704-455-8504 (fax)

He's also got an AOL email, but I never had any luck reaching him that way. Any time I used the phone though, he either answered directly, or I left a message and he responded within a reasonable amount of time. Nice guy... seemed like he'd be very helpful for those who needed it. The kit was soon on order, and I recieved it in a reasonable amount of time.

The instruction manual that came with the kit was very thorough, but also seemed very outdated... as if the kit has changed pretty significantly since it was written. But it was still easy to follow, and I had no issues. The picture below shows everything that came with my kit (for a BJ8). The only thing in the picture that Pete didn't supply was the transmission itself. You can click on the pic for a bigger version.


The hardest part (which wasn't very hard) was finding the correct Toyota W58 transmission... since the entire W series really has no markings or identification from the outside. I got mine from a '87 non-turbo Supra, and then counted the gear turns in 1st, 5th and reverse to make sure I had the right trans. http://en.wikipedia.org/wiki/Toyota_W_transmission.

The only way to know for sure you've got the right transmission is to count the gears. Here's how I did it:

On the transmission input shaft:
I simply stuck a magnetic pointer on the shaft that had a piece of tape rigged on it, and then stuck a piece of tape on the bellhousing, lined up with the tape on my pointer. So this would give me a mark for 1 turn on the inlet.

On the transmission output shaft:
I made and printed out a sort-of "degree wheel" thing. It had increments that divided up one revolution into 0.1 whole mark increments with 0.05 half marks in between. Then I stuck this on the output shaft with double sided tape. I stuck it on "backwards", facing the bellhousing, since that's where I would be, turning the input. That way I could turn the input and record the output easily.

Then, put the transmission in gear. Remember that if you DON'T have a shift lever on at the time, and are just moving the shift lever housing... remember that you're actually looking at the gears in reverse... so 1st gear is actually back and to the right. Took me an hour to figure out what I was doing wrong :)

Then, simply rotate the input shaft in whole turns, and count resulting output turns. Divide input by output and you have ratio. And it really doesn't matter how many turns you do... because it's the relationship between the two that matters. The more turns you do, the more accurate you'll probably be. So if you turn the input 27 times, for example, and see that the output turned approximately 8.2 turns, divide the two and you get 3.29. First gear is supposed to be 3.285, so you've got the right first gear.

I checked 1st, 5th and reverse this way... with all three of those, I could be 200% sure I had the right transmission. Click on the picture to the right to see my pointer and degree wheel.


A speedometer works via a rotating cable, and this cable moves via two gears - the DRIVE gear, which is the gear that's actually inside the transmission on the output shaft, and the DRIVEN gear, which is the gear that you insert through the side of the transmission. The Healey 5 Speed kit comes with a new DRIVEN gear... which I'm assuming, long ago, someone figured out was the correct gear to mate to the DRIVE gear for an accurate speedometer. However, keep this in mind...

The 5 speed conversion kit was (I think) designed around transmissions coming out of early 80's Toyota Supras. If your transmission comes from anything else - even from later Toyta Supras, you may have a minor problem - using the DRIVEN gear supplied with the kit, it's possible the DRIVE gear on your transmission is not the correct mate for it. I had this problem, but I've dealt with this a few times in the past on other cars, so I knew to look for it. Most car makers have different drive/driven gear combinations (even within the same car model family)... and different gearing requires different numbers of teeth, which often requires diameter changes to the drive/driven gears to get the speedo to work correctly. As such, it's possible to mismatch them.

When I first put in the driven gear that Pete supplied, I looked down through where the shifter goes (with the shift lever retainer removed), and saw that the gears weren't touching each other. The drive gear was too small in diameter to mate with the supplied driven gear... so the speedo cable would not turn.

After quite a bit of research, I figured out what drive gear was supposed to be in the transmission - it's Toyota part number 33481-22020 (SEE UPDATE BELOW!). That will mate correctly with the driven gear supplied with the kit (at least for late BJ8 w/factory rear diff... don't know about others). It's actually pretty easy to change out the drive gear, but it does require pulling the back housing off the transmission. Here are a couple pictures....

The difference in the gears is subtle. The correct one is pictured here still in the bag, and the incorrect one that I took out of the transmission is to the right of it.

Here you see the rear housing off the transmission, and the gear installed.

- - - - - - - - - - - - - - - - - - - - - - UPDATE 1/15/2011 - - - - - - - - - - - - - - - - - - - - - -

After getting all this done and back together, I found that my speedometer wasn't reading correctly!  It was about 10% off.  The combination I listed above IS correct... those are the two gears that are supposed to mate together... but apparently this is not correct for all Healeys.  My guess is that the gear combo listed above is correct for older Healeys with a 3.54 rear end.  Mine, being a BJ8, has a 3.90 rear end in it... so I think this is why it was wrong.

So after about 5 million hours of research, and a couple failed attempts at getting it right, I finally found the correct combination.  If you have a Toyota W58 in your BJ8 Healey, you need to get Toyota gears 33481-22030 (DRIVE GEAR) and 33403-29145 (DRIVEN GEAR).  Fortunately, you CAN get to the drive gear without having to take the transmission completely back out of the car.  The photo here shows what it looks like to swap the gears with the trans still in the car... along with a photo of the gears still in their bags.  I bought the gears from ToyotaPartsZone.com.

Something else to think about... while I was messing with all this, I figured I'd go all the way, so I calibrated my speedometer.  Otherwise I may never be able to get the thing to read correctly, which was unacceptable given all the time and effort I put into it.  I'm talking about bench calibrating, to reset it back to factory settings, so to speak, and to help remove any error that may have developed over time due to weakening magnets.  Using this fantastic article as a guide, I figured out the exact RPM that my hand drill was turning at, and then using the number printed in the front of the speedometer, was able to figure out how fast it SHOULD be indicating at the drill RPM.  Doing that, I then repositioned the needle to reflect that speed at that RPM.  This got it close.  After this, using a GPS, I went for a drive and noted the error at 60 MPH, and then went back and tweaked the needle position accordingly.

When it was all over, I now have a speedometer that reads nearly perfect from 20MPH to 60MPH.  Above and below that, it does go off proportionally, but that range covers nearly all driving conditions... and it's easy to remember where 70MPH actually is, so I now know my correct speed at virtually all legal speed limits.



While you're tearing the transmission out, it's the perfect time to update to a proper rear crankshaft seal. Here's a separate page I created for that topic.


Here's some photos removing the original stuff...

Below, from left to right: The first pic is right after finishing the rear crankshaft seal conversion.  The next pic shows the rear engine plate reinstalled. Next, you see the supplied bearing pressed into the flywheel. And the last pic... don't miss that the flywheel is marked! The "1" on the flywheel needs to be pointing straight up when the engine is at TDC. I'm guessing it's a balancing issue.


The Healey uses two "Dowel Bolts" as the mechanism to align the transmission to the engine. These are very important; without them, you risk wiping out bearings, causing major vibration problems, or who knows what else. The dowel bolts simply take the place of two of the bolts that mount the bellhousing to the engine plate. Here's how the bolt layout goes...

A "dowel bolt" is nothing more than a bolt with a long unthreaded section whose diameter is held to a very close tolerance... and then this mates to a close tolerance hole in the bellhousing and engine plate. I was missing one of my original dowel bolts, so after a rediculous amount of research, discovered that dowel bolts are really just AN176 aircraft bolts. The picture to the right shows the bolt I used - it's pictured next to the one original dowel bolt I still had.


As mentioned above, the dowel bolts are supposed to closely align the bellhousing to the engine plate, which in turn keeps accurate alignment between the engine crankshaft and the transmission input shaft. Thankfully, due to needing to research this because I was missing one of my bolts, I stumbled across a slight issue with the Healey 5 Speed conversion...

I'm not sure if they're all like this, but I discovered that my conversion bellhousing was NOT drilled for a close tolerance fit with the dowel bolts. This means that there was no alignment happening... they'd fit snug in the engine plate like they should, and then be sloppy within the bellhousing itself. This would result in the trans input shaft doing all the alignment work, into the bearing in the flywheel... and with the weight of the transmission hanging off the back, this would surely result in some side loading on the input shaft.

I'm not sure how critical it is on these kinds of cars, but I know with the '68 Camaro I had, anything more than a few thousands of misalignment was too much, and could cause shortened part life, excess bearing wear, etc. So I didn't want to take that chance...

I ended up making "circular shims" from some flat brass shim stock, sized to fill the gap between the bolt O.D. and bellhousing I.D. I then had to take a few tenths off the O.D. of my new AN176 bolts to get the fit "just right" (bolt held in drill, fine sandpaper). Then I just slipped the bolt with the shim into the bellhousing, and installed. The result was the dowel bolts doing what they are supposed to do - aligning the bellhousing to the engine plate, and therefore the trans input spline to the crankshaft. Pictured to the right is the shim I made.

The rest of the installation was pretty straightforward. I followed the installation manual, and it was just a matter of bolting everything up. Here are some more pictures of the installation...


1. The push rod for the slave cylinder - the new one that came with the kit - was too short. I ended up not having enough clutch pedal to fully disengage the clutch. I'm not sure whether or not this was a problem with the kit itself... it's possible my slave cylinder is an aftermarket one that doesn't quite have the correct throw or something (it came with the car, so I'm not sure). So I ended up actually using the original pushrod. I made a metal "button" that I crimped in place into the hole in the end of the push rod, so that it wouldn't bend or crush. Other than that, it fit perfect, and everything worked perfect.

2. The Healey transmission hump obviously has a rubber boot in it that goes around the shift lever... but I noticed on the new transmission shift lever retainer that there appeared to be a groove around the top where it could have its own boot cover. I thought some extra dust protection sounded like a good idea, so I set out to figure out what it was supposed to be... and found it - Toyota Part No. 33555-35040, off some Toyota trucks.  The pictures below show this boot installed...

And here's what it all looked like when the job was done. No way to tell what's underneath...

If anyone has any questions about any of this, feel free to send me an email!


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