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Which Transmission Option?......

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Alex_McMillin

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In planning some winter projects for the TR4, I wrestling with which transmission I should install. Keeping in mind things like reliablability and project cost. I have a type-a overdrive transmission and all the bits already in my possession, but was also considering the Toyota 5-speed conversion. I am not worried about the car being 100% correct, just fun and very driveable.

What's the general feeling/thinking on this forum?

.........Alex
 
Andrew Mace said:
Hmm...virtually as-original "seven-speed" gearbox v. "aftermarket" five-speed? I'd go with the OD that you already have!
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:iagree:
 
Goes double for me. The 7-speed semi-automatic is more fun, more driveable, and with a modicum of care, quite reliable.

IMO the Toyota conversion is primarily for those who can't afford a real overdrive :smile:
 
I have the original OD unit in my 3A. Took a little while to get the bugs out of it after it was professionally rebuilt.... but really like it now. That being said...my friend with the Toyota 5 speed...he loves that also. Guess its the old pay your money take your choice situation. Gil NoCal
 
a fully rebuilt original Tranny and A over drive with all the upgrades is around 3500, wishbone classics did mine, good guy, and its a direct bolt up, the 5 speed does require lots of work,

like they say the devel you know is better that the devel you dont know

I vote original and rebuilt

Hondo
 
Geo Hahn said:
For me the A-Type OD is the way to drive. Lots of flexibility and quite reliable.

hondo402000 said:
a fully rebuilt original Tranny and A over drive with all the upgrades is around 3500...
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Although Quantum Mechanics (where I got mine) has a very good rep and offers the whole enchilada for 2575 (and your non-OD core) or 2750 outright.

https://www.quantumechanics.com/categories.php?op=newindex&catid=7
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Hands down if you have a decent od I'd go with that. Its unique and definitely part of the fun and feel of the car. And you can get them from small but reputable rebuilders for less than $2K occasionally , Ed Woods comes to mind for example. And if you are real lucky and a scrounger like me, they come a lot cheaper than that, but not rebuilt.
 
TR3driver said:
...
IMO the Toyota conversion is primarily for those who can't afford a real overdrive :smile:
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I was faced with the same decision when re-doing my TR3. I could have afforded the Triumph overdrive, but since I really didn't care about originality, I opted for the Toyota box instead for several reasons. Unless you're racing the TR, the seven speeds is really an overkill. The TRactor motors are quite flexible where it isn't really necessary to be split shifting. I driven TR ODs, and yes, they are fun, but after awhile that wears off and all you wind up using the OD for is on fourth gear. What the original four speed lacked was OD AFTER fourth gear...a gear to allow lazy rpms at highway speed. The Supra gear ratios also are very close to the original TR ratios so 1 through 4 will feel the same. The Toyota is also bullet proof. It's why I was able to buy one off of e-bay for $150+$50 shipping. The supply is big and demand small because they didn't break. Although that may be changing now that it seems these boxes make good swaps in all kinds of cars. I also feel that the Toyota boxes shift better then any TR I've driven. Not to say that a properly sorted TR box isn't good, but there's that something in most Japanese boxes that make them feel so good when shifting. My Miata gearbox exhibits that same feeling.

Of course, I wasn't faced with the fact of actually HAVING a TR OD in my possession, as the original poster has. In that case, it's a no-brainer...install the TR OD. But for those of you who are contemplating which way to go without having a TR OD, take a drive in a TR with a Toyota Supra tranny installed and you might be quite surprised on how good the conversion is.

Edit: Oh, one thing missing from the Toyota transmission that you may not like...oil leaks.
 
martx-5 said:
I driven TR ODs, and yes, they are fun, but after awhile that wears off and all you wind up using the OD for is on fourth gear.
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Not for me. After 35 years, I still use 2nd OD almost every day. And even just using 4th OD, with the Toy box you can't drop down a gear at full throttle, which I also do almost every day.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Edit: Oh, one thing missing from the Toyota transmission that you may not like...oil leaks. [/QUOTE]
Strange, they seem to have left those out of my current A-type as well. But if it did leak, adding more oil is as simple as popping the plug out, lifting the dipstick and pouring some in. Just checking the level in a Toy box is a lot more hassle than that.

To me, the electric overdrive is part of what makes it a British sports car. I have driven the Toyota box (in a Celica) and it is very nice (although the Miata is nicer). But it's not "old British sports car". If all I wanted was "nice", I'd be driving a Miata.
 
Well, I think my decision is pretty easy. Type-A OD it is. Seeing I pretty much have everything already. I am looking forward to the project and I'm sure I'll have more question along the way.

Thanks everyone for your comments.

.........Alex
 
Art-

I agree with you - from a functional standpoint my main use of the overdrive is highway cruising in 4th overdrive. I don't work through the intermediate gears unless by accident where I've left the switch engaged. Given two sitting in front of me though, I would put in the od because I just really like that automatic capability with the switch. Its just flat out fun. Not that any TR isn't fun anyway..

Randy

ps my rear oil seal on the engine dwarfs any puny gearbox or differential leak (I have all three!).
 
Make sure you replace all the switches too, I bought new switches, and left the old ones in and now I am regreting that decision, one is sticking so I have to pull the tunnel out to replace them, but thats after I get my alternator wire that fried, and all the gauge bulb holders replaced this weekend

Hondo
 
TR4nut said:
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ps my rear oil seal on the engine dwarfs any puny gearbox or differential leak (I have all three!).
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This whole business with the rear main "oil seal" on the TRactor motors can be fixed by using the correct size centering mandrel, not the size that is shown in the service manual. I set mine up according to info garnered from this forum (pretty sure it was Randall), made the right size tool form a piece of delrin, and (knock on wood) have NO ENGINE OIL LEAKS in the 2500 miles since the engine rebuild. The only place I'm getting a <span style="font-weight: bold">slight</span> leak from is the differential gasket.
 
GilsTR said:
Just remember...don't use that OD in 1st or reverse !!
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You mean just because it doesn't work? I forget and leave the switch on far more often than I like to admit, but it doesn't hurt anything. Just makes that first shift kind of a long one (from 1st direct to 2nd OD).
 
martx-5 said:
This whole business with the rear main "oil seal" on the TRactor motors can be fixed by using the correct size centering mandrel, not the size that is shown in the service manual.
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Which, BTW, are available from either Joe Alexander https://www.the-vintage-racer.com/ or TRF.

Another problem can be that it is very difficult to judge wear in the original seal. The clearance is supposed to be tight enough that worn main bearings can allow the crank to drag against the seal and wear it away. The obvious cure there is to replace the seal (or send it to Joe for reconditioning).
 
It's good to hear someone's making the correct size. The one offered by Moss measured <span style="font-weight: bold">0.005" larger</span> then the dimension in the service manual which is too large. One of the guys in out Triumph club used the Moss tool to assemble his engine. I had borrowed the tool to use it for my rebuild but brought it back to him and told him the dimension was too large. He still had his engine out of the car, but was stubborn and didn't want to correct the problem. Needless to say, his rear main leaks pretty good.
 
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