Engine and Transmission Tech

Nice article about your TR-6 shifter solution, Kris. That was good reading. That was a good solution for the shifter! That 5-speed sounds like the right combo for your six. That's the M77 right?? Or is it a T50 maybe?

My Vega came with a Saginaw-4. Not bad but I really wanted dog-rings, straight gears and better overdrive options. I couldn't find anyone making parts for the Saginaw. There are some pretty cool things you can do to a T5 for racing though. I think you've found a pretty smart solution to your needs.


I thought it warranted a new thread. SO transmission options: I've got some info about the T5's that might be helpful. As for the T5 there are some questions I had about the TR-6: I was thinking about the shifter location. This is also a problem with the Vega. How far from the bellhousing is the shifter location for the TR-6?

The T5's have three shifter locations: GM S10 (right near the main housing), GM F-body (at the end of the tailhousing), Ford... well every other T5 (about 3/4 back on the tailhousing). It is possible to build a World Class version of the T5 using anyone of these tailhousings...

The T5 is not the cheapest solution. It is light and plentiful though.

Quote: "That 5-speed sounds like the right combo for your six. That's the M77 right?? Or is it a T50 maybe?"

To be honest, I don't know Rover transmissions well. I bought it off the net from a guy who raced 215/Rover-equipped TR7s. He said it was a TR8 gearbox. One of the shifter remote ears was broken off, so I bought a back case half from somebody else on the net. The back case half came from a TR7 5-speed as I recall--been a few years.

Quote: "I thought it warranted a new thread. SO transmission options: I've got some info about the T5's that might be helpful. As for the T5 there are some questions I had about the TR-6: I was thinking about the shifter location. This is also a problem with the Vega. How far from the bellhousing is the shifter location for the TR-6?"

The stock 4-speed 'box has the shifter 23 inches back from the engine side of the bellhousing. The shortened TR8 remote I made puts the lever 23-1/2 inches back from the engine side of the TR8 bellhousing.

I thought about a T5 but then I saw this TR8 'box on the net. What I'd read about the TR8 gearboxes was that they shifted well. The gear ratios seemed good for my TR's 3.7:1 rearend too. As I mentioned in another post, I'm thinking about getting a Muncie so I can drop my NOS '66 Hurst 4-speed into it. As Curtis noted, that's really a step backwards, but man this Hurst shifter is killer cool. Having that muscle-car era shifter with its white 4-speed knob protruding from the floor of the '6 would be mighty rad....

Kris

Sounds like you found the right option for you. I know what you mean about the "Rock Crusher" sound. I love it. I'm actually building my race T5 with straight gears. I just ordered the kit yesterday. Here's a pic of the kit



That should make some noise, and use less power. I picked 2.94, 1.94, 1.34, 1.00 ratios in gears 1 thru 4. I might just use the stock overdrive ratio for cruising. I'd likely not need it for power... I'm pretty excited about getting started on building it...

Kit looks great. That should be a fun winter project.

Does anyone have a good picture or could take one of a T5 for the forum.
I'm looking for one of the shift fork arrangement on the top cover. What I need is the top cover removed, layed on it's back to show the arrangement of the forks and shaft.
Thanks if anyone can supply it. My manual just does'nt have a good pic.
JB

If it doesn't happen before I get my WC T5 I'll get some pix for that...

May be overkill.. Toyota Supra Turbo R154 mated to a Buick 215 bellhousing via a Jeep AX15 adapter from Novak in Utah.



Greg

I'm in the planning stage for building an MGBGT using a 3.9 Rover motor. This car will be "street legal" but used primarily for hill climb races in the northwest. I just signed up to the forum and what I see on transmissions is that the T5, with straight cut close ratio gears, may be the best choice for my purposes. Compared to the other options, is this a relatively light gearbox? Any comments/suggestions are greatly appreciated! Bob Sherman, Hillsboro, Oregon

Pretty HOT, Greg. That's a pretty stout transmission. Is the input shaft long enough for the adapter plate?

I don't know much about the R154 so I can't comment on the weight. I've heard it's pretty tough though. As for the T5: It's VERY light. 75lbs. That's at least 15lbs lighter than my Saginaw 4 I think. I'll double check that tonight. I know the Muncie T10 in the aluminum cases were pretty light at about 70lbs. AT least I know Richmond gear makes a 70lb. version of the T10 patterned after the original aluminum T10s...

Here's a link to the company I bought the straight-cut dog-ring gear set from for my T5:

[www.gforcetransmissions.com]

Hang on to your wallets! LOL. I think the price is worth it for a light racing 5-speed. Especially if you are making power in a light vehicle where weight is a serious consideration. (Well to be honest, weight is ALWAYS a consideration to me.) Hope this helps, Bob.

The weight I've seen listed for Toyota five speeds was 35kg... which comes to about 77 pounds. That's probably within the margin of error (wet vs. dry, with shifter vs. without, etc.) It's hard to know how different people weight stuff! The Tremec TKO-600 is a heavier duty version of the T5... and heavier weight too, at about 95 pounds. The Tremec T56 is 6-speed is way too heavy, at about 125 pounds.

The R154 and adapter work just fine with the 215 bell. Input shaft length is no problem.

Greg




Edited 1 time(s). Last edit at 11/09/2007 09:39PM by Greg55_99.

Thanks for the info! Those g force gears look great! Bob

Have they had any breakage problems with the shifter dogs? The ones on the upper gears look a little weak.

Jim

I've been researching for a month or two and I haven't ran into complaints of dog breakage... I'd take that with a grain of salt though. It is a T5 in the end. They are a pretty light trans... I've read of a number of road racers using with luck though... One thing I haven't found is used G-force gear boxes so they are either too good to sell or frag beyond all recognition. LOL! I'm not close to worried about it for my application:

2300 lb. Vega. 355 lb/ft torque if I'm lucky... You guys will be the first to know if it does break though. Unfortunately the soonest I'll be testing it is in a year... SHOOT!

I forgot to mention that I weighed the Saginaw 4 and it came out to 105 lbs.! That's a weight savings of 30 lbs. I was pretty surprised that it was that heavy actually. That's a big step for overall weight reduction...

SWEET! I just won an auction for a WC T-5 from a '90 V6 Camaro. It has the smaller 14-spline input shaft for the 4cyl and V6 cars but has the WC internals. Should work great with the G-force upgrade!

Here's some fun.... I hunted down a '62 Special 4-speed, which I hope I can mate to my NOS Hurst shifter. Doesn't feel any heavier than the Rover 'box and the shift lever emerges in precisely the right spot (with the stock lever). I'll finish building my TR with the Rover and rebuild this unit as a side project for a future date. Always love taking something crusty, yanking it apart, bead blasting, cleaning, painting, and producing something that looks nearly new.

More detailed writeup on the expedition to retrieve it, here: [www.startribune.com]





Edited 1 time(s). Last edit at 11/30/2007 10:12AM by motormouth.

That would be the Saginaw 4 speed. A good reliable box that'll handle some big inch motors. Very similar to the Muncie but heavier with that cast iron case. It is possible to fit the overdrive from the 3 speed Saginaw to it if you can find one.

But make sure of the ID first. It seems like maybe the Saginaw had all three levers on the side cover.

Jim

It's a Borg Warner T10, which is different from a Saginaw as I understand it. Pictures I've looked at seem to show the Saginaw being cast iron throughout, and bigger and heavier. The T-10 has a cast iron case (early on; aluminum later) and an aluminum tail housing. It was continued on as the Super T-10, with Saginaw and Muncie used concurrently.

Good tip on possible overdrive. I'm interested in that for highway cruising, though part of my nostalgic reason for picking up this 'box was to see if I can fit my NOS Hurst shifter to it. That is built for the Saginaw, but it looks like the shifters are similar and I'm hoping I can combine the Hurst shifter with the T10 linkage.

Hey Chris. Thats a nice article.
Id like to get back to Rohners some day. I have been through French lake many times. I found a new place in Iowa last October but did not have much time to go through it.

You, Nic, and I should get together sometime.