Sourcing a real road race transmission | Project vintage race Mustang

Tim
Update by Tim Suddard to the Ford Mustang Fastback project car
Jan 23, 2022

Don’t install a used transmission in the race car.

That advice came from Cobra Automotive’s Curt Vogt, our guide on our 1965 Mustang vintage race project.

He begged us not to use a shortcut and fit a used transmission. He told us how locking up an old, unknown gearbox at a track like Road Atlanta would be scary and dangerous. Curt’s hard knocks would save us from making the same mistakes.

He recommended a Roltek T-10. This Chevrolet-based T-10 four-speed is legal for our HSR class–no five-speeds allowed–and has been extensively modified to be both lighter, stronger and easier to service than a stock T-10.

Some of these modifications include:

  • 9310 nickel alloy gears
  • Positive dual-rail shifting
  • Unlimited gear ratio replacement
  • Lightened rollerized reverse set up
  • Gears engineered for extra strength
  • Quick and easy assembly and disassembly
  • Face tooth engagement for positive shifting
  • Caged roller bearings on main and cluster shaft
  • Reverse idler and input shaft

We also ordered their FIA billet shifter kit designed specifically for the early Mustang. At a bit more than $500, this shifter seemed a bit pricey but Curt insisted this was another place where the money would be well spent. Missing shifts at high rpm can get even pricier, so we took his word for it.

Add in the transmission, and we had just put $4500 into our Mustang, but Curt assured us that we shouldn’t cut corners here or with the rear end.

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Tom1200
Tom1200 UltraDork
1/19/22 12:04 p.m.

$4500 for a race transmission is not outrageous; the extra $500 seems to make sense to me as well.

BUT

Playing devil's advocate and with all due respect to Mr Vogt; how often do trannies actually lock up?

The ones on my Datsun that broke simply shredded the gear; 3rd to be exact. I'm asking because I'm curious about whether or not this is common to V8 vintage production cars. It's not my usual I'm cheap and would rebuild a used box, I really do want to know.

 

 

 

Rotaryracer
Rotaryracer Reader
1/19/22 2:11 p.m.

That looks slick.  Not to rub Brakleen in any wounds, but there's another option that's a bit more cost-effective.

The SCCA American Sedan guys are largely running the AutoGear M23...basically a seriously beefed-up Muncie with a bunch of trick parts and enhancements to survive being thrashed at 7500 RPM lap after lap.  George and the gang are great to work with and are very committed to the sport, with ongoing enhancements based on racer feedback.  The price has come up slightly since I bought mine back in 2017 (as all things have), but it looks like they are now at $2,775 for a complete, brand-new gearbox.  Figure in another $8-900 for a Long 4-speed shifter (which works just fine with a bit of fettling) and you're under $3,700 complete....less if you go for the slightly less robust Hurst or equivalent shifter.

The T5 that came with the 3rd gen Camaro developed an appetite for eating third gear, and the veterans used to run a "three-trans" strategy - one in the car, a rebuilt one on the trailer, and a broken one on the bench being rebuilt.  Needless to say, that got old fast.  A bunch of folks used to run Super T10s until there was a bad batch of imported gears that caused rebuilt trannies to self-destruct repeatedly.

No affiliation with AutoGear aside from being a very satisfied customer.

rustomatic
rustomatic Reader
1/19/22 4:52 p.m.

How much does it weigh?  As someone not relegated to old-school rules, super light weight would be the only factor in dealing with that mess of shifter rods when they come undone, which they will . . .

Jerry From LA
Jerry From LA SuperDork
1/19/22 5:18 p.m.

GL-4 or GL-5?In other words, does it have "yellow metal" synchros?

frenchyd
frenchyd UltimaDork
1/19/22 9:51 p.m.
Tom1200 said:

$4500 for a race transmission is not outrageous; the extra $500 seems to make sense to me as well.

BUT

Playing devil's advocate and with all due respect to Mr Vogt; how often do trannies actually lock up?

The ones on my Datsun that broke simply shredded the gear; 3rd to be exact. I'm asking because I'm curious about whether or not this is common to V8 vintage production cars. It's not my usual I'm cheap and would rebuild a used box, I really do want to know.

 

 

 

Great point. I've never in 40+ years seen a car come to a screeching halt, locked up.  Really sounds like scare tactics.  To me anyone who stoops to scare tactics to sell their product is a run-run-away, as fast as you can. 
  I've done plenty of rebuilding from a guy who just couldn't shift a manual gear box. But never once had the gearbox frozen.  Oh the gears may be crumbled and main shafts shattered. 
   But unless that person will put his claims in writing, please step back. 

Tom1200
Tom1200 UltraDork
1/19/22 10:27 p.m.

In reply to frenchyd :

I'm not remotely suggesting the supplier is using scare tatics. They are a solid business and they're a well known support of vintage racing. 

Also Tim may also be using the words locked up generically.

The going rate for used Datsun comp boxes is $3000. There is another well known supplier that charges near $7000 for a close ratio box.

Noddaz
Noddaz GRM+ Memberand UberDork
1/20/22 11:10 a.m.

Top tier racing has never been cheap.

gearheadE30
gearheadE30 Dork
1/20/22 11:52 a.m.

One guy's experience killing transmissions: one ripped all the teeth off 3rd gear, which instantly became a kind of grindy neutral. Two ran low on fluid, somehow going from not leaking to completely blowing out the output shaft seal on track. One killed the intermediate shaft bearings and picked up a ton of driveline lash. Caught it before complete failure and limped it home. The other had some internal failure that I can't explain where it lost all the odd numbered gears. Limped it home on 2nd and 4th making terrible noises.

I've only locked up one transmission, which was in a dirt bike. Overshot a jump on an MX track pretty bad and a lot of my weight went into the shift lever because I didn't keep my feet on the pegs. Bent a shift fork, and when I went to shift after recovering, it locked up because it tried to select 2 gears at the same time. Not sure if that's something that can happen in a car transmission, but I assume it could.

GT1Mustang
GT1Mustang New Reader
1/23/22 8:01 p.m.

My GT1/TA car was lacking a trans when I bought it - the 650+ hp 310" Ford Cleveland had broken it (it has also broken a Speedway Engineering 31 spline NASCAR axle). Since it's going to be a track day toy it's getting a TKO600. The one I found was $1,400 lightly used and had been converted to dog gears so no blocked shifts. Having a built in shifter is a cost saver. I do need to get 3 new clutch discs since currently it's set up for the big Ford shaft. I'd wager it'll pass most sanctioning body inspections since it's well hidden by the aluminum panels and I'm using a Hurst handle with 4 speed knob on it.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
1/23/22 8:32 p.m.
rustomatic said:

How much does it weigh?  As someone not relegated to old-school rules, super light weight would be the only factor in dealing with that mess of shifter rods when they come undone, which they will . . .

The shifter rods are really not bad, the main issue is inside the shifter itself.

I never weighed a T10 but they were fairly easy to swap on a lift without a trans jack, one hand holds the trans up and the other one is on the end of the tailshaft to aim the input shaft where it has to go.  When the cases are aluminum and there are only four gears, there isn't much mass.  The real weight is in the scattershield, which I'd kind of want to run.

 

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) SuperDork
1/23/22 8:40 p.m.

I've been wanting to get another Miata so I can install an LS engine and the new Tremec TKK transmission.  It's a T5 on steriods and would be so much fun behind a healthy V8 in a light car.  Dreams.....

 

 

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