Tim Suddard
Tim Suddard Publisher
1/19/22 10:57 a.m.
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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 …

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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) GRM+ Memberand 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.....

 

 

Tim Suddard
Tim Suddard Publisher
6/7/22 7:09 a.m.

In reply to Tom1200 :

The problem is that if it only locks up once, it could hurt you, someone else, or at least the car.

Tim Suddard
Tim Suddard Publisher
6/7/22 7:11 a.m.

In reply to frenchyd :

I did not buy the transmission from Cobra Automotive. They just told me what they buy and why. They learned the hard way, that this is a place to spend money. Curt Vogt of Cobra Automotive has been very careful in advising us on  where to spend money and where not to.

Tim Suddard
Tim Suddard Publisher
6/7/22 7:12 a.m.

In reply to rustomatic :

I don't think this box is any lighter than any other top loader.

frenchyd
frenchyd MegaDork
6/7/22 8:03 a.m.
Pete. (l33t FS) said:
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.

 

But both the T10 and the Muncie M22 were only good for a weekend or two.  The Muncie the case spread and the T10 the gears went.  
   As long as I could get new cases it was a short job to change over.  But the T10 you had to magnaflux the gears to see where the cracks were.  That took hours to take apart clean and magnaflux. Decide what to replace and what to keep.  Then replace. 
  On the M22  if you were really pressed you could dimple around the bearing holes. And probably get another weekend  out of it.  
   We were building Small blocks. It would get real dicey with a big block.  In fact the serious big block guys would  change it out every night. 

racerfink
racerfink UltraDork
6/7/22 9:04 a.m.

In the Spec Miata world, some guys go through a trans about every four or five sessions.  My friend Jeff usually spends at least one day a week at his race shop rebuilding Miata trans.  My SM had a bone stock gearbox with 196k on it when I converted the car, and had 198k on it when I sold it 8 years later.  Some people are just much rougher on cars than others, I've found.

Tom1200
Tom1200 UltraDork
6/7/22 11:33 a.m.
Tim Suddard said:

In reply to Tom1200 :

The problem is that if it only locks up once, it could hurt you, someone else, or at least the car.

I'll take this answer to mean: it rarely happens but it can happen so why take the changes...............got it.

APEowner
APEowner GRM+ Memberand SuperDork
6/7/22 11:54 a.m.

I've never had a race car transmission lock up but I did almost run over a vintage Corvette that had theirs lock up.  It was an exciting time for everyone.

I did once have a U-Haul truck transmission lock up when I was coming down a mountain in a snow storm in the middle of the night.  I was downshifting from third to second and it made kind of a clunk when it went into second and locked the rear tires.  It tried to spin around sideways but I was able to keep the rear of the truck more or less behind the front.  When it came to a stop is was right in the middle of the road where it sat for about three hours until the wrecker was able to get to me.

frenchyd
frenchyd MegaDork
6/7/22 2:07 p.m.

In reply to racerfink :

Absolutely.  It's more the driver than the transmission. 

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