DeTomaso Mailing List: April 1997, Message #96
     



From: MikeLDrew@aol.com

Subject: Re:  Gearbox history

Date: Mon, 14 Apr 1997 02:24:10 -0400 (EDT)



All,



Jim Firanzi wrote:



>Where in year group or serial number do the 'early' ZF's become 'later' and

therefore less expensive to rebuild?  Are we talking about -1 vs. -2 boxes,

or

are all rear mounted ZFs considered 'early'?



>>>  Mangusta-style Dash-1 ZF's with different (higher numerically) gear

ratios were used in the first Panteras.  I don't know when they were phased

out in favor of the Dash-2, but it was early in '71 for sure; I'd expect only

100-200 cars came with the early box (just a guess)



Easy way to quickly recognize the difference:  They use a different bolt

pattern where they mate to the bell housing, and thus a different bell

housing.  Dash-2 boxes have a single bolt in the top center (12 o'clock) and

one at 10 and 2 o'clock; earlier Dash-1 boxes only have the two bolts at 10

and 2 o'clock.



Don't know if any Dash-2 boxes came with the early-style rear mount, but I

suspect not.



Jim, your car has a Dash-2; although it's marked as being a January '72 car,

in fact it's built to 71 specs (flat bumpers, flat decklid, etc.) and should

technically be considered a late '71 car.  I don't remember if you've got

side mounts or a tail mount, but if you're going to do any serious driving,

you should side-mount it.



Note:  there were several inaccuracies in the ZF article that ran in the last

POCA newsletter.  All Panteras with Dash-2 gearboxes came to this country

with 4:22 rear ends, which would yield 159 mph at 6000 rpm.  None ever came

with 3:77 except perhaps GT5's, and that would have been special order since

4:22 was the standard ratio even for those.  I honestly don't know about

Dash-1 ratios, although I'm under the impression they too used a 4:22 and the

reason for the lower gearing and thus lower top speed was different ratios

for the five gears themselves.



I'm sitting in a hotel room and thus don't have any of my reference materials

available.  I know that the earliest pushbutton cars tested in U.S. magazines

were fitted with Dash-2 boxes, or rather, Ford issued the specs for the

Dash-2 which were printed in the spec sheet even if the car itself had a

Dash-1 box!  I seem to recall a chart or box in the Wally Wyss book that lays

out the differences between Dash-1 and -2 Pantera boxes gear ratios; anyone

care to look it up and share with us?  Or, look in the Brooklands books for

Mangusta road tests and see if the gear ratios listed are different from the

later Pantera ratios?



GT-40's used neither the Dash-1 nor the Dash-2 ZF; they originally used a

Colotti 4-speed which was junk; that's why they blew up in such spectacular

fashion at their first year at Le Mans.  Ford never really got a grip on the

gearbox problem; next time out, they had Kar-Kraft (a wholly-owned Ford

subsidiary specializing in, well, special stuff) fabricate dedicated

gearboxes from scratch, because the much-vaunted ZF hadn't reached production

yet and Ford couldn't wait any longer.  The gears weren't heat-treated

properly, and the cars all retired with blown gearboxes.  The later

427-powered Mark II's used this box (now sorted out) and drove to victory in

'66.



Eventually GT-40's started being fitted with ZF five-speeds.  They actually

used the first version of this transmission, now called the Dash-0 (zero) to

differentiate them from their later cousins but originally just called

5DS/25.  They differ from the later boxes in virtually all respects; for one

thing, they used very noisy straight-cut gears and could be shifted easily

without using the clutch.  GT-40 gearboxes cost a BUNCH of money; hardly any

parts out there anymore either, even for the Dash-0 ZF.  For these reasons,

quite a few GT-40 owners have converted to Dash-2 gearboxes, possibly the

source for the confusion in the article.



Finally, for the overwhelming majority of his times at the Silver State,

Junior Wilson was running a Dash-1, only because his car was originally an

early '71 car and that's what he had in it.  Come to think of it, he DNF'ed a

few years ago when the car became airborne over a bump, the motor wrapped to

10,000 rpm, and when the car suddenly landed, it twisted the input shaft and

fragged the box, so Jack's probably right, he's probably running a Dash-2

now.



Still, the important thing to remember is that there's nothing inherently

WRONG with the Dash-1 (although the Dash-2 is probably a better box), and if

you're running one in your car, as long as you look after it you should be

fine.  But only a fool would rebuild one in a driver Pantera; a basic rebuild

costs more than double that of a Dash-2 rebuild.  Perhaps worthwhile for an

originality freak with a bone-stock early Pantera, but if it's been modified

in any way, the owner might as well just buy a replacement gearbox (Dash-2)

already rebuilt and just bolt it in; it's less expensive, and it's a better

long-term fix.



As Jack said in his article, the best way to do it is to fabricate mounts to

accept the standard two-eared side mount system.  Somehow, I don't think it's

as complicated as he made it out to be for most cars; when this issue first

was raised, I did a little poking around under several cars, and thought the

side mounts could be mounted to the chassis fairly easily, only requiring two

pieces of flat steel to be welded onto the existing chassis member to accept

the mount.  Jack seems to think this member itself would be missing.  Perhaps

this is the case on VERY early Panteras; later ones (even with the

tail-mounted gearbox) had the chassis member in place; I know because the car

I looked at was configured this way.



Wow.  It's midnight.  I gotta get a life.



Mike