[DeTomaso] ZF Gear Ratio information

[ProvaMo.com]

I've added Mike's information to the ProvaMo ZF page.

Thanks Mike!

Chuck


> Only 1st,3rd, and 4th are different.  The fifth gear and final drive are 
> the same for Dash 1 and 2 so there should not be any difference at speed.
> All ratios are listed on the RBT website.
> 

Uh...no.   That's completely wrong. :<(

The ratios listed on the RBT site are what Lloyd CURRENTLY offers in his 
new-production gearboxes, which has no bearing whatsoever on what these were
built 
with 35-40 years ago.

Many early Panteras were built using leftover Mangusta gearboxes, which were

converted to Pantera specification by ZF.   Their gear ratios were:

1st:   2.42
2nd:   1.47
3rd:   1.09
4th:   0.958
5th:   0.846
Reverse:   2.86
Final drive:   4.22:1

>From the fall of 1971 (or so), they were:

1st:   2.23
2nd:   1.47
3rd:   1.041
4th:   0.846
5th:   0.705
Reverse:   2.87
Final drive:   4.22:1

So, the early Pantera 5th gear was the same as the later Pantera 4th gear 
(and many believe the later Pantera 5th gear is still too short!)

> I went to check my 5th gear (I have an early 71 #1343) and the plate
states 
0.84 despite the RBT site for a Dash-1 stating .705.  

>>>See above.   You obviously have an original, untouched early or 
intermediate Dash-1 gearbox.

 >Are there several different models or styles by date for the Dash-1 family

and what is the Dash-0? 

>>>Yes, there were several different variations on the gearboxes during the 
early days of production, due to the fact that much of the initial build was

comprised of leftover Mangusta gearboxes.

(The Dash-0 gearbox was the initial ZF gearbox that ZF designed and built 
especially for the Ford GT40 program, starting in late 1964/early 1965).

The first Pantera prototypes were issued gearboxes with the part number 1031

001 056.   Only two of these gearboxes were built in December 1969; they had

the low gearing.   These were for the first two show cars.

The next gearbox was the 1031 001 059.   Ten of these gearboxes were ordered

for delivery in the first week of March, 1970 for use in the initial 
testing/evaluation prototypes.   In fact ZF had to build 13 gearboxes to
fill this 
initial order because three of them had to be scrapped due to bad input
shafts 
(they were hand-making the input shafts then).

The next cars were issued transaxles with part number 1031 001 060.   
Initially only 60 of these gearboxes were to be built, but given ZF's parts
on-hand, 
this order was increased to 80; delivery of the first 40 was scheduled for 
August 14th, 1970 with the remaining 40 by the end of that month.   These
were 
made using surplus existing Mangusta gearboxes that were shipped from De
Tomaso 
in Italy back to ZF in Germany for conversion for Pantera use.   

The side flanges on the differential were made of aluminum instead of steel 
castings; these aluminum sideplates are very rare, especially in light of
the 
fact that due to the tail mounting of the transaxle, they were subject to 
stress and frequently cracked under load.   These were actually leftover
GT40 
(Dash-0) gearbox parts.   Although the original scheme was to make them all
this 
way, after quickly experiencing failures, they went back to using cast iron.

Note:   Mangusta production was scheduled to be phased out from January to 
March, 1971, but in fact at least a few cars were apparently built in 1971 
(including all ten right-hand-drive Mangustas), so De Tomaso had to keep
some 
Mangusta gearboxes on-hand to fulfill orders.   Evidently they had purchased
a 
bunch of gearboxes for the Mangusta program up-front, and calculated that
not all 
of them would be necessary once the Pantera program got going, so a
percentage 
of them were recycled for Pantera use.

Starting in September 1970, ZF shipped yet another variation of the gearbox,

this one part number 1031 001 061.   The original contract was for 451 of
them 
to be produced, but in light of the increased production of the 060 version,

the order was reduced to 411.   These Dash-1 gearboxes were to be built with

the later gearing (i.e. .846 4th, and .705 5th).

These were all variations of the Dash-1 gearbox.   

The finalized, definitive Pantera-spec gearbox was the Dash-2; this was part

number 1031 002 001.   De Tomaso placed an order for 720 of these gearboxes
on 
Feb 23, 1970; in July of that year, ZF promised that they would start 
delivering them at the end of March/early April 1971.   

Ford had grand ambitions for the Pantera program, projecting sales of 5000 
cars per year, which would have required ZF to deliver more than 400
gearboxes 
per month.   They had issued a request for proposal to ZF for the supply of
a 
total of 15,000 gearboxes over the three-year period 1971-1973.   ZF knew
that 
they could not fulfill this requirement and were very public about that
fact, 
so in March, 1970, two representatives from Ford traveled to Israel (!) and 
met with representatives from a company called Ashot-Ashkelon.   There they
drew 
up a deal whereby the Israeli company would manufacture the gears and 
differential parts, which would then be shipped to Germany for ZF who would
install 
them in the gearboxes.

By October of 1970, it became apparent that the sales projections were
rather 
optimistic, to say the least.   At the same time, ZF upped their production 
projections based upon improved performance of their local gear-producing 
subcontractors, and determined that they could build at least 60 gearboxes a
month 
in-house.   So the deal with Ashot-Ashkelon was scrapped.   

However, there were some political considerations that needed attention.   
The deal with Ashot came about at least partly because of a tariff system in

place in Israel which limited imports by Ford-Israel.   Local Content
Credits had 
been negotiated, with the result that if Ashot produced parts for some 400
ZF 
gearboxes a month under the auspices of a Ford project, Ford-Israel would be

allowed to import an additional 3000-4000 Ford-Europe cars (Escort etc.)
into 
Israel.   When the Pantera program sales projections (and thus ZF gearbox 
production projections) scaled back, Ford and ZF quickly renegotiated the 
contract, shifting the proposed Pantera gear production towards other ZF
projects, as 
well as parts to be supplied to Ford-Europe and Ford-USA Truck Operations, 
which qualified equally for the Local Content Credits.

 >Lloyd did say that a decent Dash-1 was worth 8-9 grand and that they were 
sturdier than the Dash-2 models though.   I don't think you can buy the
taller 
5th gear for these early gear boxes or if you can it is not as simple as you

might think.  I was told it may be cheaper to swap for a Dash-2 than to try
to 
change only one gear. 

>>>Well, it depends on what you're trying to do.   Also, Dash-2 gearboxes 
have now become quite popular due to the recent explosion in the GT40
replica 
market, so even finding a Dash-2 gearbox might be next to impossible.

 >I looked at changing the final drive ratio but was afraid it would 
drastically affect take off unless I put in a massive stroker.  Anyone
changed final 
drive with a normal engine and been happy with it?

>>>You haven't phrased your question properly.   The real question is, "Has 
anybody changed the final drive with a normal engine AND the early, Mangusta

gearing?"   The answer is probably no.

My spitball analysis is that you would be best off switching to a 3.77 ring 
and pinion.   That, coupled with your ridiculously low internal gearing,
would 
probably roughly equate to what the later gearboxes had with the taller 
gearing and the 4.22 ring and pinion.

In fact, a few moments spent with the ZF gear calculator Excel spreadsheet
on 
the www.panteraplace.com site reveals the following:

With the later gearing of the Dash-2 gearbox, with a 4.22 ring and pinion, 
the speed in gears per 1000 rpm works out to:

8      13    18     22     26

While with your gearing and a 3.77 ring and pinion, the speed in gears per 
1000 rpm works out to:

9     14     19     22     25

Pretty damn close!   If you can fit a 3.77 ring and pinion into your gearbox

(and I'm fairly certain you can), then for sure that is the way to go.

>The main issue with early 71 cars I have experienced is when you order
parts 
for a 71 they may not fit. For example you can't put camber locks on the 
front without a lot of changing things up as early 71 models do not accept
shims 
and glass/trim pieces are hard to come by.  However, at Wilkinsons or
Quella's 
if you tell them exactly what car you have they are very good about knowing 
all these little details. 

>>>Exactly true.   You have to be VERY specific however, when you have an 
early car like yours, giving them the VIN, plus any other details that might
be 
relevant.   Having detailed familiarity with your own car will be helpful 
before placing an order; they might ask you for a specific measurement (such
as on 
the front A-arms) for example.

Many early Panteras had their gearboxes switched out from Dash-1 to Dash-2 
under warranty.   This was a total scam pulled by the Ford dealers.   Ford 
somehow got it into their mind that there was a defect in the early
gearboxes, when 
in fact the only problem was caused by poor clutch adjustment.   Ford issued

a bulletin to the dealers and said they would pay them to replace any 'bad' 
gearbox under warranty.

Dealers instantly lit up and saw dollar signs, because this was a big job
and 
they got paid well for it.   So, every Pantera that rolled through the 
dealership for a routine service was diagnosed with a 'bad' gearbox.   The
service 
manager would tell the owner, "Hey, Ford has produced a new, better 
transmission and we will replace your existing one for free.   Would you
like one?"   Of 
course every owner said yes.

So, perfectly good Dash-1 gearboxes were pulled out and replaced with Dash-2

units, and Ford wound up getting stuck with the bill each time.   Many years

ago, I spoke with a service tech who worked at a big L-M dealership in Long 
Beach, I think.   He said that they did this as a matter of course,
sometimes not 
even telling the customer about it beforehand.   They would then file a
claim 
with Ford and get reimbursed for all the labor costs.

He said that there was a stack of 30-40 Dash-1 gearboxes out behind the 
dealership at one point, and then one day they were all just whisked away to
the 
crusher. :<(

That's why it's not very common to find early cars like yours with original,

low-ratio gearboxes.

Mike (who had to dig WAY deep into his De Tomaso history archives, reading 
individual memos, reports, and purchase orders between Ray Geddes, ZF, the 
Israeli Minister of Finance, Henry Ford, Alejandro De Tomaso, as well as
various 
Ford engineers involved in the Pantera program, to get all this data
together...
.)


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