[AT] ATIS Holifday Charity Auction

[Steve W.]

The problem is similar to many other marine items folks try to use on
the street, and vice-versa. Marine transmissions see constant torque
loading for the most part. Street transmissions on the other hand have
constantly changing loads. That was what caused the problems with the ZF
units. They were fine in trucks and cars that were not really used
heavily. Most of the ones used in trucks that actually hauled real loads
or towed a lot failed because of the shock loading of the internals.  GM
then ordered heavier units for the next generation of trucks. The real
heavy duty transmission to use in a GM is the SM456 with granny low for
trucks up to about 88. For newer trucks and for folks who are ordering
new the manual of choice is the NV4500 5 speed. It is actually a 4 speed
with OD in the 5th hole. The SM 456 is cast iron and is HEAVY duty. BUT
you don't have a lot of gear choice. Of course if you could pair it with
a 2 speed rear it is a great rig.

I was actually looking at a 50's cabover GMC and thought about a 383
stroker motor built for pulling with the SM456 behind it and a 2 speed
Rockwell in the rear. Maybe toss a gear venders overdrive in there and
putting a 15 foot bed on it and it would be a great tractor hauler and
get better mileage. The cabover is up for sale about 10 miles away.
Needs work but looks to be complete and not badly beat up, if anyone is
interested I could get a few shots of it and send them to you.

Steve Williams
Near Cooperstown NY


----- Original Message ----- 
From: "charlie hill" <chill8 at cox.net>
To: "Antique tractor email discussion group"
<at at lists.antique-tractor.com>
Sent: Friday, December 03, 2004 5:27 PM
Subject: Re: Re: [AT] ATIS Holifday Charity Auction


> That is interesting in that ZF is probably the world leader in Marine
(boat)
> transmissions and clutches.  There stuff is usually excellent.
>
> Charlie
> ----- Original Message ----- 
> From: "Steve W." <falcon at telenet.net>
> To: "Antique tractor email discussion group"
<at at lists.antique-tractor.com>
> Sent: Friday, December 03, 2004 1:25 PM
> Subject: Re: Re: [AT] ATIS Holifday Charity Auction
>
>
> > Yep those transmissions were German made ZF units. Marginal for use
in a
> > car and VERY poor for use in a truck that actually was used as a
truck.
> > The main reason for them was the fact that GM closed down the
Saginaw
> > plant and started buying manual trans from other suppliers. Now if
you
> > could find one of the old cast iron monsters it would bolt in
without
> > problem.
> > Steve Williams
> > Near Cooperstown NY
> >
> >
> > ----- Original Message ----- 
> > From: "Grant Brians" <gbrians at hollinet.com>
> > To: "Antique tractor email discussion group"
> > <at at lists.antique-tractor.com>
> > Sent: Friday, December 03, 2004 10:00 AM
> > Subject: Re: Re: [AT] ATIS Holifday Charity Auction
> >
> >
> >> Actually the 1980's GM 4 speed truck tranny's are notorious for
> >> self-destruction. Everyone I know locally with one had to replace
it
> > at
> >> least once in the first 100K miles - one friend replaced his three
> > times,
> >> the first time under warranty! His case was not one of abuse, just
> > use. The
> >> reason is that sometime in the late 70's (date is hazy) GM
> > "re-engineered"
> >> the manual transmissions to save weight and money.... They ended up
> > making
> >> them too weak as a result, with the consequent explosion of repairs
> > and
> >> replacements. Shaft breakage, premature bearing failure and case
> > cracking
> >> all became common. This was one of the reasons for GM's precipitous
> >> commercial track sales decline in the 80's. Additionally it
cemented
> > the
> >> reputation of Ford for reliable light duty trucks because Ford kept
> > the
> >> heavy duty components in theirs.
> >>     Having said all of the above, GM has returned to better Trannys
> >> since....
> >>         Grant Brians
> >>         Hollister California
> >> ----- Original Message ----- 
> >> From: "Jim and Lyn Evans" <jevans at evanstoys.com>
> >> To: "'Antique tractor email discussion group'"
> >> <at at lists.antique-tractor.com>
> >> Sent: Friday, December 03, 2004 4:04 AM
> >> Subject: RE: Re: [AT] ATIS Holifday Charity Auction
> >>
> >>
> >> > Those 4 speeds were just about bulletproof (I thought)  What did
you
> > tear
> >> up
> >> > to warrant a transmission replacement?
> >> >
> >> > Jim
> >>
> >> _______________________________________________
> >> AT mailing list
> >> http://www.antique-tractor.com/mailman/listinfo/at
> >>
> >
> > _______________________________________________
> > AT mailing list
> > http://www.antique-tractor.com/mailman/listinfo/at
>
>
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at
>