Re: [ihc] RE: Automatically David

["ken.dunnington" <ken.dunnington@xxxxxxxxx>]

Hydramatics are very strong.  I have one in my '55 Pontiac with a
high-perf 380.  There are several versions but the basic one is very
common.  It was used in GM products, Bentleys, tanks, large trucks,
etc.  They do not have a torque converter, only a fluid coupling.
Thus the four speeds, first gear is a very short, get the vehicle
moving gear and then second is shifted into.  They are direct drive
fourth.  Almost always uncooled, so they transplant well due to not
needing external cooler.  Basically, keep fluid in them and they will
take a huge amount of punishment and keep on going.  And Ryan is
correct that they allow the vehicle to be push started.  They have two
pumps, one driven off input, one off output.  This is what allows the
push/pull start.  One aspect I'm not too fond of is the fluid
coupling.  It is a two piece affair.  The front half is the flywheel,
which is bolted to the back half using 36 bolts around the perimeter,
with a gasket in between.  I had the joy of doing this and then it
leaking.  Then doing it again with still a small leak.  Third time was
the charm.  Trans case is cast iron/steel so it is VERY heavy.

Ken

JG> Early R series autos were Hydramatics, then the Hydramatic factory burnt
JG> down :(

JG> S series had Detroit Gear/Borg Warner autos. Plenty stout, variants of which
JG> were used behind everything up to and including the 392 into '72. All of
JG> them shifted *automatically* when put in 'D', no manual shifting required.
JG> There was a 'dual range' version, with D1(1st to 2nd gear) and D2(2nd to 3rd
JG> gear) shift positions. A version with a lockup converter had a Sales
JG> Engineering brochure published, AFAIK no one's documented any actual
JG> installations.

JG> Jim

JG> From: David Raistrick <keen@domain.elided>
JG> Subject: [ihc] 50's 120 automatics?

JG> Hey guys.

JG> Just browsing the ads and saw this one:

JG> http://www.collectorcartraderonline.com/caddetail.html?/ad-cache/10/4/0/6581
JG> 3940.htm

JG> 3/4 ton with an automatic.  I'm not a particular fan of automatics, but
JG> I'm curious how solid these old autos are?  Any thoughts on them?