> John; > The Packard automatic transmission was called an "Ultramatic" and it was an > in house made unit. The early Borg Warner automatics, with the mechanical > lockup, were developed jointly with Studebaker so they were hence called the > "Studebaker Automatic" in the American manuals. Studebaker used these > transmissions between late 1950 and 1956 after which they switched to > another Borg Warner automatic, that they called a "Flightomatic". The same > transmission was also used in some Ford products which made it cheaper to > use then the "Studebaker Automatic" out of straight economy of scale. I have > heard rumors that Borg Warner did take the "Studebaker Automatic" to Europe > after Studebaker abandoned it but I had no confirmation that Jaguar used > them, especially as early as 1953. This is good information to know as early > fifties Studebaker owners apparently have a hard time finding parts for > these units. Well, interestingly enough Jaguar did use them - I have got one sitting in my garage, and I also have the original repair manual. Almost all of the Jaguar Mark VII Saloon export models destined for the US had the B-W automatic. UK models and most other export models had a manual four-speed. The automatic cars had an 'Automatic' logo in script on the boot (trunk) lid. This tranny is 50 years old, has no leaks, and still shifts crisply and smoothly. Very refined. The design was ahead of its time, and handled the power and weight of the car (this was the fastest sedan available at the time - over 100 mph out of the box and yes, they were raced). Unlike the later B-W 66 (IIRC) boxes in the XJ6 sedans that could not handle the weight of the car and had poor ratios, too. It sounds like this is either the same Studebaker transmission, or a close relative. Obviously, it is designed to bolt to a Jag XK engine block. I have the original build sheet for my Jag from the Jaguar Mother Ship in Coventry, and it states that my car was originally fitted with this B-W automatic. In the mid-50s, the same B-W box was still fitted with two modifications: it would shift thru all 3 gears in 'D' (mine starts in 2nd in 'D' and shifts to high; you only get 1st when in L range) and they added an automatic anti-creep feature (line lock? :] ) so you did not have to keep your foot on the brake when stopped and in gear. The quadrant on this tranny is PNDLR, like the early GM 4 speed fluid drive hydramatics (PNDSL) or early 60s GM Slim-Jims (PNDLR), but unlike todays standard of PRNDL. > As for the transmission in your Jaguar not having a cooler I doubt if that > was the reason for the mechanical lockup in those units as Studebaker > promoted this feature for the fuel economy aspect. I am not aware of Jaguar hyping this feature for fuel economy. In fact, the owners manual is completely silent on the topic. I only found out about it from reading the repair manual - and there it is, a friction clutch in between the flex plate and the torque converter. Because Jag said nothing about it, and because the Jags of the era had overheating problems, and because a slipping torque converter adds heat, and because the tranny was air-cooled - this was my conclusion. I might be wrong. > P.S The technical term for a Gyromatic, Prestomatic, etc, is an M6 semi > automatic, at least according to my manual. That's probably the best way for us to refer to them, too! Thanks for that info. There are some nice repair manuals that explain the operation of the M6 on the Imperial web site. John