The Stovebolt Site Forums The Shop Area Driveline 1955/2 Hydramatic Adjustments

Good Friends,
I am needing to adjust linkages and bands on a 55 hydra. I don't have the special tools of which they speak in the manuals. Nor do I have the measurements for these adjustments to enable me to make them, the tools or the adjustments. Do any of you fine folks have these tools or the measurements for these adjustments? Or, can yall direct me to someone who has the expertise with this particular piece to guide me thru this process. Any and all advise is welcome. I thank yall for your support.
dgerth

The only linkage that would need adjusting would be the throttle pressure, and it's sort of a "move and try" situation until you get the smoothest shift without RPM flare-up between speeds. The Dual Range transmission is VERY sensitive on throttle pressure adjustment. The 1-2 shift happens almost as soon as the vehicle starts moving, probably at less than 10 MPH. Is your transmission actually a 55 or later model? The 55-up Hydramatics only have one band adjustment accessible without dropping the pan, while 54 and earlier has two adjusters on the outside of the case. The 55's need the factory tool to do the internal front band adjustment.

The rear band on the 55-up is adjusted by loosening the adjuster several turns, then putting the gear selector in LOW with the parking brake set firmly, and tightening the band until it just touches the drum. (you can feel it get snug) Then go to Neutral, and count the number of clockwise turns until it gets snug again. Turn back (counterclockwise) 1/3 the number of turns which were needed to tighten the band in the neutral position. Confirm that the adjuster is tight when in the low position, and loose in Neutral. If so, tighten the lock nut. I seem to remember the front band adjustment involved using a 1/4" spacer between the adjusting screw and the band, and tightening to 72 inch-pounds before tightening the lock nut, but it's been a very long time since I was inside a dual range transmission. I remember Dad using a Craftsman 7/16" open-end wrench as his "special adjusting tool", as it was exactly 1/4" thick! He rebuilt thousands of transmissions in Nashville in the 1950's and 60's!
Jerry

Jerry,
Thanks for the response. I do believe that this transmission is original as I bought it from the original owner. It was the 13th truck to come off the LA line in 1955. This is my 1st Hydra and thus new ground for me to plow. I got the above data from the #'s on this site.
tks again,
dg

OOPS! Forgot to mention, those adjustments are done with the engine running! For safety, it's wise to jack up at least one rear wheel, to keep from getting run over in case the parking brake slips while you're under there adjusting with the vehicle in gear!
Jerry