The Hydra-Matic Front & Rear Housings compromise a matched set. (Check attached) Is there any type of measurements that a I can perform to insure that the Front & Rear Housings, that I have, are really a matched set? If they are not a match set, is there anything I can do to fix the the problem if there is one? More info at link below: http://chevy.oldcarmanualproject.com/gmc/54hdtmm/54htmm071.htm
The reason for the matched halves of the bellhousing is to be sure that the torus member of the fluid coupling runs concentric to the crankshaft hub. The torus is the part that some uninformed people would call the torque converter (which a Hydra-Matic does not have). You'll need to fabricate a fixture to check the front of the bellhousing when it's bolted to the block by rotating the crankshaft and checking for runout with a dial indicator, then you'll need to bolt the two parts of the housing together, rotate the torus, and check for runout there. At one time, I believe there were offset dowel pins designed to compensate for out of specification dial indicator readings. Very few shops had the equipment or the knowledge to correct an out of spec runout situation, even back when these transmissions were in general use. Since my father was the first man in Nashville Tennessee to work on automatics back in the late 1940's, his shop was the exception to the rule. The checking equipment can be fabricated with a little ingenuity- - - -the skills needed to correct a problem haven't been general knowledge in about 50 years or more! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I was thinking that when the two housing are bolted together. Both the front and rear faces have to be parallel to each other.
Like maybe at the factory, they bolted the two housing together and machined the face of the front housing parallel to the rear housings face. (check attached)
Do you think when the front and rear housings are machined parallel makes them a "Matched Set" ?
illustration According to the illustration it looks like if you bought the flywheel housing, they both came as a housing assembly. Another words, you had to buy the front & rear housings together.
Its probably not good to mismatch housings, otherwise you might run into problems that you might not be able to fix.. What do think?
Parallellism isn't the problem- - - - -radial runout is. Go ahead and guess about it if you choose. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
So what you are saying is, You can use a front housing that came from one truck's engine/trans and a rear housing from another truck's engine/trans.. Just as long you check for runout with a dial indicator.
Yes, that's correct. Later transmissions like the aluminum case Powerglide (1962-up) and the Turbo 350 did away with the 2-piece adapter because there were no bellhousing bolts behind the flywheel to contend with. Then runout became a non-issue. The Dual Range Hydra-Matic was an incredibly precisely machined piece of equipment which was very expensive to produce. That's one reason Rolls-Royce used a slightly modified version of it in their cars under license from GM. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Yes, that is where the procedures are to align the housings and check the flywheel and torus cover runout. Sounds like a pain in the butt.
The GMC Hydra-Matic manual stated that the front & rear flywheel housings compromise a "matched set". I took "matched set" meant that the front & rear flywheel housings were somehow married to each other, from the factory.. Which is not the case.
The front and rear housings were matched, and serial numbered together on the assembly line. The tools used above were required to align replacement parts in case the matched assemblies got separated or one was damaged in some way. Yes, it's a royal pain to get mismatched parts to work well together. Rapid wear and vibration was usually the result of trying to force-match front and rear sections without going through the alignment procedure. I grew up around a shop where they did things the right way the first time. Until I started working in other shops, I didn't realize how much half-donkey work was done on a routine basis! 60+ years in the business hasn't changed my opinion of a lot of so-called "mechanics"! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The assembly line worker must of dial indicated the: Torus cover runout Flywheel runout Rear Flywheel housing bore runout Rear Flywheel housing face runout to the engine block that the Hydramatic trans. was going to be mated to.
When the all the dial indicator readings were within specifications, the assembly line worker stamped the engine serial number onto the plate that is on the rear flywheel housing. After all of the above was done, the front and rear flywheel housings, could then be called a "Matched Set".
This is cast into the rear flywheel house: THIS HOUSING MUST REMAIN WITH THIS ENGINE
I'm assuming HOUSING means front & rear housings.
The 2nd attached photo shows the front side of the front flywheel housing. Would anyone know what holes were used for the dowel pins? I think there are three dowel pins used.
