Tranny fluid change on 1955 oldsmobile


#1

I drained the tranny fluid out of my 55 Oldsmobile and I need to know how much is supposed to drain out without draining the torque converter so I don’t overfill. Thanks.


#2

Doesn’t the transmission have a dipstick?

Service manuals typically have several capacities listed

For example . . .

amount if you just drain the pan

amount if you drain the pan, and replace the filter

amount if you do a total overhaul

and so forth

I’d be less concerned with how much came, out, versus getting it up the proper mark on the dipstick, when you’ve got fresh fluid in, and it’s up to proper operating temperature

The dipstick always trumps the capacity listed in the book

The capacity listed in the book is a pretty good approximation, but not always 100% accurate. Sometimes you need a little more than what’s listed in the book, sometimes you need a little less

If you don’t know how much you’re supposed to put in, start slowly. Add say 2 or 3 quarts, then start the engine. Go through the gears and let fluid circulate. Check again after a minute. Add as needed, until you’re at the full cold mark. Drive the car for a few miles. Then check again, and fill as needed, until you reach the full hot mark

This advice is for an automatic transmission in general

I don’t know if there’s anything special and/or different about YOUR transmission


#3

Why didn’t you drain the torque converter, didn’t it have a drain plug/


#4

@Guggis2011

Was it at the proper level before you drained it?

When I do transmission fluid replacement (I often use a Liqui-Vac), I first check for proper level, drain (without spilling), measure what came out, refill with that amount of new fluid.

I have factory shop manuals and Owner’s manuals for all my cars and they give specs, but nothing is as accurate as the method I’ve outlined, above.

CSA


#5

In my Motors book, in the Olds section, it says the capacity is 11 quarts but I’m sure that is the total capacity. In the Hydra-matic section it says to add 8 quarts then run the engine at high idle in neutral for 1 1/2 minutes, reduce the idle and add additional fluid to bring the level to 1/4" below full on the dip stick. That sounds about right to me.

Edit: There are two hydra-matics listed, a dual coupling and a single coupling. No info on which is used where. The above is for the newer dual coupling. For the single coupling, the info is the same except add 9 1/2 quarts the run it for 1 1/2 minutes at high idle and fill it exactly to the full line.

Good luck. You need to get a service manual.


#6

Chilton indicates that the 1955 Oldsmobile has the Dual Range Hydramatic which is drained by removing the dipstick tube and a 7/16" pipe plug from the torque converter. They instruct to add 8 quarts of ATF and start the engine and add until 1/4" below the full mark while cold. It would have been helpfull to measure the amount drained to replace it with an equal amount but the horse is out of the barn now so you must shoot from the hip or start over.


#7

This transmission has no pan to remove . . . ?!


#8

I’m ashamed of myself but searching the memory banks, I can’t recall ever changing the transmission fluid in my 59 Pontiac. I do know I had the level checked at least once back in my youth because I remember the old guy having me run it around first to warm it up. That’s how I learned that. Kids. How far we have come in 50 years. Now I’m the old guy trying to tell the kids to change the fluid.


#9

Not that I would bet my last dollar on any shop manual’s information the old Chilton indicates that the 1955 Olds used the Dual Range and the 1956 used the Dual Coupling. The OP would do well to buy every piece of techical data available on the old car to get it in order.


#10

Nobody’s answered my question yet . . .

Does OP’s transmission have a pan?

Yes or no?


#11

OK, OK. One of the things I understand least is transmissions. I believe the dual range and dual coupling are the same since it has something to do with the elimination of the bands and I think going from 1-2 to 3-4 with a coupling instead but I don’t know. Motors has a picture of the dual coupling that clearly has a pan. There is no picture for the single coupling so don’t know. The draining procedure though says to remove the plug from the oil pan AND the flywheel after the cover is removed. So two plugs for the pan and what we now call the torque converter I think.


#12

Why? Just pass on your experience to the kids:grin:. They will love it, no transmission fluid changes ever!!


#13

Thanks for answering the question about the pan

This old transmission from 1955 has 4 gear ratios . . . ?!

That would make it VERY advanced for 1955


#14

“Now I’m the old guy trying to tell the kids to change the fluid.”

HEY!! Get off my lawn!
CSA


#15

Actually @Bing the Dual Range Hyrdamatic came out in 1939 for 1940 models of Cadillac and Oldsmobile. Nash bought them from GM in the early '50s.


#16

It is correct that the Hydramatic was available in 1940, but I thought it was only an option on the Oldsmobile. The transmission did have four forward speeds. The “Dual Range” came along in 1952. There were two “Drive” positions. One position locked it out of fourth for city driving. However, if one exceeded 70 mph in this range, it would go into fourth gear. This city range was designated with an “S” on the Oldsmobile shift quadrant. There were four speeds partly because there wasn’t a torque converter, but a fluid coupling. The difference is that a.fluid.coupling does not multiply torque as the torque converter does. The Hydramatic was not.only used in the Oldsmobile, Pontiac, and Cadillac, but was available in the GMC pickup starting in 1953 and the Chevrolet pickup starting in 1954. The Chevrolet and Buick cars used a completely different type of automatic transmission that depended on a torque converter. Nash, Hudson, Kaiser also uses the GM Hydramatic and surprisingly, it was used by Lincoln beginning in mid 1949. To me, the argument between the Hydramatic with its fluid coupling and four speeds as opposed to the automatic transmissions on other makes with fewer speeds but a torque converter is analogous to today’s discussion between a mulri-speed automatic and a CVT.