maineolds

Thanks to the help I've received from many here, I was able to go for my FIRST real drive in the 1949 Olds 88 I've been nursing back to life. It spent the last 30 years or so of its life in various car collections and museums. Its had less than 40 miles driven in all that time. Crazy! Anyway, the engine is running super smooth, the steering is loosening up (it was literally frozen with no fluid in the box). The electrical systems are back and working properly but... The Hydra-Matic trans is down shifting very hard just before coming to a stop. I've read in the service manual that it's shifting from 3 to 1st by design, but how much of a THUD should I expect with this? The transmission has 30,000 original miles and I've drained and replaced the fluid (including fluid from the Taurus drive).
I honestly just don't know what this SHOULD shift like. It shifts awesome going up. Every shift is solid. But coming down, just before getting to a stop it SOMETIMES just slams. Kind of like a fat guy that can't stop his weight after running to fast!
What do you think? I'm considering changing the fluid again. I know the fluid that was in there was over 30 years old.

Tedd Thompson

Have you tried to adjust the long rod that goes from the carb linkage to the transmission?. That may be out of adjustment and cause the transmission to search for the gear selector that is not where it should be. Adjust a little at a time maybe 1/8 turn max.

If skipping first and starting in second gear is a problem (may be related) there is a sticky that describes the fix at the top of this forum, good information found in the quest for the answer. Let us know what you find out.... Tedd

maineolds

I’ll look into that. It shifts perfect going up and perfect going down till that last drop at low speed. Then it hits like a dump truck dropping a load. My engine rpm is between 400-450. I don’t think it’s an RPM issue, but it may be. I’ll examine all the linkage going from the carb to the trans. I’m hesitant to change the length of a rod since it shifts spot on

Ozzie

I don't have the 1949 Oldsmobile shop manual, but since you do look in it and see what it says concerning rough downshifts and how the link to the throttle should be adjusted. My '55 shifts down smoothly. It can be felt, but it's not rough. I'm also wondering if it could be a matter of band adjustment. I'm also wondering if it changed any when you did the initial fluid change.

redoldsman

It is not uncommon for the old hydra-matics to downshift pretty hard into first gear. Tedd is suggesting the same thing I would try. It is never going to be at a point where you do not feel it.