mls@harpo.UUCP (08/02/85)
Does anybody had any experience with the 4 speed automatic transmission used in Buick Park Avenue or Oldsmobile 85 cars. I now have a second transmission in the car and at 8000 miles on it, there are problems in downshifting rom the overdrive to drive speed. It does not happen all the time but it can be a very rough shift. I believe it is down shifting from 4 to 3 without removing the lockup on the torque converter. The service manager claims that is the way it is supposed to happen but the 800 number for Buick claims the torque converter lockup is supposed to come off before the downshift. I have the service manual at home, but it is a package a foot thick. I guess I will finally have to break down and fine the right section. Any comments will be appreciated. Irv McNair ATT Bell Labs, Whippany 8-232-4162 9-386-4162 .
bccarty@whuts.UUCP (Brian C. Carty) (08/06/85)
> Does anybody had any experience with the 4 speed automatic transmission > used in Buick Park Avenue or Oldsmobile 85 cars. I now have a second > transmission in the car and at 8000 miles on it, there are problems > in downshifting rom the overdrive to drive speed. It does not happen > all the time but it can be a very rough shift. I believe it is down > shifting from 4 to 3 without removing the lockup on the torque converter. > The service manager claims that is the way it is supposed to happen > but the 800 number for Buick claims the torque converter lockup > is supposed to come off before the downshift. > I think the service manager is correct. The transmission is supposed to be a regular 3 speed with torque converter plus an overdrive gear. I've only had experience with this trans on one car (a rented Caprice) and the shifting behavior confused me too at first, because I felt two pulses when I shifted from 2 to D manually. Either way, you would get similar shifting behavior if the car was trying to downshift from 4th to an unclutched 3rd gear. I found it rather fun myself, but then I never liked automatics that shifted meekly anyway. -- Brian C. Carty AT&T Bell Laboratories - Piscataway, NJ ..!{ihnp4|allegra}!whuts!bccarty