Weird Transmission Issue

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Neveragain55
Posts: 165
Joined: Wed Mar 13, 2013 12:58 am
Location: Connecticut

Weird Transmission Issue

Post by Neveragain55 »

Hi Gang,

I have a really weird one here and I’m hoping one of you experts have either come across this before, or are familiar with this particular issue.

My car (like most of your cars) is not a daily driver and hasn’t been one for a long time; she’s a garage queen that only see’s sunny Sundays here & there.

The car has sat for long periods of time throughout the 18 years I’ve owned her and whenever I’ve gone to take her for a drive (regardless of how long she's sat) the transmission engaged right away and off we went.

I did go into the servo pack about 6 years ago and I took all of them out, flushed & cleaned all the grit & debris off & out of them, put everything back together, and put in new transmission fluid.

She shifted a lot smoother after that and she’s never slipped……….until yesterday.

I went to take her out for an errand to stretch her legs. Reverse was fine as she engaged right away with no slippage, but when I put her in drive she slipped fiercely and the car was barely moving.

I checked the transmission fluid level and it looked a bit low (but there are no puddles underneath the car).

I put enough transmission fluid in to see it register on the dipstick as full and she got a little bit better but not 100%.

I’ve read a lot about how when cars sit for a long time, the clutches in automatic transmissions can seize or stick together and cause these types of symptoms. But as I've stated this car has sat for extremely long periods in the past and never gave me these types of problems.

The transmission in this car has never given me any problems previously, and I’m hoping one of you can give me some insight here.

As usual, thanks in advance…….
1964 Ford Thunderbird
1970 Lincoln Mark III
1977 Datsun 280Z
1979 Suzuki GS750E
1989 BMW 635 CSI L6
1997 Mercedes SL500
2009 Volvo S60
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Neveragain55
Posts: 165
Joined: Wed Mar 13, 2013 12:58 am
Location: Connecticut

Re: Weird Transmission Issue

Post by Neveragain55 »

Ok, so nobody ever responded and I'm guessing it's because folks were tired of seeing the same question and figured I should have found a thread with the answer if I looked (which I did and found nothing) or were truly stumped. Either way its fine, it sort of resolved itself.

I have an update just in case somebody else ever runs across the same weird issue.

I started her up the other day when we had a 50 degree day here in Connecticut and I let her warm up for about 10 to 15 minutes.

Each time I engaged reverse the transmission responded well, and each time I put the shift into drive the transmission responded better than the day it was slipping.

I kept going from reverse to drive allowing the car to roll 10 to 20 feet backwards & forwards and each time I did that - drive seemed to get better & better.

Eventually, I pulled her all the way out of the garage, and drove her a little bit and drive seemed to be much better with no hesitations and no slipping.

I'm slowly coming to the conclusion that the car was just really cold the day the major slipping occurred and the fluid must have been like molasses. Also, the clutch plates may have been bound-up, stuck, frozen, or whatever, but she seems to be ok now.

I guess the lesson is to try to get to her much more frequently without letting long expanses of time to pass between driving intervals, and to let her warm up a lot more on frigid days.
1964 Ford Thunderbird
1970 Lincoln Mark III
1977 Datsun 280Z
1979 Suzuki GS750E
1989 BMW 635 CSI L6
1997 Mercedes SL500
2009 Volvo S60
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Sbeaud
Posts: 279
Joined: Fri Jan 04, 2019 9:38 pm
Location: Okahumpka, Florida USA

Re: Weird Transmission Issue

Post by Sbeaud »

I can't offer much more than speculation since I'm not at all familiar with BMW/ZF automatic transmissions. But back when I did mess with domestic automatics the seals were also quite critical. Old seals would not hold pressure in various circuits of the transmission. O rings, square cut rings, lip seals were throughout a domestic transmission and if they were hardened due to age (35 years worth!) then it was possible to poorly engage a clutch.

I think the initial lack of response may be due to most of the posters having manual transmissions?

Good luck!

Scott
1988 M6
plip1953
Posts: 400
Joined: Mon Aug 13, 2018 4:15 pm
Location: Leeds

Re: Weird Transmission Issue

Post by plip1953 »

Glad it's looking like it's sorted itself.

The idea that old seals not performing as well a they once did sounds plausible, although I have no real insight into whether this might have been the case in this instance.

During the 31 years of ownership my car has been known to sit for several years at a time and I purposely don't start it on a regular basis ever since I found that my exhaust system really didn't appreciate it (rapid corrosion of the back box from the inside out), even if I let the engine warm up pretty well. Fortunately, thus far (famous last words perhaps!), it has then always fired up without a problem.

But what I did start noticing, but only very gradually, and over quite a number of years, was a slight laziness in the way forward and reverse would engage. I didn't really think this was unusual given that the fluid had never previously been changed so I set out doing just that, and replacing the filter while I was at it. The results turned out well, but what I did struggle with for a bit was getting the fluid level just right. I don't know about others, but I'd previously thought that the gearbox gearbox dipstick worked just that that for the engine, but of course that isn't the case, but I got there in the end.

I'm not sure any of the above will be of any help to you, but are you sure your oil level is correct and maybe there would be merit in doing a complete oil and filter change?
Phil
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1988 Highline 635 CSi
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