Weird auto transmission problem
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- Posts: 20
- Joined: Fri Sep 04, 2015 8:45 pm
- Location: NYC
Weird auto transmission problem
Hello all!
I'm new to the forum and what a sucky post to say hello with but I just bought an 88 635csi and the auto transmission started acting up The previous owner said they had rebuilt the tranny a few years ago.
The car shifts into gear and drives but then it will just stop shifting as if it's in neutral. It will be in "D" but the engine will just rev and the car won't move. The only way for the car to move is to shut it off and restart it. Took it to my local mechanic but he couldn't find any leaks or anything out of the ordinary.
What do you guys think it could be? Thanks
I'm new to the forum and what a sucky post to say hello with but I just bought an 88 635csi and the auto transmission started acting up The previous owner said they had rebuilt the tranny a few years ago.
The car shifts into gear and drives but then it will just stop shifting as if it's in neutral. It will be in "D" but the engine will just rev and the car won't move. The only way for the car to move is to shut it off and restart it. Took it to my local mechanic but he couldn't find any leaks or anything out of the ordinary.
What do you guys think it could be? Thanks
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- Posts: 20
- Joined: Fri Sep 04, 2015 8:45 pm
- Location: NYC
I would inspect the flex plate and the propshaft etc to see that it is still in one piece; something might be broken.
I would also check to see that the gear lever is correctly adjusted where it goes into the gearbox.
Losing all drive is a bit unusual to say the least. Can you still select 'P'?
Is the oil level OK?
cheers
I would also check to see that the gear lever is correctly adjusted where it goes into the gearbox.
Losing all drive is a bit unusual to say the least. Can you still select 'P'?
Is the oil level OK?
cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Hey Brucey! Thanks for responding.Brucey wrote:I would inspect the flex plate and the propshaft etc to see that it is still in one piece; something might be broken.
I would also check to see that the gear lever is correctly adjusted where it goes into the gearbox.
Losing all drive is a bit unusual to say the least. Can you still select 'P'?
Is the oil level OK?
cheers
Park is still selectable and the transmission will lock when selected. My indy mechanic put it on a lift and everything looked fine from under the car. He also checked the oil level and it was fine. I'm just really hoping I don't have to drop the transmission.
The issue that has me stumped is that when the engine is shut off and then started again, it will drive but then stop after a few minutes. Before it happens, I can hear a hissing sound as if pressure is being lost somewhere and the car becomes sluggish.
It has been extremely hot and humid here in New York the past few days, so I'm wondering if the hot weather has something to do with it. Could it just be the transmission and oil overheating causing the clutch plates to lose friction? Would a transmission oil change hurt?
a hissing sound? That is odd.
Stupid question; you are dipping the oil level when the oil is fully hot, with the engine running, right? That is the way it should be done.
It just might be that the filter on the bottom of the tranny is
a) blocked and/or
b) loose or missing its seal.
This would (esp if the oil level is actually a bit low) result in the gearbox losing oil pressure once it has been running for a few minutes. The hissing sound might be the pump sucking on air?
I think that the gearbox can do all kinds of weird things if there is no oil pressure. Somewhere online there is a manual for these gearboxes which may help you to diagnose the fault better.
cheers
Stupid question; you are dipping the oil level when the oil is fully hot, with the engine running, right? That is the way it should be done.
It just might be that the filter on the bottom of the tranny is
a) blocked and/or
b) loose or missing its seal.
This would (esp if the oil level is actually a bit low) result in the gearbox losing oil pressure once it has been running for a few minutes. The hissing sound might be the pump sucking on air?
I think that the gearbox can do all kinds of weird things if there is no oil pressure. Somewhere online there is a manual for these gearboxes which may help you to diagnose the fault better.
cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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- Joined: Fri Sep 04, 2015 8:45 pm
- Location: NYC
Yes, oil level was checked with the engine hot. I'm going to try a full tranny oil and filter change and see if that solves the problem. More searching pulled up this thread:Brucey wrote:a hissing sound? That is odd.
Stupid question; you are dipping the oil level when the oil is fully hot, with the engine running, right? That is the way it should be done.
It just might be that the filter on the bottom of the tranny is
a) blocked and/or
b) loose or missing its seal.
This would (esp if the oil level is actually a bit low) result in the gearbox losing oil pressure once it has been running for a few minutes. The hissing sound might be the pump sucking on air?
I think that the gearbox can do all kinds of weird things if there is no oil pressure. Somewhere online there is a manual for these gearboxes which may help you to diagnose the fault better.
cheers
viewtopic.php?t=9817&highlight=automatic+transmission
Hopefully the oil and filter change solves it. I'll update this thread after. Thanks for all your help Brucey!
- Ralph in Socal
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Doesn't the 88/89 system utilize a trans control unit? I'm not that familiar with the later models.
Ralph
Ralph
There is a very fine line between "Hobby" and Mental Illness.
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Re: Weird auto transmission problem
I have a very similar problem. My 1989 635csi slips out of gear every now and then but only in 'E' if I put it in 'S' the problem never occurs. Only problem with that is that is of course I dont get top gear.crav4speed wrote:Hello all!
I'm new to the forum and what a sucky post to say hello with but I just bought an 88 635csi and the auto transmission started acting up The previous owner said they had rebuilt the tranny a few years ago.
The car shifts into gear and drives but then it will just stop shifting as if it's in neutral. It will be in "D" but the engine will just rev and the car won't move. The only way for the car to move is to shut it off and restart it. Took it to my local mechanic but he couldn't find any leaks or anything out of the ordinary.
What do you guys think it could be? Thanks
Greg
Re: Weird auto transmission problem
Sorry to resurrect a dead thread but did you ever figure out what was causing your problem? My car has the exact same symptoms you described and I haven’t had any luck finding a solution.