View Full Version : SYMPTOM: Feels like Tranny Slipping when
Ferret
04-29-2008, 06:56 PM
Not the clutch... The clutch was replaced just about 40K miles ago AND i have been careful to watch the tach when this phenomenon occurs and it does not rev as it would and did when the clutch begins to fail.... next?
A manual transmission cannot slip - unless you have massive failure internally and your gearbox teeth have been all stripped off... the only place slippage can occur in the drivetrain of a manual is the clutch or guibo.
It's perfectly possible to burn out a 540 clutch in 40k miles with a bit of spirited driving... ask me how I know.
If your revs are not rising disproportionately to your road speed - I'd say you've got something wrong with your engine.
Most likely a massive vaccum leak or the like - when in top gear and accellerating the engine's running at the most stress - any ****up in the mixture and you're gonna feel it.
accelerating in a higher gear SOMETIMES. Mostly when going up hill and i fail to downshift,have slowed then try to accelerate.Independent of ASC.. Is this the beginning of the end for this Tranny or is it just low fluid? I have seen Tranny fluid on that rear seal as far back as just after I bought it when up on a lift. Never filled it .. Can I get some fluid added and expect this occasional slipping to recede or will it just get rapidly worse till it just blows up on me going up a hill at 2AM in the middle of nowhere?
Sixdown
04-29-2008, 10:51 PM
I have this issue in my '85 525e. Its the tranny slipping in my case, and the fluid didn't solve it, although it did minimize its obviousness. Your car's wear is in the right range at 220k.
I have this issue in my '85 525e. Its the tranny slipping in my case, and the fluid didn't solve it, although it did minimize its obviousness. Your car's wear is in the right range at 220k.
So I should start shopping for a new tranny huh? Any idea if the failure point is sudden and total or can i expect several tens of thousands of miles ?
Sixdown
04-30-2008, 12:09 AM
ive gone around 2k miles without it crapping out...so its hard to tell. change your fluid first and see what happens.
Sounds like its a good thing I've been seeing bigger paychecks recently... I was getting ready to drop around $2,600.00usd on the Timing chain cover gasket and power steering leaks... glad this showed up before i did that or i'd have a nice Oxfordgruen ornament for my parking space..ugh.
bubba966
04-30-2008, 01:04 AM
You do have a manual, right? If so your clutch is on it's way out. A friends '93 M5 was doing that and it was because the clutch needing replacing, the tranny was fine.
Not the clutch... The clutch was replaced just about 40K miles ago AND i have been careful to watch the tach when this phenomenon occurs and it does not rev as it would and did when the clutch begins to fail.... next?
A manual transmission cannot slip - unless you have massive failure internally and your gearbox teeth have been all stripped off... the only place slippage can occur in the drivetrain of a manual is the clutch or guibo.
It's perfectly possible to burn out a 540 clutch in 40k miles with a bit of spirited driving... ask me how I know.
If your revs are not rising disproportionately to your road speed - I'd say you've got something wrong with your engine.
Most likely a massive vaccum leak or the like - when in top gear and accellerating the engine's running at the most stress - any ****up in the mixture and you're gonna feel it.
Hmmmmmmm.... veeeeery interesting..... lets say I'm sure the feel of this condition is nothing like the feel of my clutch going . This is like a series of "bangs" ,not backfires ,like when an Automatic Transmission slips, " like it lets go a bit then hits ,let's go, hits, etc.. The way i remember the clutch failing did not cause any hard banging it was just smooth failure to engage, I press the gas pedal, the revs climb but the speed didn't increase ..never having owned a manual before i assumed from past experience it was the tranny slipping. OK. well I'll watch the car for a while and see if i can pin it down any better. Thanks for the helpful info.
I think your problem isn't in the driveline. If the revs don't climb the clutch isn't slipping.
You could be feeling the fuel or ignition dropping out. This will cause it to "buck" which I think you are describing.
whiskychaser
04-30-2008, 12:47 PM
Apply handbrake. Put it in 3rd. Let clutch out. If it stalls clutch is good enough - for now.
I think your problem isn't in the driveline. If the revs don't climb the clutch isn't slipping.
You could be feeling the fuel or ignition dropping out. This will cause it to "buck" which I think you are describing.
Bucking is closer to the feeling.. I thought it was coming from the back end so with my past experience owning auto trannys and feeling them "slipping" i made the assumtpion. So what comes to mind there is that i discovered Oil in the Ignition Coil Boots last time I replaced plugs. The seller just a few months prior had said he replaced the VC Gaskets and I didn't have the time when i began the plug swap to do it again then so I just cleaned the boots and closed up. If the oil leaking was Post VC change back when I bought the car then the leaking would continue , perhaps this is the culprit? I guess i assumed any misfiring would sound more like backfire whereas this feels and sounds like a mechanical event but I am of course not a trained BMW tech so i speculate.. A friend suggested the ASC system was malfunctioning any ideas about that?
ASC's intervention is smoother. Weak ignition will really show under load, which are the conditions you describe.
ASC's intervention is smoother. Weak ignition will really show under load, which are the conditions you describe.
I did the hand brake deal and the car immediately began to stall so Clutch=Good. I mentioned the Oil in the Coil Boots i found last plug swap to my Indy Shop and he said what I described is EXACTLY what I'd feel if "Under Load.." there was oil getting in to the boots.. I'll check them. Drove it good and hard today and it only happened once accelerating in third from a near stop on level road so I'm encouraged. thanks to everyone who helped.
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