interesting transmission failure

[dougn]

my 92 535 automatic was accelerating onto the freeway when i heard a metallic bang...not too loud... and then the engine revs up freely. there was a complete disconnect from the drive train...like a shaft broke. there was no grinding or any noise at all like the crunching of metalic parts. it's not the drive shaft or the rear end...

what could behave this way in an automatic transmission? i was thinking it may be the torque converter. the transmission was operating ok up untill that point, but the car had a lot of drag in gear at idle.... like the torque converter wasn't slipping freely as is should be.

any ideas?

[Kalevera]

What does "drag[ging] in gear at idle" mean?

It might have just blown out the forward a clutchpack and maybe cracked the basket (hence the bang). The former is common, the latter is an expensive part to replace (and may merit replacing the trans with a reman, or depending on how you feel about it, the car). This problem would "disconnect" the drivetrain and would keep it from going forwards and, perhaps, backwards as well. How many miles on it/how often do you change the filter and fluid? It's funny that the engine now revs a lot easier, though.

best, whit

[dougn]

draging means it wants to move forward like a normal automatic except excessive

[pundit]

draging means it wants to move forward like a normal automatic except excessive

Did it ever creep very slightly (drag) whilst in neutral after you had been driving for a while? Kind of sounds like it maybe the dreaded 'A' clutch syndrome... fluid leaking past the front seal a pressurising the clutch and causing partial engagement (slippage) which can burn it out. The metallic bang maybe as Whit suggested. I think a visit to the trans doctor for a quote maybe in order. If you were ever comtemplating a five speed manual conversion, now is the time to seriously consider it!

[winfred]

http://www.bimmer.info/forum/showthread.php?t=780

[Kalevera]

oh yeah...then def. that's your problem. Read Winfred's stuff

[dougn]

no it never creeped while in neutral. however a 5 speed swap sounds very interesting. i wonder what it would cost and what are the details.

does the clutch/flywheel set-up bolt right up? is there a chip change needed? does the 5 speed use a different drive shaft?