Jerking auto transmission

[Podmore]

Just when i thought I'd get a few weeks pleasurable driving, having fixed the latest gremlin, I start to get a sort of jerking that seems to originate in the trans. That is, it's not a misfire, it's like someone slammed the brakes on momentarily bam-bam-bambam. Occasionally happens on high speed coast (ie. going downhill on a trailing throttle) and sometimes on a cruising throttle. Take-off seems to be a little jerky and hesitant too like it's trying to shift up too soon then drops back into the lower gear. I tried flicking into neutral and coasting to see if the problem recurred under no load, and noticed a bit of a thump as it went into neutral, but going back into drive no noise and trans seemed to pick up smoothly. Trans fluid level is OK but I have no idea when it was last serviced. Anybody have a test regime that I could employ to pinpoint the problem?

[bmwrp8]

Just when i thought I'd get a few weeks pleasurable driving, having fixed the latest gremlin, I start to get a sort of jerking that seems to originate in the trans. That is, it's not a misfire, it's like someone slammed the brakes on momentarily bam-bam-bambam. Occasionally happens on high speed coast (ie. going downhill on a trailing throttle) and sometimes on a cruising throttle. Take-off seems to be a little jerky and hesitant too like it's trying to shift up too soon then drops back into the lower gear. I tried flicking into neutral and coasting to see if the problem recurred under no load, and noticed a bit of a thump as it went into neutral, but going back into drive no noise and trans seemed to pick up smoothly. Trans fluid level is OK but I have no idea when it was last serviced. Anybody have a test regime that I could employ to pinpoint the problem?

hhmmm... are you sure its not the engine that is having a misfire? like injectors clogged misfire? if not check your prop.shaft , center bearing , and guibo. Are you having that dreaded "trans progarm" message in the check control display?

[Podmore]

Pretty sure it's not a misfire, it's not at all like a power loss - more like either a cylinder firing out of synch or the ABS grabbing for a split second (although it's not felt through the steering wheel, more like seat of the pants). New injectors about 1500 km ago, new plugs, leads, distributor cap, CPS in the last 6 months. Tailshaft centre bearing replaced within the last 4 months, and there is no guibo on my 88 auto. No trans check message. Dammit. Couldn't I just have a full week with no new problems?

[Randell]

does it feel like a rapid jolt that pretty much travels down the whole car, with a 'clank-clank-clank' noise?

i had my auto rebuilt a couple of years ago, it failed again after 4000km with these symptoms... just driving along coasting and suddenly the car would jolt and buck repeatedly, then stop after a while, or when i stabbed the throttle... turned out the torque converter had fused shut, needed another rebuild

according to the transmission guy, who i reckon was full of **** cause he rebuilt it the first time without touching the TC, it was a loose solenoid that caused the TC to remain locked all the time... in the process of driving it though i toasted the tranny again, stuffed a prop shaft u joint (i ended up replacing the whole thing) and i reckon my diff is a bit rattly now too.. tsk!

i'd take it to a transmission shop and get it checked out, they'll only charge you $20 or so if you don't get any more work done to it

[Ferret]

Mine does this - about once every 50 high power kickdowns.

It's quite alarming when it does it because it's like it's dropped/snatched a clutchpack :/

[bmwrp8]

Pretty sure it's not a misfire, it's not at all like a power loss - more like either a cylinder firing out of synch or the ABS grabbing for a split second (although it's not felt through the steering wheel, more like seat of the pants). New injectors about 1500 km ago, new plugs, leads, distributor cap, CPS in the last 6 months. Tailshaft centre bearing replaced within the last 4 months, and there is no guibo on my 88 auto. No trans check message. Dammit. Couldn't I just have a full week with no new problems?

do you have ASC?

[Podmore]

do you have ASC?
Nope. nor STD or PMS.

[[1990]525]

does it feel like a rapid jolt that pretty much travels down the whole car, with a 'clank-clank-clank' noise?

i had my auto rebuilt a couple of years ago, it failed again after 4000km with these symptoms... just driving along coasting and suddenly the car would jolt and buck repeatedly, then stop after a while, or when i stabbed the throttle... turned out the torque converter had fused shut, needed another rebuild

according to the transmission guy, who i reckon was full of **** cause he rebuilt it the first time without touching the TC, it was a loose solenoid that caused the TC to remain locked all the time... in the process of driving it though i toasted the tranny again, stuffed a prop shaft u joint (i ended up replacing the whole thing) and i reckon my diff is a bit rattly now too.. tsk!

i'd take it to a transmission shop and get it checked out, they'll only charge you $20 or so if you don't get any more work done to it
I had the same frightening jolt that would consistently appear above 40mph. It was very scary on a highway because it shook the car so much that you felt you couldn't keep control of the car. Turned out it was loose control arms <cheap yes!>