Auto bucking sensation when torque converter is engaged

[Inday]

I got a nasty bucking sensation when the torque converter is locked and then I slow down close to the speed limit where the torque converter will soon unengage (around 60 km/h what is about 35 mph). When I go off the gas and try to accellerate slightly again, there is that nasty bucking sensation. It does neither do it when torque converter is not engaged nor when driving faster speed, it is just doing it between 35-40 mph. Is there something to be worried about? It is very nasty because it is the speed driving very often in heavy traffic. I like to mention also, that it happens just the first time I try to accellerate again, if I reproduce it the second time the bucking sensation has gone. So when accelerate again to faster speed, let it drop down again to the critical speed and then there it is reproducable.

 

The Subaru dealer told me that some cars of that model have that "problem" but he did not consider it as a problem.

 

Another problem is that when I manually switch gear from 4. to 3. then it is jerky, but very smooth from manually switching gear 3. to 2. Upswitching all gears is smooth and no problem.

 

Thanks for your advices.

 

I have got a Legacy 2. Gen. Auto 2.2 make '95.

[Legacy777]

Mine used to do that. Have you changed the fluid recently? I'd suggest that as a first step to try and help. Maybe put some synthetic fluid in.

[Inday]

Thanks Josh, the fluid was changed but it was not better afterwards. Perhaps I should use a different fluid? It's the ATF Subraru advices to use. I cannot tell you the specification for the Subaru dealer did the change.

 

 

Any other ideas?

[Legacy777]

I don't really think a different fluid will do much else, synthetic might be better since it'll probably clean the insides a little more. Unfortunately, I don't know of anything else you can do.

 

Seafoam makes stuff called transtune. I haven't used it, but have used their engine product. If you can find the transtune stuff, it might help www.seafoamsales.com

[JOEK39]

2001 Forester w/ AT - 60K miles

 

Got a bad tank of gas and the car drove like crap (surging, stalling, backfiring, missing, pinging) until i could run the gas through - much better, but not great like it was before the bad gas so i changed the fuel filter AND reset the ECU.

 

All bad gas symptoms gone, except now I have this slight but annoying "bucking" problem that occurs just as described in this thread - reproducible if going downhill at 35 mph coasting.

 

I am convinced it was the ECU reset that caused this. I could do another reset, except I am now getting the best mileage EVER since I purchased this car new 6 years ago. Getting 24-26 mpg every tankful, versus 20-23 previously.

 

I think I'll live with the bucking for a awhile - the 3-4 mpg increase is worth over $200 per year!

 

 

 

I got a nasty bucking sensation when the torque converter is locked and then I slow down close to the speed limit where the torque converter will soon unengage (around 60 km/h what is about 35 mph). When I go off the gas and try to accellerate slightly again, there is that nasty bucking sensation. It does neither do it when torque converter is not engaged nor when driving faster speed, it is just doing it between 35-40 mph. Is there something to be worried about? It is very nasty because it is the speed driving very often in heavy traffic. I like to mention also, that it happens just the first time I try to accellerate again, if I reproduce it the second time the bucking sensation has gone. So when accelerate again to faster speed, let it drop down again to the critical speed and then there it is reproducable.

 

The Subaru dealer told me that some cars of that model have that "problem" but he did not consider it as a problem.

 

Another problem is that when I manually switch gear from 4. to 3. then it is jerky, but very smooth from manually switching gear 3. to 2. Upswitching all gears is smooth and no problem.

 

Thanks for your advices.

 

I have got a Legacy 2. Gen. Auto 2.2 make '95.