2000 S70 Doesn't Coast

deardeergod · Post by **deardeergod** » 05 Apr 2017, 13:52

I've had this issue for the four years I've owned this car, nothing major, but it just doesn't coast right. Well it hardly coasts at all.

It's most noticeable when I'm going down a hill and off the gas. It feels like something is holding my car back and it doesn't speed up as it goes down the hill. The "holding back" sensation is accompanied with the tachometer steadily rising and can get up to 2000 rpm or more. Then, all of a sudden, the force that was holding the car back is gone and the tachometer is down to 1000 rpm and I'm steadily coasting. The car can also "jerk" where it goes from holding back, to coasting normally, and then back to the holding back sensation with the tach rpms following in suit.

I've learned that when I feel this response when going down a hill, I can blip the gas and the tach will settle down to the 1000 range and I'm free rolling.

Is this just some weirdness with the transmission or the TCM control? Or is there some other component at fault here?

Post by **scot850** » 05 Apr 2017, 13:57

When was the transmission fluid last changed? Do you have any warning lights on on the dashboard?

Do your parking brakes work at all? Have you checked them out and serviced them recently? Could be they are dragging and blipping the throttle is releasing a dragging brake cable or delaminated parking brake shoe.

I made the assumption you are driving an auto, not a standard shift?

Neil.

deardeergod · Post by **deardeergod** » 05 Apr 2017, 14:16

I don't remember an exact date for the last transmission fluid change, but the fluids are all maintained and accounted for. No warning lights and yes it's an automatic.

The parking brake does not work, it hasn't since I got it... that could very well be the issue. I've been wanting to get it fixed but it was always a low priority and often forgotten.

Post by **abscate** » 05 Apr 2017, 14:29

It sounds like the torque converter is locking/unlocking unreliably. When it is locked, the car will engine brake (rpms hold steady when you lift) - when unlocked they drop when you lift.

Does that fit your symptoms?

deardeergod · Post by **deardeergod** » 05 Apr 2017, 15:48

That does seem to fit the issue. I'll fix the parking brake first before going after the torque converter. The issue hasn't gotten any worse since I got the car, but is there a chance the torque converter could fail completely?

Post by **wizechatmgr** » 05 Apr 2017, 17:30

It's possible but I'd bet it is a lock-up solenoid getting stuck. I'd replace the fluid now - if only to be able to say you know the date it was last changed.

Don't feel bad, it's on my to-do list too...