Volvo newb freeway speed thump/jerk issue question

**fouronefive** · 05-29-2010, 10:15 PM

I have a 1998 V70 XC AWD with 118,400 miles on it. I'm having a weird jerking/hesitation/thump issue when driving at freeway speeds. It sort of feels like I've just run over a bump really quickly. Sometimes it happens when I'm accelerating quickly to pass, other times when I'm cresting a steep hill. I've searched the forums and tried to pinpoint an answer and I apologize if I'm reposting here. I just don't know what to do.

I just changed oil, flushed and replaced trans fluid, replaced spark plugs, air filter, replaced coolant and installed a new temperature gauge. One of my engine mounts is broken and a cv boot and axle will need to be replaced on the right-side, which I will be fixing in the coming days.

It felt as if the maintenance I did made the jerk/thump a bitter quieter, but that could just be my brain being overly positive.

Could it be:
1. Trans?
2. Engine mount/CV boot?
3. AWD issue?

All insights and suggestions would be greatly appreciated.

Thanks.

**knucklebuster** · 05-30-2010, 06:23 AM

I would have said plugs as a start, but maybe a coil. Have you used any injector cleaner lately?

**Hankeester** · 06-02-2010, 04:37 PM

I've got that same jerk while driving at high speeds almost like it's kicking the rear end of the car to the side. I just had a valve job and new plugs done. It seems like it's a tran/suspension thing.

**JRL** · 06-03-2010, 04:31 AM

Sounds like the tranny... torque converter failing.
If it's going in and out of lockup that's probably what it is

**Hankeester** · 06-03-2010, 04:34 AM

excellent...

**tunger2000xc** · 06-03-2010, 11:17 AM

Just a thought, but I'd look at the Viscous Coupler. As these start to fail, many of the symptoms you describe, have been reported.

**Hankeester** · 06-03-2010, 11:26 AM

I don't suppose the bad u-joint in the drive shaft would be causing this hiccup at high speeds? I'm taking it in Tuesday to have an authorized V dealer diagnose the problem. I'm also gonna have them yank the driveshaft and do the FWD thing until winter hits then get a new one from Colorade Driveshaft.

**srs** · 06-21-2010, 08:18 PM

Try the trans flush again but with different fluid as described below. Although not required for your model year JWS 3309 fluid fixed the same problem with my 1998 V70XC.

http://www.volvoxc.com/resources/how...e-bulletin.pdf