View Full Version : Tranny windup then loud thunk!
jmdgolfman
06-16-2008, 10:33 AM
We just purchased a used 2006 XC70 with 29K miles. We bought it from a Hyundai dealer who had the car as a trade in. During the test drive everything seemed fine (of course).
After we took ownership of the car (only 1 week now) we immediately started noticing a loud thunk sound at freeway speed. Since we first started noticing it, we've determined exactly when it happens. Here are the details:
1) Car has been parked, engine off.
2) Start up car, drive on city streets, parking lot etc, get on freeway.
3) Upon accelleration the transmission doesn't seem smooth. It sorta vibrates through the gas pedal and as a passenger you can feel it as well.
4) You can feel it on the city streets, but after a while on the freeway the car just seems like it's not running smooth, then all of a sudden you will feel a large clunk sound. To me it feels like it's right in the middle to rear of the car and it transferred through the rear wheels. My wife thought she hit something in the road.
5) After the loud thunk/clunk sound the car runs smooth as glass. It feels as though some tension has built up in the transfer case or transmission, then after it pops, it runs smooth until the next time you turn the car off.
6) We tested and repeated this yesterday to confirm exactly how/when it happens.
We're new to owning a Volvo, and have scoured the forums this morning looking for a similar post. I've seen a few posts regarding tranny replacement, transfer case etc. But nothing exactly like this
Anyone have any ideas? Could it be a computer problem, sign of transmission going out, bad transfer case, etc?
At this point, I've extremely happy to have purchased the extended warranty, and also that the car still has a bit left on the original 36K factory warranty.
Thanks in advance for any advice, or pointing me to an existing post etc.
-J
wgriswold
06-16-2008, 11:00 AM
I am not enough of a mechanic to have any advice regarding your problem, but I have had good luck with Turner Volvo if it comes down to going to a dealer. They are not cheap but are friendly, helpful and seem to know what they are doing.
Good luck. More knowledgeable people will probably reply with more specific suggestions.
Well, if you're in the US it's 4 yr, 50,000 mile warranty.
Regardless, get it to the dealer NOW, this is not even close to normal, you have a (big) problem!
jmdgolfman
06-16-2008, 12:17 PM
JRL, thanks for pointing the warrany out to me! For some reason I thought it was only a 3 year / 36,000 mile warrantly (probably what the used car salesman told me). I just looked it up on Edmunds and it is indeed 4 year / 50,000 miles.
http://www.edmunds.com/used/2006/volvo/xc70/100553034/standardwarranties.html
We'll take it in to Turner Volvo ASAP!
volviste
06-17-2008, 02:44 AM
Hi, change the tyres quickly.
Sorry for my English. If you don't change the tyres, you are
going to have a bevel gear or AWD mechanism issue.:o
What does that have to do with anything? :confused:
He has an HALDEX, 2006 XC, not really affected by tires
psaboic
06-17-2008, 06:48 AM
Could it possibly be a rear brake sticking, and then the loud clunk is it finally letting go
mbsl98
06-17-2008, 08:44 AM
As a refinement to the rear brake point, I would look more specifically at the parking brake sticking and releasing. The p-brake works brake shoes inside the rear wheel rotors, and would sound just like that if it was sticking and then released while you were moving. One check is to pull up some on the parking brake while moving (not too fast) and see if it takes up smoothly and releases smoothly. Remember this is not designed to stop teh car, sodon't really yank onit, just check that it is engagning and releasing smoothly - do this just at the beginning of one of these trips when you think things are not running well, and then later, when everything has settled down, and see if there are any differences in the brake action.
Could it possibly be a rear brake sticking, and then the loud clunk is it finally letting go
Nope. IF that happens, it happens ONCE on start up
psaboic
06-18-2008, 06:37 AM
We just purchased a used 2006 XC70 with 29K miles. We bought it from a Hyundai dealer who had the car as a trade in. During the test drive everything seemed fine (of course).
After we took ownership of the car (only 1 week now) we immediately started noticing a loud thunk sound at freeway speed. Since we first started noticing it, we've determined exactly when it happens. Here are the details:
1) Car has been parked, engine off.
2) Start up car, drive on city streets, parking lot etc, get on freeway.
3) Upon accelleration the transmission doesn't seem smooth. It sorta vibrates through the gas pedal and as a passenger you can feel it as well.
4) You can feel it on the city streets, but after a while on the freeway the car just seems like it's not running smooth, then all of a sudden you will feel a large clunk sound. To me it feels like it's right in the middle to rear of the car and it transferred through the rear wheels. My wife thought she hit something in the road.
5) After the loud thunk/clunk sound the car runs smooth as glass. It feels as though some tension has built up in the transfer case or transmission, then after it pops, it runs smooth until the next time you turn the car off.
6) We tested and repeated this yesterday to confirm exactly how/when it happens.
We're new to owning a Volvo, and have scoured the forums this morning looking for a similar post. I've seen a few posts regarding tranny replacement, transfer case etc. But nothing exactly like this
Anyone have any ideas? Could it be a computer problem, sign of transmission going out, bad transfer case, etc?
At this point, I've extremely happy to have purchased the extended warranty, and also that the car still has a bit left on the original 36K factory warranty.
Thanks in advance for any advice, or pointing me to an existing post etc.
-J
Reading line 5 of the original post, I get it as the problem only does happen once....each time the car is started after being shut off/parked. IF they use the parking brake each time they park, then it still might be the brake.
I'm not saying the brakes are the issue, just something I would check.
Glenn
Reading line 5 of the original post, I get it as the problem only does happen once....each time the car is started after being shut off/parked. IF they use the parking brake each time they park, then it still might be the brake.
I'm not saying the brakes are the issue, just something I would check.
Glenn
Tranny does not "wind up and thunk" if this is the issue
it happens right when you first try to move it (stuck brake)
jmdgolfman
06-18-2008, 08:16 AM
Actually, the tires may turn out to be the problem after all. I just took the car in to Turner Volvo in Sacramento this morning. The first thing they noticed, and I feel stupid for not noticing it sooner, was that there are two different sized tires on the car. The front ones are 215/55/16 and the rear (OEM Pirelli Scorpions) are 215/65/16. Turner wouldn't even submit a work order until all 4 tires are the same. The service advisor was very helpful. Basically since the front tires are a smaller diameter they are spinning faster than the rear tires. The AWD computer tries to compensate for this for a while, then finally "thunk" it gives up an disengages. The bad news is that damage may have already been done. So it's back to the Hyundai dealer where we bought the used car, and request that they give me 4 brand new tires of the correct size.
Thanks for everyone's help and suggestions. I'm really glad I found this forum. I'll post back the outcome of the problems later.
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