GIGM08GT

Just what it says, I have a knock towards the rear of the car anytime I change direction (forward reverse). I'm thinking U joints but could it be something else?

College Student during finals = no time to crawl under car for about a week

TrailReadyXJ

Sounds like a U-joint to me, I have had MANY go bad in my Jeep (andother cars)in the way your describing. If it's to the point of clunking, you really need to replace it ASAP or it cando more damage.Aside from the possibility of the drive shaft falling out, abad joint can cause an unbalanced drive line, eventually leading to worse things like transmission or rear end bearing damage.

To make sure thatis yourproblem.. On level ground,set the parking brake and press the clutch in to relieve the stress off the drive shaft (on N if auto). You can leave it in gear (or P) to help take out some additional playin the shaft, just make sure the brake is holding it.Some rotational play in the drive shaft is normal, andcaused by the backlashof thegears in the diff. Just reach under there,grab the shaft, and give it a couple yanks and twists(that just sounds wrong out of context!).If you detect unwanted movement, try to narrow it down, as there is a slight chance it could be something else, but you'll probably find the bad joint easily. I'd suggest replacing both joints since the other can't be far behind.

The joints are cheap ($15-20) are easy to change as long as you have the right tools. You can rent/borrow a press from Advance, Autozone, etc... If you don't want to tackleit yourself, don't let a mechanic overcharge you, this can be fixed in under an hour. I can change them in my Jeep in about 15min, but it's a whole lot easier to get under to work on!

Burtonsnow157

every once in a while when i start from a light i hear this also, its very intermittent, could it be the same thing?

GIGM08GT

Thanks for the info! If the weather is good I may be able to do it Wednesday. Hopefully thats the only problem.

1999 GT

my buddy was havin a similar problem with his 03 gt, there was a knocking sound coming from the rear end...he brought it to 2 mechanics, and both said his u joints were goin....it turned out that the lug nuts were loose and the wheels were wobblin around causing a knocking sound lol...so you never know

GIGM08GT

Dang, I'll check that too. The last person to tighten the lugs down was my friends little bro. He know his way around the garage but **** happens sometimes.

Snowman117

Actually I have been having a similar problem. I haven't checked the lug nuts, but I did change the u-joints and they wern't bad. I also am in the process of changing the motor mounts because it only happens when I go from a dead stop or disengage the clutch from a high rpm. Its really weird. I have a 98 gt. I'll have to check the wheels. I'll let you know how it all goes. Plus I hear the college finals situation, I have been so busy between changing the u-joints and motor mounts, I haven't gotten to drive my car once this season yet.

rossn

my knock was the rear transmission bolts were loose.

Snowman117

Yea I, checked my lugs, and changed the motor mounts and it still makes the knocking noise from dead stop.I'll see if its the rear trans bolts. Has anyone else had this problembecause its really bugging me?

rossn

For me it was most noticeable from a dead stop putting it in drive or reverse. I also heard the rear of the transmoving aroundat low speeds.