What could cause this problem?
What could cause this problem? Looks like my Formula is getting to a point where I'm going to have to be doing repairs on it for a while... I was noticing this yesterday when I was driving around in the Formula, and I'm trying to figure out what could cause this.
So anyway.. When I am driving the car slow, like just barely rolling to about 5 mph... I can feel this thump coming from the back of the car that seems to be perfectly timed with the rotation of the wheels.... one thump per rotation, it slows down and speeds up as the car does, and does not change under braking or cornering.. once I get up past 10mph I think it's happening so fast that it feels constant.
At first I thought it might be a flat spot in the tire or something, but it still did it after a 45 minute drive on the freeway @ 60+ mph the whole way.
It doesn't seem to make an audible sound, but it can definitely be felt and varies with the speed of the car..
Any idea what that might be?
So anyway.. When I am driving the car slow, like just barely rolling to about 5 mph... I can feel this thump coming from the back of the car that seems to be perfectly timed with the rotation of the wheels.... one thump per rotation, it slows down and speeds up as the car does, and does not change under braking or cornering.. once I get up past 10mph I think it's happening so fast that it feels constant.
At first I thought it might be a flat spot in the tire or something, but it still did it after a 45 minute drive on the freeway @ 60+ mph the whole way.
It doesn't seem to make an audible sound, but it can definitely be felt and varies with the speed of the car..
Any idea what that might be?
mud on the wheel or lose lug nuts... wild guesses both
look for worn spots or debris or something imebed in a tire.
Describe the thump better. Does the car shake move with it at all or is it strictly just an audible noise. You said you can feel a thump. Can you hear it?
look for worn spots or debris or something imebed in a tire.
Describe the thump better. Does the car shake move with it at all or is it strictly just an audible noise. You said you can feel a thump. Can you hear it?
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Originally Posted by 99blancoSS
mud on the wheel or lose lug nuts... wild guesses both
look for worn spots or debris or something imebed in a tire.
Describe the thump better. Does the car shake move with it at all or is it strictly just an audible noise. You said you can feel a thump. Can you hear it?
look for worn spots or debris or something imebed in a tire.
Describe the thump better. Does the car shake move with it at all or is it strictly just an audible noise. You said you can feel a thump. Can you hear it?
It's not an audible noise, it's a thump you can feel but not hear, and the speed it occurs at matches the rotation of the tires.
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Verdad Gallardo Are the tires new? I had a defective side wall once that produced a bulge that accounted for a problem once. Check the tires out real good. I would look at all else before popping the cover off the diff. Sounds like it just happened all of a sudden right? Check out the u joint as well. Sounds like you think its a tire or wheel. At least that would be the easiest solution.
Originally Posted by 99blancoSS
Are the tires new? I had a defective side wall once that produced a bulge that accounted for a problem once. Check the tires out real good. I would look at all else before popping the cover off the diff. Sounds like it just happened all of a sudden right? Check out the u joint as well. Sounds like you think its a tire or wheel. At least that would be the easiest solution.
Dunno how long it's been doing it, this is one of the first times in a while I've driven the car around without listening to music or something.
Well, since it IS a Randy's Ring & Pinion rear end.....must be the muffler bearings going out.
OK, that was for affect. Look to see if your rear yoke is hitting the I-pipe. Mine made the same sound. And obviously when you jack the car up, all the trajecotry changes, so you have to chek it with the suspension loaded.
OK, that was for affect. Look to see if your rear yoke is hitting the I-pipe. Mine made the same sound. And obviously when you jack the car up, all the trajecotry changes, so you have to chek it with the suspension loaded.
Originally Posted by WAHUSKER
Well, since it IS a Randy's Ring & Pinion rear end.....must be the muffler bearings going out.
Northwest Differential is the only rear end shop that has ever done any work on my car..
Originally Posted by WAHUSKER
OK, that was for affect. Look to see if your rear yoke is hitting the I-pipe. Mine made the same sound. And obviously when you jack the car up, all the trajecotry changes, so you have to chek it with the suspension loaded.
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Would be curious to know what you find, seems I could have the same problem as well. Posted something in the axle section asking if anyone might have a suggestion to look but got no responses. 
It could have been there since I bought the car, I discovered it same way you did, turned off the radio for once and could barely hear it. My first RWD car so not to familiar with how things should look so I do what the general public does when they don't knwow hat could be wrong, look and stare and hope you see something that may "look" broken!
Guy I bought the car from is a mechanic and I know he changed a bearing or something in the rear end that was making a squeeking and he said other than the bearing everything else looked fine. After seeing someone suggest the tires it could be what is causing mine, side wall on one of my tires looks really worn (like it was driven with it low... really low...) considering taking the rims/tires off the GTP and swapping to see if it goes away now.
Maybe it is suppose to be there?
It could have been there since I bought the car, I discovered it same way you did, turned off the radio for once and could barely hear it. My first RWD car so not to familiar with how things should look so I do what the general public does when they don't knwow hat could be wrong, look and stare and hope you see something that may "look" broken! Guy I bought the car from is a mechanic and I know he changed a bearing or something in the rear end that was making a squeeking and he said other than the bearing everything else looked fine. After seeing someone suggest the tires it could be what is causing mine, side wall on one of my tires looks really worn (like it was driven with it low... really low...) considering taking the rims/tires off the GTP and swapping to see if it goes away now.
Maybe it is suppose to be there?
Sorry, I thought when we were doing the swap Aaron said your was from his shop.
I would think it is NOT your ring or pinion gear considering your power level & an auto. And spiders usually make noise going around corners. So I would take a close look at clearances. Wheels vs snubbers, stuff like that. Drive shaft vs exhaust is possible, but you said it's the same frequency as the tires, so I'm thinking wheels or tires are hitting something.
Jack it up & put it into drive & see if it gets worse or goes away with rear end position changes vs the car. Then you can crawl under & see if you can find it.....or take it to Dan.
I would think it is NOT your ring or pinion gear considering your power level & an auto. And spiders usually make noise going around corners. So I would take a close look at clearances. Wheels vs snubbers, stuff like that. Drive shaft vs exhaust is possible, but you said it's the same frequency as the tires, so I'm thinking wheels or tires are hitting something.
Jack it up & put it into drive & see if it gets worse or goes away with rear end position changes vs the car. Then you can crawl under & see if you can find it.....or take it to Dan.
Originally Posted by Ryan K
Rear end gears...