Who Can Answer This?

[AWDSR20]

Its “Out of round” and the dealer can't describe it? Go to another dealer!!! ur paying too much already at the dealer, the least thing that they can do is to explain the problem to u, regardless of ur mechanic background!!! Demand an explanation!

[brooster]

I will assume this car has an automatic transmission for now.

First, if you watch a CD spin, that is an example of almost "perfectly" round. Tires are allowed to be out of round somewhere in the vicinity less than 90 thoundandths of an inch. This means, with the tire mounted on the car, the car jacked up, place an object (piece of wood) near the tread. Use something like a quarter to space the wood away from the tire. Rotate the tire by hand. As you rotate the tire, it should not contact the piece of wood. On larger tires such as big trucks, more leeway is given than on small tires such as yours. This is largely a judgement call based on experience in evaluating tires. Hope this helps.

Next, if this car has an automatic transmission, try power braking the car. Set the parking brake. Power braking means to hold the brake pedal firmly with your left foot, place the transmission in Drive, and increase the engine rpm with your right foot. The vibration may occur at 1800 rpm or less. If it does, this is good. Now, we can start to isolate the problem.

From what you describe, I believe as someone suggested earlier, that you may have a problem with an engine or transmission mount, or the exhaust is contacting the underbody of the car. This could be caused by one or combination of the the things above. This could explain why it doesn't always occur.

The car/engine must be under certain load conditions, such as pulling a hill under moderate to heavy acceleration.

[LaDyInReD]

Hey everyone... well i just got a transmission fluid flush and that didn't solve anything... if the problem was with the torque converter, how would i go about checking that? would there be a way of fixing it without having to get a whole new tranny?

Also, how would i go about checking the engine or tranny mounts? i'm not a mechanic and neither is my boyfriend... so if i were to bring it to a shop to have it checked out, what should i say?

Thanks

[brooster]

Ask some older people whom they have used and would recommend for reputable automotive repairs.

Take your car to the shop and tell them that you are experiencing a vibration at approximately 1800 rpm and that it does it sometimes and sometimes it don't. Don't point them toward the mounts. If they know what they are doing, they will find the source. If the car is doing it under load (eg, 1st gear only) tell them that. Tell them everything you can, but don't try to diagnose it for them. If you do that, it will just make it that much easier for a dishonest shop to sell you something you may not need.