Help with trans(?) diagnosis

[ChallengerHK]

Saturday I was getting ready to go to a Christmas party. I thought I might take the Challenger, so I fired it up, let it warm up (in neutral) and went to get some gas. As soon as I accelerated I got a rhythmic "whoomp" sound and the car seemed to repeatedly accelerate and hesitate in about 1/2 second increments. I did a u-turn and coasted back home.

Checked the trans fluid level (motor warm, in neutral), and it was a little low. I added fluid to it, and that only seemed to make it worse. The fluid I added didn't even seem to register on the stick as long as the motor was running.

Any ideas? Trans roached?

[tactransman]

First off , get the transmission full in neutral and drive it , post results.

[ChallengerHK]

First off , get the transmission full in neutral and drive it , post results.

TTM - In general I don't have a problem with that, but I was concerned that it was showing fluid UNTIL I started adding, at which point it wouldn't register. Is this something you've ever heard of?

[tactransman]

If you have it running in neutral, you just have to add fluid till it's full then if it goes off the stick you have a problem (leak?) It sounds more like an engine problem by your decription "rhythmic "whoomp" sound and the car seemed to repeatedly accelerate and hesitate in about 1/2 second increments" the whoomp sound isn't back firing is it?

[ChallengerHK]

If you have it running in neutral, you just have to add fluid till it's full then if it goes off the stick you have a problem (leak?) It sounds more like an engine problem by your decription "rhythmic "whoomp" sound and the car seemed to repeatedly accelerate and hesitate in about 1/2 second increments" the whoomp sound isn't back firing is it?

Engine is good; runs like a top, no leaks anywhere. Definitely not an engine sound, not backfiring. It was a very low frequency sound, and seemed to be coming from right rear in relation to me, but with practically no interior sounds echo all around the inside of the car.

I'll try another quart of trans fluid and see what happens. And see if the rest has already leaked out somewhere.

[moper]

That's a new one on me...It doesnt do it when coasting in nuetral? Only under power? Did you have the parking brake set the last time you parked it?

[Carlwalski]

I would try to top the fluid up again, it may not help that noise but perhaps the fluids did rise then sink due to heat and running, it may have been real low? Similar to a radiator when you top it up....rev it a little to get it at running temp....it drops down, fill her up, drops down, then fill her up - good to go.

Not sure, just throwing some coins in the ring. Good luck with it and I hope you find and fix the source. 

[ChallengerHK]

Busy last night, but hopefully I'll give it some attention tonight.

[MEK-Dangerfield]

This doesn't sound like a tranny problem from here. Believe me, I know a slipping tranny.      The brake suggestion sounds right to me. Maybe one is grabbing in the rear. This is all based on your statement of the engine running like a top, so I eliminated that. Please tell us if you find out more.


  Mike

[ChallengerHK]

I thought about brakes, and if I don't find anything else I'll pull the rear wheels this weekend and check for leaks there.

[ChallengerHK]

Did some work and some diagnosis this weekend. Made sure the trans was full, and I think I can rule it out; no metal flakes, no bunred smell, seems to be bahving OK. I took it out for a test drive to try to diagnose, this time in an open parking lot with the windows down so I could listen.

There's is definitely a rhythmic noise, coming from the front right, I think. It matches vehicle speed when I'm accelerating or coasting, but it goes away when I put the brakes on. I pulled the wheel and checked the caliper, which seems to be a little tight but not that much, and the bearings, which I had just replaced. Couldn't find anything that was obviously wrong to me. Any ideas?

[MEK-Dangerfield]

A warped rotor? I could see in my rotor that it was hitting in certain spots, and skipping others. The noise would go away when I hit the brakes too.


  Mike

[ChallengerHK]

I was noticing that my disc was a little pitted, so I guess that could be it.

[moper]

Swap tires right to left, try again. If the noise doesnt move, dig deeper. Bent spalsh sheilds can make a noise if a rotor hits them, and I've bent them without even noticing before and put stuff together. IMO if it's a thumping noice that goes away when the brakes apply, it's probably not the brakes. It's something that touches or connects to the brakes. What does the tire tread from that side look like? Worn even, or worn more towards one side or the other?

[ChallengerHK]

I've barely put 1,000 miles on the car since the new engine a couple of years back, so the tire tread is all fine. I do know that the front is out of alignment, but assumed that if anything there was the issue that it would have been making the same noice before I replaced the bushings.

Next opportunity I'm going to pull the caliper, sand down the mating surfaces and make sure it's greased. Worse case scenario, I'll be able to eliminate the caliper from my list of culprits.