I have a 95 SE that has the sam bucking problem. It occurs between 45-50 mph while my car is shifting into third. My 95 has the 4t60E in it. I also live in NW ohio and get the same horrible mileage. My dad is an enigineering supervisor at GM powetrain in toledo, and last week he had me bring my car up there for some of the mechanics to scan it. There were no codes set. they both recommended that I get my fluid changed as it has 112,000 miles and has never been changed. Just like you I have the problem occur in drive and overdrive. After they scanned my car my dad took me on a tour of the 4L60E assembly line which electrically operates practically the same as the 4t60e to my knowledge. Let me tell you; they make quality stuff, the cameras that my dad has put on the line can detect almost any imperfection. Im gonna go back when they get the 6 speed line in. Anyways, my dad gave me the tech manual for the 4L60e, and while mechanically it does me no good, it does say that The TPS, MAP, MAF, and coil packs all tell the PCM when to engage tranny solenoids and the TCC engagement. Im not saying that is your problem, but I will be interested to see what you discover...so keep us posted and I'll do the same. Also...what mechanic are you using since we are in the same area?

Well i'm not technically using him, only took it to him for his opinion. Canfield Auto Repair on 224.

Would you mind doing me a favor? Count your shifts. I am wondering if this problem is preventing our transmissions from going into 4th gear.

That makes no sense about the harmonic balancer. It can't make noise while the engine is off. I think you need a new mechanic; he'* not feeding you much good information lately, by the sounds of it.

It sounds like you might have found your problem with the water pump though. That'* good. The motor mount and bracket does have to come out, but if you unbolt the mount and lift the engine as high as you can, it'* much easier to slip the mount off. Getting the mount out is the hardest part of the job, after that it'* easy. Book time on that water pump is 3.4 hours, I believe, but it'* a gravy job for us techs as you can do it much faster than that, even the first time. Havadder!

His logic behind it was the rubber would be separated from the pulley. Thus once you shut off the engine and the pulleys begin to come to a stop, part of the pulley would still move, as little as it may be.

However he as wrong about my transmission and seemed clueless to some of my other noises.

Update: The ringing noise was very dominate today so I popped the hood and went to check it out. While hitting the throttle with my hand I listened. It seems to be coming from or atleast near the left wheel well. This is while in drive, park or neutral.

I can easily reproduce the sound now. I hit the gas (usually floor it) for a second and let off. As the RPMs come down you can here the ringing rather well. Any ideas? Flexplate? Something with my suspension?

This noise came about after I did both front struts and my right wheel bearing. I cannot say that that is what caused it as my bad wheel bearing was very loud and may have drowned the ringing out at the time.

I finally got the opportunity to go over sixty in my car and it did shift into overdrive, it also hesitated while doing this. Im still stumped. btw how did you clean your MAF? as for the ringing i highly doubt it would be your struts. Have yoy checked your ac compressor clutch to make sure its not binding at all....it would be more of a grinding noise if it were, just an idea. In the 92 lesabre i used to have, a couple of the ball bearings fell out of my alternator bearing and it made a heck of a winding/ ringing at higher rpms.

If you move the pulley on the alternator and it move about 2/3 of the way it means the rubber on the balancer has broken. Also the pulley should not move without turning over engine by hand, look at the balancer while trying this, if the outside moves and not the inside again the balancer is broken.
Best Regards,
LuckyG

Thanks for joining and posting and all but if you notice this thread is long dead sense 2008..we still appreciate the input very much so feel free to make an intro thread,,