Transmission or Engine vibration???

[89LincolnTWNcar]

Ok, ever since I did my HO convo, the car has been shuddering VIOLENTLY when in 3rd and overdrive when the gears are about to change. The OD to 3rd and the 3rd to 2nd are very harsh. The car also shudders when I give it gas in 3rd at like 27 and in OD at like 40. The entire car shakes and I need to know what the heck could be causing this, because this morning when I went to pull out of my neighborhood, the transmission slipped and the car didn't go anywhere. the whole car was SMOOTH AS GLASS before the HO conversion. I'm thinking its the injectors causing the engine to run funky at low RPM, the balancer is shot, or my cam is warped or bent.

[Grand Marquis GT]

Check the TV bushing.

[mrltd]

The injectors won't do jack, except make the car run rich....I'd check and make sure the plug wires are routed correctly. If the cam was warped or bent it would have siezed up.

Also check the TV bushing/cable adjustment.

[Blaze86Vic]

Bad injectors can cause missing under heavy load or high RPMs. I would believe that the problem is not the tranny. But more likely that the ECU does not know how to handel the engine at an extremely low RPM under a heavy load. This can be caused by a bap MAP sensor, or in my case a bad MAF sensor as I recently had to replace my MAF sensor.

[Blaze86Vic]

Oh, MRLTD; I had a discussion at length about the BAP sensor. No I do not have one, nor does my car need one. The BAP sensor was a short lived unnecessary sensor in the transition phase from MAP to MAF. My MAF ECU does not need a seperate BAP sensor because it can infer that reading from the MAF/temp sensor. For almost all MAF ECUs this is the case.

[mrltd]

Ah, OK...makes sense.

As for my injector comment, I meant it as the low RPM stuff. And I doubt it would make the car shudde ras he is describing. It could also be a bad torque converter, sionce it seems t odo it in 3rd and OD, which would both be while the TC is locked up.

[Tiggie]

Ah, OK...makes sense.

As for my injector comment, I meant it as the low RPM stuff. And I doubt it would make the car shudde ras he is describing. It could also be a bad torque converter, sionce it seems t odo it in 3rd and OD, which would both be while the TC is locked up.

Good thought, the Torque Converter sounds like a likely suspect.

[mrltd]

Good thought, the Torque Converter sounds like a likely suspect.

All that non existant HO torque... is too much for the converter to handle...LOL


Actually my 91 Marquis had the same issue. Any low RPM acceleration/light load (ie trying to go up a slight hil)l would get me a horrid shudder until I downshifted.

[Blaze86Vic]

In our AODs that's not how the converter works. The converter does not lock up, the tranny does. There are no clutches or actuating mechanisms in our converters. So in 3rd and 4th, we have a solid steel to steel conection from the engine to the input shaft for the tranny. That connection is allways there, but in 3rd and 4th the clutch in the tranny at the other end of the shaft does engauge. If a converter goes bad then it will show in 1st and 2nd, not 3rd or 4th (if you can get there).

[Tiggie]

My tranny is never in third as 27mph anyway, or OD at 40, so I wouldn't know much about this anyway. Third doesn't come along until about 35mph and OD doesn't come until over 50 in normal driving. That's with 3.08's.

[89LincolnTWNcar]

I changed the plugs and swapped out the 2 bad injectors and its smooth as glass now. So it was the injectors or plugs that were causing the low RPM shudder. Just to let ya'll know.

[gadget73]

Cool. I fixed mine with a new fuel filter. Gotta love simple stuff.