I did a full tune up, plugs, wires, cap, fluids, filters etc. My problem is, and before anyone says torq convertor, when I shift (automatic) into 4th gear, overdrive, at 45 mph, I get a pulsating vibration on the passenger front side, wheels are balanced, no problems with tierods or lower ball joint. tried some lucas conditioner, nothing. I'm thinking that the bands may be wore or burning out. Any input from anyone with these symptoms would be greatly appreciated...

 

Check you vacuum modulator,pull off the line and turn the modulator until the inlet points down, if there is any tranny oil comes out the diaphragm is bad.Then check all the lines to the modulator for vacuum leaks and replace hoses if nec. Also check converter for missing weights or bolts.Are your tranny mounts good??

 

No bands applying for 4th(O/D) on a 440T4, so that's not gonna be it. You say it's coming from the passenger side? My best swag is a bad axle, pass side trans mount, or the 4th clutch is toast.
Do you feel this pulsation in the steering wheel?
Is there any noise associated with the vibration?
What is the mileage, and do you know if it has ever had any trans work done?
Also, if you check the vacuum modulator, be on the look-out for fuel(gasoline) as well as trans fluid coming from it. A ruptured fuel pressure regulator can allow raw fuel into the modulator, causing shifting problems as well as engine problems.

 

I should also mention that I replaced the trans-axles, and the cheapy limited lifetime from advance auto gave me the axles for ABS, which my car does not have.... that is located on the passenger.. maybe the splines putting them in, may have caused some damage??, or even a bad axle, throwing it off balance somehow?? Also, when letting off the accelerator in 4th gear, it stops, when applied, starts immediately. as far as any noise associated with pulsation/vibration at higher speeds, is like a constant low, mumbling hum, if you can imagine that, you can feel it no matter what seat you're in. 157K miles, not sure if it has had any werk at all.. might be original. Thanks for the input, I am greatly appreciated. And looks like I may have some werk to do, or atleast check some things out more thouroghly, I might even need that clutch replaced.. Wish me luck.

 

Try this quick test to determine if it is/is not in fact the torque converter...
Drive it until you feel this vibration, and while keeping your foot on the accelerator, lightly step on the brake...just enough to engage the brakes...not enough to actually slow the car down any. IF the problem goes away, it is the torque converter or an engine miss.
You say the axles have been replaced...did you have this problem before replacing the axles, or did you replace them trying to solve this problem?
Could be a bad/damaged hub bearing, I suppose...could also be an issue with the power steering pump/lines. Cadillac has had some problems with P/S lines/hoses causing a "moan" that can be felt thru the steering wheel, and it sometimes sounds like a bad wheel bearing.

 

It's a good thing you mentioned that, about the braking, I have also did that as recommended early on in the symtoms, and to no avail. It is not a little pulsation, i mean you really feel it. As far as the axles, I replaced them, because when I bought the car, i noticed it needed balljoints, and axles first off, because they wear all tore up, and the rubber boots were just gone, I never drove it with the original axles so i wouldnt know. How do you check the hub bearing?

 

You would be able to hear a bad hub bearing...it will sound like a groan or grinding noise, and it will usually change as you turn the steering wheel a little while going down the road.

Another question, too...
If you leave the shifter in "D"(3rd), and go 45-50mph, do you still get the vibration?

 

ehhh, i havntdone anything new to the diagnosis, however for a brief period of a couple few days, it completely stopped???, Afterwards it started again. Now, only somtimes it does it when i slow down too (letting off the accelerator) at by between 40-30 maybe down to 25 mph. Now I know the Transmission needs to be at a certain temp to be fully operational, and when its warm, i notice it acting up and doing the above problem. I will run it down no matter what.... if anything, i will do the vacuum modulator, maybe torq convertor is bad?? at any rate thanks to everyone for the input, help and concern... Thnks

 

I changed the vacuum modulator, and nada, i have gotten the trans warmed up for operation and when it does that horrible thiing, i stop and put it into 3rd and the problem subsides and quits.... what does that mean, overdrive is screwy? Torq convertor screwy??

 

Now we're getting somewhere! From the sound of it, and the description, I believe the O/D clutches are going out. They can cause a shudder, but ONLY when in overdrive. If you pull it down into 3rd and the problem stops completely, then you have an overdrive problem. It could also be a problem with a bushing for the shaft, or a combo of several things, but it is starting to sound like an internal trans issue. Have you ever pulled the trans pan off to see what it looks like inside? That would be my next suggestion. A properly operating trans would have very little doo-doo(hi-tech term) in it. If there is any really dark(black), nasty funk in the pan, the trans is toast. You will normally see small areas of acc-umulated varnish, but nasty poop is not normal.
hth