I have a pretty good vibration in my 97 f150, 4.2, 5-speed, 4wd. It isn't a miss because the truck runs good and I have checked everything on the engine. I have looked at the HB many times while the truck i running and can't see anything wrong with it and the rubber is intact. I pulled the inspection plug off of the tranny while the truck was idling and you can watch the throwout bearing bounce back and forth off of the pressure plate. I haven't had the truck but about 6 weeks and all I know is it had a recent clutch job. I am thinking the Flywheel may be the culprit. You never know about some people's mechanical abilities but I am thinking of ordering a new clutch, pressure plate, throwout bearing and flywheel. What do y'all think?

 

Forgot to mention the vibration is there regardless. Doesn't matter if the truck is in gear, neutral or if the clutch is engaged or disengaged. It get real rough around 3000rpms.

 

I'd pull the tranny out and open up the bell housing for a good inspection before ordering any parts.

If you pull the flywheel, replace the rear main seal on general principle.

 

I have never done a clutch replacement on a vehicle and not changed the rear main. Definitely a smart move if there are any miles on the rig.

 

Does UR clutch chatter when U partially disengage or partially engage it ? U probably have a damaged clutch disc from weight on the input shaft when it was installed with the transmission. If so U will see unusual marks when U disassemble it. I understand all UR problems with vibration started with the clutch install ? Some problems migrate from a piece of metal touching the frame of the truck. IF so look for a loose shield. The hard movement of UR throw out bearing is unusual. If the pressure or the disc are right the throw out bearing will work smoothly and free the clutch touch smoothly. U will waste a lot of time, and money throwing parts at it until U inspect it or get a pros opinion after looking at it. It would appear to definitely be a rotation out of balance problem from damage or defective part/build. A pressure plate/disc usually won't mess around long before it blows apart. It may actually come down to loose bolts.

 

Bad motor mount, maybe?

 

DirtBikeDave, this project has become interesting! Replaced the clutch and flywheel (flywheel was warped) and the vibration is still there!! After taking the serpentine belt off it seemed to make the vibration more of a higher frequency. The rubber inside the HB is cracked up but when you watch it spin you can't see anything and the vibration is rough. Probably going to pull the timing chain cover in the morning and make sure the balance shaft is timed with everything else before ordering a $160 HB. Chasing a vibration is a mechanics nightmare. LOL

 

Can't think of a way the shaft could jump teeth and engine still run. Sounds like UR harmonic balancer is ur guy. Can U find one at a parts yard to try? Did U purchase the truck with the engine rough running vibration problems. It won't hurt to check the timing of course.

 

A new HB is only about 75 bucks from rockauto.com.

 

Didn't get to pull the timing cover but did inspect it and someone has had it off at some point. Probably just order a new HB because the one on the truck is no good from what I have read and heard. The timing cover being off at some point just made me wonder if someone didn't get the marks lined up properly during a timing chain replacement. The truck had the vibration when I purchased it but for the purchase price I am still ahead.

 

You gotta pull the HB to get the front cover off anyway, right?

 

U bought a problem the former owner may have caused. U are at the point of pulling the timing cover. Go ahead and check the timing marks and gears. It is so easy to get there with the HB off and if they are right U know U are on ur way with a new HB. Some times the HB if bad, will just break when U take it off.

 

Just ordered a HB from Rockauto for 85 shipping and all. Going to install it next week. Probably put it on and fire the truck off and see if it cures the problem before tearing into the timing cover. What would the chances of a warped crank be? Never actually dealt with one before but it seems like you would eat the bearings up completely in no time if that was the case. hopefully this problem will be diagnosed and cured next week of a junkyard 4.6 might be the next step!

 

Any kind of damage to the crank inside the timing cover will destroy quickly. The crank, mains-rods break or rods bend. All make noise usually loud noise. U may find the HB has rotated internal or crankshaft keyway. Hope not. Some crack. It is not unusual to find the front of the crank damaged, but usually the HB is loose at that time. U can't get wrong gears to work on a balance shaft but U can put the gear in the wrong spot. This would intail some type of internal repairs. Do U know the former owner so U could ask him. I can't think of a reason to do it but Maybe someone was trying to do something different ?

 

I have pulled the balancer and inspected it. The keyway and front of the crank all look good but the rubber is cracked and "mushed out" in about a 1/2"-1" section. Some of the vehicles we work on will make you wonder WTH where they thinking! So the balance shaft being off it's mark could be possible...hope not, but possible!