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93 F150 vibration-front yoke replacement?

I read through the thread about the 94 4x4 and it doesn't relate to what is happening to my 2wd 93 extended cab. This is a 4.9 liter inline 6. 5-speed manual jap transmission.

I've had this vibration since I've owned this truck, but it used to be my secondary transportation and I just put up with it, but now it's my primary transportation and I'd like to get it fixed. I suspect the truck has been rolled sometime in its lifetime from a dent in the roof, a few body parts have been replaced and a few other things that indicate the truck has been apart at some time.

Most of the vibration is when it's going over 60 mph. I don't feel it in the steering wheel so I would think that it's in the back. So this is what I've done so far.

Balanced all the tires with no effect. The guy at the tire shop said that one of my rims seem to be bent. Changed out all the rims. Exact same problem. I noticed that there was some runout in the tires while they were balancing them.

Talked the tire shop into exchanging the tires expecting that maybe there was a belt separation or something causing the problem. Still the same problem.

Got under the truck and checked the runout in the drive shaft and noticed the rear shaft had probably a 0.2 inch runout. seemed like the rear shaft was bent. The front appeared straight. Took in the whole drive shaft and they said the front shaft was bent but the rear was straight. They repaired it and replaced the three u-joints. He also indicated the front yoke was scored and thought this could be the source of some vibration since the bushing where it mounted in the tail of the standard 5-speed tranny was probably worn also.

I put the new balanced and straighten drive shaft in and @#%&^%, still the same @#$$#$@#$ vibration. Haven't had a chance to check the runout again, decided to have a drink instead. Really needed one.

Anybody had this problem before?

Anybody changed out the rear tailshaft bushing in the transmission before?

Anybody want to buy a nice 93-F150 that will keep you awake during those long drives on the interstate?

I guess my next step is to change out the yoke shaft and replace the bushing in the rear of the tranny.

Anybody have an old-good splined yoke they want to part with? Anybody knocked out the old bushing before and put a new one in?

Thanks

Dave

Reply to
dave
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Its been my experience that when the bushing in the tail shaft goes bad, the output seal fails on a regular basis. With the right tools, changing the bushing is less than an hours job including R&Ring the drive shaft.. What kind of shape is rear tranny mount in along with the crossmember? I've seen the crossmember on Vans get messed up where it hangs down if the vehicle wasn't put on a lift correctly resulting in a vibration, and I cant remember if it was the same set up on the F150. Was the center support on the drive shaft replaced as well? Have you had a thrust alignment on the vehicle done? What kind of shape is the right side radias arm bushing in?

Whitelightning

Reply to
Whitelightning

Thanks for the reply.

I don't think the bushing is bad, after further investigation. I has about 0.010 of play which according to one place I called is acceptable. I adjusted the center bearing and was able to get the yoke into the shaft another 1/2 inch. This made no difference in the way it acts. The tranny mount seems good and tight, I tried to move the tail shaft of the transmission around with no success. The carrier bearing has not been replaced. It looks intact and theres no breaks in the rubber. The shop that did the balancing of the driveshaft didn't think that it was in need of replacement. Haven't looked at the raduis arm, but will later today. No I haven't had a thrust alignment on the truck.

The vibration isn't rythmic like a tire going around. at 60mph and higher it feels like the drive shaft or something kind of bounces with various levels of amplitude. Don't really feel it in the shifter much and don't really feel it in the steering wheel. Doesn't seem to change if the truck is coasting or under power or when the brakes are applied. The tires don't seem to be wearing bad or uneven.

Could it be something internal to the transmission? For the life of me, I cant imagine anything.

I'm running out of ideas here and the truck is becoming undriveable.

I'm about ready to sacrafice a virg>

Reply to
dave

Pull the driveshaft and have it rebalanced and joint well checked as your problem is likely in that area. They are rarely well balanced from factory and they can get worse with age from rust until they get to a point that you feel them.

----------------- The SnoMan

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Reply to
SnoMan

I know you had it checked but you need to check it again andall parts of it because you are overlooking something. Also, is this truck lifted?

----------------- The SnoMan

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Reply to
SnoMan

Have you check to be sure the drive line is correctly phased? That can cause a big time vibration. It is common after driveline work by someone who is not up on 2 piect drivelines.

Lugnut

Reply to
lugnut

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