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Discussion Starter #1
Ok PSN here we go with another dilemma. So last night I'm heading to church and on the highway traveling 70. All is going smoothly no concerns then suddenly I feel a slight bouncy feeling, and noticed the bed of the truck rattling like it's having a seizure. Take foot of accelerator and vibration continues, no noticable sounds or other of feelings. I slow to a stop, I see nothing obvious underneath ( granted I want crawling under the truck in my suit). While stored truck was idling normally and no new smells, or obvious fluid leakage front or back.

Get back in truck and take off normally, all starts off well, get up to about 50 and the truck feels like the back is bouncing, guess it looked the music on radio (lol). It's a manual transmission and I also noticed the shifter shaking way more than normal when accelerating, the shaking slows when I let go of the pedal but it's still shaking around real good. Can't get over 50 for great if bouncing off the road. Put on hazards and limped the rest of the way 40mph still feeling bouncy but able to drive and maintain Lane. No pulling to either side either. After exiting highway, had a small trip about 7 blocks to destination and truck was fine, no trouble shifting, no noticable bounce, nothing. However I never went over 30 (city streets) breaking felt normal to, no sounds or dragging sensation or smells.

After service in called into work and decided to limp home at 40mph, as I started through the city streets I could feel the bounce start again, even at low speed now, get on highway and start my hour long journey, only able to get up to 45mph to stay safe, bouncy feeling gets crazy worse if I go any faster. As I'm driving I still feel/see the bed bouncing/shaking, I also hear that the bounce/shaking increases when I accelerate, if I took my foot of pedal the bounce/shake decreases. This was discovered because I have a pair of leg restraints on my duty bag in the rear bench, I can hear the chain constantly while driving and increases in does as I accelerate.

Had my wife drive along side me (took two vehicles because I usually leave for work right after church) she said the truck looks like it dancing in the back shaking it's booty.

Made it home and there is a large Hill before my house downhill slope, took it out of gear and rode the hill down, all felt smooth no vibration or shake. Once home reverse felt fine and parked it. Going to crawl under it when I get home in a few hours but not really sure what to look for.

I'm thinking carrier bearing going out or is dead? But no sounds that I can hear (Granted the truck is loud already though).

Maybe the drive shaft lost balance? (Is that a common thing eyeballs all of a sudden)

Can u joints do this to?

Ideas and input needed and appreciated.

All stock, no mods, haven't pulled anything since I've had her for the past few months.

Last thought I thought maybe tires but would that cause the shifter to shake around like I was running over rumble strips that were 4" high?


Sorry for the long post, just wanted to give as much info as possible to get some good feedback
 

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Discussion Starter #2
Dang autocorrect!
Corrections if your confused

1st paragraph
Granted I WASN'T crawling
Stored=slowed

2nd paragraph
Looked=liked
Great=fear
Breaking=braking

3rd
Constantly shaking

Thanks for y'alls input
 

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sounds to me like you have a seized universal, bad carrier bearing, or a "pregnant" tire that is getting ready to toss the tread.
 

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Check the u-joints, look to see if the balance weight came off the driveshaft, you'll see where it is/was on the shaft, check the u-bolts holding the driveshaft to the diff.. Check lugnuts, look for a bubble on one of the rear tires.....etc
 

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Discussion Starter #5
Ok so I crawled under, dosent seem to be any missing weights from the shaft. Shaking the shaft in the middle and the carrier bearing had lots of play. If im right there should be no play right?

U-joints have no play, tires don't have any bulges, Or deformities.

Going to replace the carrier bearing, and while I've got everything down anyway replace the u-joints too.

I'll update when done but going to have to drive the wife's SUV for now. Need to save money and some time off.

Unrelated question... I know I have v the zf5 Trans but can anyone tell me how to determine if it's the wide or narrow ratio? Was wanting to rebuild it, just to know it's fresh and cause I've wanted to tackle it just to say I did it. I was looking at rebuild kits and they ask if it's a wide or narrow ratio.

Thanks again. Will update later
 

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what year truck?
ZF-42 was used 87 to early 94.
ZF-47 was late 94 to 97
 

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Take a picture of the tag on the side of transmission. Diesels can have both.

The S5-42 ZF transmission is available in both wide ratio and close ratio versions. The wide ratio version is available for all F-Series vehicles over 8500 lbs GVW, all engines (6007), except F-Super Duty Commercial Stripped Chassis equipped with a diesel engine. The close ratio version is available only in F-Series vehicles with a 7.3L diesel engine and a GVW over 8500 lbs. The ratios are as follow:
1st
2nd
3rd
4th
5th
Reverse
Close Ratio
(Diesel)
4.14
2.37
1.42
1.0
0.77
3.79
Wide Ratio
(Gasoline / Diesel)
5.72
2.94
1.61
1.0
0.76
5.24
 

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Discussion Starter #9
Lol no pictures or bring done today. Way to much rain gonna have to wait until Monday. Guess it'll give the PB more time to soak in, giving it another blast today.
 
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