Steering stabilizer/shocks?

[CorneliusRox]

Originally Posted by J-Pipes

I've not checked the rear drive shaft other than trying to wiggle it to see if there were any play. I'm thinking of putting the back axel on stands, and bringing it up to speed to see if I can see any shaking. Also it's one piece shaft, short bed truck. Suspension is stock front and lowered rear, reverse leveled. With Firestone airbags for towing.

If you lowered it, make sure your pinion angle didn't change. If your pinion angle doesn't match the transmission/tcase output shaft angle, you'll get some vibration based on the u-joint phasing.
I'd take the driveshaft to a shop and have them go through it. They'll do new u-joints, and balance it for likely ~$100. I had my two piece done with a new carrier bearing for $200 and it got rid of a weird vibration I thought was coming from the front.

For your air bags, are they just for towing or are they your suspension? If they're for towing, I'd recommend something like this where it removes them from the system when they're not in use.
Daystar Air Bag Cradle Kit KU09140BK

[J-Pipes]

Originally Posted by CorneliusRox

If you lowered it, make sure your pinion angle didn't change. If your pinion angle doesn't match the transmission/tcase output shaft angle, you'll get some vibration based on the u-joint phasing.

I'd take the driveshaft to a shop and have them go through it. They'll do new u-joints, and balance it for likely ~$100. I had my two piece done with a new carrier bearing for $200 and it got rid of a weird vibration I thought was coming from the front.



For your air bags, are they just for towing or are they your suspension? If they're for towing, I'd recommend something like this where it removes them from the system when they're not in use.

Daystar Air Bag Cradle Kit KU09140BK

Just the add on kit for towing. Is lowered by replacing the factory 4" blocks with 2" blocks. Has been that way for probably about 6-8yrs now, this vibration is a new thing, the past yr or so.

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[J-Pipes]

Just crawled under it looking around. While I couldn't get it to shake any, the joint at the slip yoke does look kinda funny. Took a couple pictures, theres a seal looking piece on each cap, on the as its sitting horizontal caps, one side looks nice and even, the other does not. Be a couple days before I can pull it and get it checked out, this look suspicious to you guys? Two pictures of the odd looking one.

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[Red Sleeper]

Pull the shaft, check joints by hand, replace if worn.
You’re not going to the moon, this is a basic drive line vibration.

[dieselbeef]

really jake..all this and you haven't pulled the rear shaft and checked u joints....make up something good if this fixes it..or yer new names gonna be jake shafts.....lol...that's funny

[J-Pipes]

Originally Posted by dieselbeef

really jake..all this and you haven't pulled the rear shaft and checked u joints....make up something good if this fixes it..or yer new names gonna be jake shafts.....lol...that's funny

You just wanna see my shaft! All I can say is it doesn't feel like its coming from the back of the truck!

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[J-Pipes]

Update, had new joints installed in the rear drive shaft and balanced. When I dropped it off, the guy said at least one of them was definitely bad, so I was hopefull. Well, it's better, more inconsistent, and not as violent, but still there. Wife was waiting on me already, but I'm planning on looking very closely at the trans/transfer case mounts. Also have new shocks on the way, so hopefully I can do all of that in the next week or so.

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[Red Sleeper]

Dang, that drive shaft sure sounded like the culprit. I guess the truck is close to 20 years old. Might be time to replace some mounts.

[J-Pipes]

Yeah, just keep reminding myself that for what I need a truck for, I'm many thousands ahead to just keep at fixing this one. Although I do kinda fantasize about finding a 2×4, automatic, rust free roller to replace it! Dont see many ecsb 2×4 around here, let alone rust free. Not to mention my non-existent budget for the venture!

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[95cummins5.9]

I had good luck with putting spring clamps on the leaf springs when I had this problem, the other things that helped was a one piece driveshaft, and aluminum rims with force balance. If I remember correctly, I had like 5k in chasing that wobble. Replaced a ton of crap chasing it.
The spring clamps are in stock at most orielly. Good luck!

[J-Pipes]

Drove it to work today, still shaking. I've known the pinion seal of the front axle was leaking, but haven't thought much of it, fluid level was still ok. Now after looking at it after a 50 mile commute, maybe theres more to it than I'm thinking. These pictures are about 10-15 minutes after I parked. If I can find a 3/8 drive ratchet or breaker bar in work, I'm going to check the oil level again. While parked, with the front driveshaft currently out, I can spin the pinion. Could I secure the pinion from spinning somehow for the drive home, or is that a bad idea? The u-joint caps are still bolted to the yoke, thought about running zip ties through there to something, or just around the axel housing. The housing itself was cool to the touch when I was looking at it.

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[J-Pipes]

Went out and checked the oil level on break, it's still good. Oil seemed a little thin and runny for gear oil, and kinda gray? I did go ahead and zip tie the pinion yoke to the axle so the ring and pinion shouldn't spin when I head home, see if that helps. Is there anything special to rebuilding the differential on these? Just worst case if it needs more than a new seal.

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[J-Pipes]

Made it home from work, pinion is still zip tied, and truck is still shaking/vibrating on the drive, so I'm thinking the front axle is not the source. Trans/transfer case mount looked fine as well. It is definitely speed related, not rpm, so that should indicate it's not engine or transmission related correct? I've got new shocks ordered, I doubt that fixes it, but I'll try getting them on when they show up.

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[Red Sleeper]

New shocks might dampen the vibration but probable will not solve it.
I’m leaning to the wheel and tire side of things. Run your hands around the tread of each tire. See if you feel any lumps or irregularities.

[J-Pipes]

I still need to double check the tires, figured I'd pull them off when I do the shocks. The thing that makes me lean against that though is that it's done this with two different sets of tires now, and I sold the first set and the guy that bought them said they rode smooth? Only rotating items I haven't tried yet are engine/transmission/transfer case, and differentials.

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[J-Pipes]

Oh, what a mess working on this thing is! Got the shocks changed today. Not sure how many tools my boys lost "helping" me, but my wife did snap a pry bar! The end of it hit me in the chest when it went, little sore still. But, as I finished, before I put the rear tires back on, with the axle on jack stands, not chrome one's RD, I ran it up to speed to see if I felt anything. Can still feel something, wife thought the right side brake drum had a little wobble, and she says she could "feel" something standing next to it that she didn't on the other side.
Could it possibly be, as these likely original brake drums have worn and rusted, and flaked over the yrs, that they're now out of balance and be what I'm feeling? The guy I bought the truck from at 90k miles said he'd never done anything with the rear brakes. Now, 12-1/2yrs later, at 203k miles, I've never done them either! Is there anything else besides drums/shoes/springs/hardware I should get while I've got it all apart?
Also, if a mod would like to re-name this thread to something that pertains to chasing a vibration a little better that what I've got, that be fine too.

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[95cummins5.9]

You could check runout on both hubs. I believe it's a 2 9/16 nut. . So maybe a 2 9/16 axle nut socket if they're loose.

Edit. Maybe some hub seals or wheel cylinders while they're apart? Try those leaf spring clamps like I mentioned. They're cheap and easy to install

[J-Pipes]

I'd forgotten all about the spring clamps, sorry. I'm thinking there's something about gm wheel cylinders being an upgrade? If so, what wheel cylinders would i be looking for?

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[thatguy69]

Originally Posted by 95cummins5.9

I had good luck with putting spring clamps on the leaf springs when I had this problem, the other things that helped was a one piece driveshaft, and aluminum rims with force balance. If I remember correctly, I had like 5k in chasing that wobble. Replaced a ton of crap chasing it.
The spring clamps are in stock at most orielly. Good luck!

Whats these spring clamps you speak of?

[J-Pipes]

Also on the spring clamps, where are you recommending the placement? Think each video i found on YouTube so far puts them on differently. I have a thought of my own, but curious what worked for you?

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