U Joints and PM (1 Viewer)

[Uluabob]

Hey all,
Half banana mechanic question here. So I am going to be having my U joints replaced (going OEM). I have intermittent vibrations at various speeds and RPMs post 3" lift (Icon Stage 1), and have done the Delta FRAs and panhard bracket. So question is while doing the U joints are there any other parts I should have replaced at the same time while in there? My truck is 96 on 33's with original gears, with 199,000 miles on it Thanks a lot! and Yes I read through much of the u joint hsitory but didn't see it specifically addressed, thanks!
Uluabob

 

[Railwelder93]

Not really any ‘while your in there’ parts for a u-joint replacement, because nothing is really coming apart. I suppose you could replace the driveshaft bolts if you want, and give the slip joints a shot of grease.

 

[enox]

if you are pulling the propeller shafts, id just say have them balanced while replacing the u-joints. Paint em and grease em.

 

[tacocat]

3” lift. Driveline vibration. I say cut to the chase and purchase a DC front driveshaft.

Replacing u-joints is a simple job, but at the same time one of the hardest to do physically. The physical difficulty is amplified if the joints have never been replaced or if one does not have proper tools.

Paying some one to replace and balance your stock front drive shaft vs buying a @landtank shaft will result in a minimal price difference and you may still have vibrations.

 

[wakesetter]

3” lift. Driveline vibration. I say cut to the chase and purchase a DC front driveshaft.

Replacing u-joints is a simple job, but at the same time one of the hardest to do physically. The physical difficulty is amplified if the joints have never been replaced or if one does not have proper tools.

Paying some one to replace and balance your stock front drive shaft vs buying a @landtank shaft will result in a minimal price difference and you may still have vibrations.

Agree UJoints can be a major hassle. I'm a decent Mechanic and my UJoints kicked my ass. I beat on them, cut them, heated them and cussed them out. Finally just took the driveshafts in and had someone else do it. Sure was nice and quiet once finished though.

 

[Uluabob]

3” lift. Driveline vibration. I say cut to the chase and purchase a DC front driveshaft.

Replacing u-joints is a simple job, but at the same time one of the hardest to do physically. The physical difficulty is amplified if the joints have never been replaced or if one does not have proper tools.

Paying some one to replace and balance your stock front drive shaft vs buying a @landtank shaft will result in a minimal price difference and you may still have vibrations.

Thanks for your and everyone's input. So I have been thinking about this and have some questions. With stock drive shafts and a 3" lift is there any travel room left on the shafts or are they at the extended range of travel and can't extend any further? Does this lack of travel mean they could separate while being extended offroad? Does this issue cause the need for the DC shaft? I called a local drive shaft shop and they didn't really want to touch the truck until I had a local 4x4 "expert" assess the whole truck configuration with the lift, tire size, shaft angle and length etc. etc. He didn't want to talk balancing until knowing that the geometry essentially is correct. Here I am thinking getting the U joints done would be easy
Sorry for the dumb questions

 

[jonheld]

Thanks for your and everyone's input. So I have been thinking about this and have some questions. With stock drive shafts and a 3" lift is there any travel room left on the shafts or are they at the extended range of travel and can't extend any further? Does this lack of travel mean they could separate while being extended offroad? Does this issue cause the need for the DC shaft? I called a local drive shaft shop and they didn't really want to touch the truck until I had a local 4x4 "expert" assess the whole truck configuration with the lift, tire size, shaft angle and length etc. etc. He didn't want to talk balancing until knowing that the geometry essentially is correct. Here I am thinking getting the U joints done would be easy
Sorry for the dumb questions

It has nothing to do with slip yolk length and everything to do with universal joint working angles after the lift and caster correction to avoid driveline vibrations.

 

[Uluabob]

It has nothing to do with slip yolk length and everything to do with universal joint working angles after the lift and caster correction to avoid driveline vibrations.

OK that's what I thought from reading threads on here, but I don't fully understand why? Butt hat's why I was so confused by the driveshaft shop guy's response, I guess then does the stock shaft to U joint angle still work with a 3" lift?

 

[jonheld]

OK that's what I thought from reading threads on here, but I don't fully understand why? Butt hat's why I was so confused by the driveshaft shop guy's response, I guess then does the stock shaft to U joint angle still work with a 3" lift?

When you lift the suspension and correct the caster of the front axle to compensate for the lift, the front pinion rotates down. This increases the driveline angles beyond operating range. This is extremely common with lifts in the 3"+.
Having just gone through this exercise myself with a 4" IronMan lift, before proper caster correction there were no noticeable driveline vibrations. Once I added the proper caster correction using Delta Vehicle System radius arms, I had vibration at highway speeds in certain conditions. A double cardan front driveshaft from Tom Woods solved this.

 

[wakesetter]

Anyone have a link to a new DC to correct this issue? I'm getting ready to add spacers to my front springs, and I have a feeling it might put me over the edge.

 

[Uluabob]

When you lift the suspension and correct the caster of the front axle to compensate for the lift, the front pinion rotates down. This increases the driveline angles beyond operating range. This is extremely common with lifts in the 3"+.
Having just gone through this exercise myself with a 4" IronMan lift, before proper caster correction there were no noticeable driveline vibrations. Once I added the proper caster correction using Delta Vehicle System radius arms, I had vibration at highway speeds in certain conditions. A double cardan front driveshaft from Tom Woods solved this.

I was afraid you'd say this! *Writing message to Landtank*
So just a front DC is needed, not a rear too?

 

[on the rocks]

I don't know that a front DC shaft is a MUST with a 3" lift. I have a 3.5" lift running 20 years with the stock untouched front shaft. I have always fought the rear and the adjustable upper control arms are the best thing you can do there for 3" if you in doing the U joints (rear). If money no issue sure dive in because you will eventually likely have an issue with the front DC.
If on a budget I would do caster correction, upper rear control arms and your U-joints.
I'm not up on the caster correction mods but I also wouldn't modify my axle to make these work. I would suggest getting the correct front arms here personally. Just my .02, to me it's more of a band aid or budget driven but went the correct front arm mount from day 1 so haven't had to deal with it.

 

[Railwelder93]

Just put some u-joints in man, don’t over think it.

If you need a DC shaft, then you do, and if you don’t, you don’t.

 

[tacocat]

Just put some u-joints in man, don’t over think it.

If you need a DC shaft, then you do, and if you don’t, you don’t.

He stated he was a half banana mechanic though.

 

[jonheld]

I was afraid you'd say this! *Writing message to Landtank*
So just a front DC is needed, not a rear too?

What @Railwelder93 said. If you are lifted now with proper caster correction and you don't have vibrations, then move on. The only reason to get a DC shaft is to limit vibration in the driveline.
Nothing needs to be done in the rear with a mild lift other than a panhard lift to get it a bit more horizontal. I am firmly against any adjustable linkage that keeps the axles in place. If you are prototyping and dialing in the suspension and making adjustments as you go, that's one thing. Other that that it just becomes a liability. I've seen them fail on multiple vehicles and it's not fun.

 

[Uluabob]

Just put some u-joints in man, don’t over think it.

If you need a DC shaft, then you do, and if you don’t, you don’t.

I like that keep it simple!

 

[Uluabob]

He stated he was a half banana mechanic though.

True this, but I am learning every time I work on the truck!

 

[Uluabob]

What @Railwelder93 said. If you are lifted now with proper caster correction and you don't have vibrations, then move on. The only reason to get a DC shaft is to limit vibration in the driveline.
Nothing needs to be done in the rear with a mild lift other than a panhard lift to get it a bit more horizontal. I am firmly against any adjustable linkage that keeps the axles in place. If you are prototyping and dialing in the suspension and making adjustments as you go, that's one thing. Other that that it just becomes a liability. I've seen them fail on multiple vehicles and it's not fun.

Thanks, and yes I have been in pursuit of more "normal" caster post lift with the Delta products installed. I definitely have a driveline vibration and will begin with doing the u joints. And i don't have the time or budget to pursue adjustable linkage or custom suspension, I need plug and play for sure! I think I'll just keep it simple by starting with the U joints and see how it rides afterwards with regards to the freeway speed vibrations! Thanks for the suggestions and advice!

 

[Uluabob]

I don't know that a front DC shaft is a MUST with a 3" lift. I have a 3.5" lift running 20 years with the stock untouched front shaft. I have always fought the rear and the adjustable upper control arms are the best thing you can do there for 3" if you in doing the U joints (rear). If money no issue sure dive in because you will eventually likely have an issue with the front DC.
If on a budget I would do caster correction, upper rear control arms and your U-joints.
I'm not up on the caster correction mods but I also wouldn't modify my axle to make these work. I would suggest getting the correct front arms here personally. Just my .02, to me it's more of a band aid or budget driven but went the correct front arm mount from day 1 so haven't had to deal with it.

Yes definitely pursuing "normal" caster post lift with both Delta FRAs installed and the rear panhard bracket. Gonna do u joints and see how she rides! Thanks

 

[tacocat]

True this, but I am learning every time I work on the truck!

That wasn’t a put down at all. I know it can be extremely frustrating too put in all the work to put in new OEM (not cheap) u-joints just to end up wasting all that time and money because that wasn’t the issue.

When I was a younger lad, I would have given up and left it as is in a state of disrepair and would not be able to accept or diagnose the lingering error. Now that I’m an old fart of a TV Repairman with a killer set of tools, I would have no problem with that level of wasted effort and funds.