Just got my jeep back after a 4.88 regear and front and rear lockers. Now over about 50 I noticed a vibration. I removed the front driveshaft and it went away so my question is why would the same driveshaft suddenly be causing vibrations after a regear?

 

maybe balancing weights fell off?

 

The fasteners were tight?

How do the u joints feel with the shaft removed?

 

Didn't notice any Shiney spots on the old driveshaft.

 

They feel good, seem to move well, centering ball seems to be nice and tight.

 

Did you, they, mark the original position of the DS in the D30 yoke?

 

Not sure what that has to do with anything really. The D30 yoke with respect to the DS doesn't matter. What matters (& what I think, you are tryign to say) is the relationship of the u-joints at the ends of the driveshaft, and that would only be a concern if they pulled the slipjoint apart on it. What you are getting at only matters if the driveshaft is put it back together out of phase. What should have been marked is both sides of the driveshaft slip joint to make sure the yokes at both ends of the driveshaft stay in the same place in relation to each other.

Did they change the lift at all ??

With the jeep up in the air, does the front axle spin freely (both sides) ? How hard is it to turn the pinion ? Is the pinion yoke loose ? Any strange noises or felt vibrations when turning the pinion ?? Is there oil in the axle ? How are the front axle u-joints ?

I'd think the new stuff was a problem before I went after the old stuff that worked fine before.

 

No change to the lift or driveshaft. I got new pinions front and rear (upgraded to u bolt pinion) I have a spare driveshaft that I will throw in today and check that out. I haven't put it in the air yet but will before I try the spare shafts.

 

Are you sure the new pinion yoke is the correct size ?? Are you sure the u-joint caps are on the joint correctly ??

With u-joint straps, you can sometimes let the caps slide out some on the cross, and that would put the rollers inside in a new spot for wear, and can give noises/vibes until they wear in or wear out, which ever comes first.

I have, personally, always put in new u-joints whenever a yoke was changed out. Not too much money, and it eliminates a variable right off the bat.

 

A few good jumps might fix it- good thinking!

 

Lol

 

But when you post incorrect information, that is what happens....someone corrects you, & I guess you get all butt hurt.

As long as the new yoke on the d30 is the correct size for the u-joint on the driveshaft, it doesn't matter if the u-joint is put in the same way or 180 deg out from before.

What matters is the u-joints on the driveshaft....them being out of phase WILL give vibes.

I can take my DS loose from the front axle, and rotate the pinion 180 deg and re-connect it all day long and I won't get any vibes. I've actually done this before while troubleshooting. But if I take the DS apart and put it back together out of phase & then re-connect it, it'll vibe like a rock song.

Maybe if you can't handle someone disagreeing with you, you shouldn't post on the internet.

And I did agree with you on the bolded part...but it still has nothing to do with marking the d30 yoke. The u-joints will have the same arc of travel no matter how you bolt them up, what can change is the location of the caps on the rollers like I said.


What I don't understand, is why people will just replace parts with new when new may not be needed, just because someone told them to on here to justify their reply. Nothing I have read says a new DS is needed, new u-joints maybe.

How you gonna feel when he spends money on this new DS and the problem is still there ??


I'm trying to help the guy figure out what the problem is, not spend his money for him before all other possibilities are checked out.


.

 

Relax everybody please

 

Don't want to start anything, just wanted some ideas on things to check. I was planning on a new driveshaft anyway mainly because I wanted it which is why I guess I am doing all of this anyway.

With the change in the vibrations after swapping driveshaft I think that is the culprit. Both of them are over 20 years old and have seen better days.

 

It's not you starting anything...someone just got butt hurt when someone disagreed with them. Happens all the time.

As for a new driveshaft, it's your rig, your money, but if you have the vibes now with 2 different driveshafts.....chances are pretty good you'll have them with the new one too....just have to wait and see I guess.

Just because it changed when you swapped DS's doesn't mean it's the driveshaft. It could also be anything the driveshaft connects to, or anything that is only moving when the driveshaft is installed.

There's a lot of things in the diff that could cause it that were messed with during the regear, that you will only see or hear when the driveshaft is installed. That's why I gave you a list of things to check on when the front driveshaft is in the air and the DS is out.

Good Luck.

I'm not necessarily one of those guys Jeep Driver talks about, but I do believe in being SURE of the problem before I spend a lot of money on new parts I may not need. It gets expensive to replace things only to find out the problem is still there.



Just an FYI, people on here & on NAXJA told me I needed a new rear DS to cure my vibes after installing a SYE, so I got one....didn't help. What did help was going against the grain on what I should use for shims. used a shim that was slightly bigger than would normally be used....problem went away. I do have a new rear driveshaft tho.
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