Front Drive Shaft grrrrrrrrr findings so far. . (2 Viewers)

[concretejungle]

So i just picked up the shaft. I talked to the guy for a little while about this shortening thing. He was kinda an ass (one of those old grumpy men type) but i explained how i was informed by man in the know that this is very unusual. He agreed, and said that this is only the second time in 30 years of building drive shafts that he has had to shorten one. He said usually you need to lengthen it.

We put it on at the shop and had him bring the fork lift out and lift the front off the ground allowing the suspension to droop. At full droop the slip yoke only pulls out about 3/8 of an inch. I have not had time to get out on the highway at speeds to see if this fixed it. I'll know tonight and try to post up pics and results (i do have a hot date tonight, so the driveshaft is not important right now). If not i'll post tomorrow.

 

[sleeoffroad]

So did you measure the shaft flange to flange as well as the truck.

 

[concretejungle]

So did you measure the shaft flange to flange as well as the truck.

Before or after? Either case i didn't. THe driveshaft guru did, and i had him measure 3 times.

When we put the shaft on, we marked the position of the slip yoke with a paint pen, then when we lifted it with the fork lift we measured the slip. Only 3/8 inch.

 

[sleeoffroad]

Can you take a picture of this? 3/8 inch what?

 

[concretejungle]

Can you take a picture of this? 3/8 inch what?

Yes, i will take a pic this evening. I was saying that the slip yoke pulled out 3/8 of an inch when we let the axle droop fully compared to sitting on the ground.

 

[Tools R Us]

Yes, i will take a pic this evening. I was saying that the slip yoke pulled out 3/8 of an inch when we let the axle droop fully compared to sitting on the ground.

That sounds correct, have you measured your rear flange to flange?

 

[concretejungle]

That sounds correct, have you measured your rear flange to flange?

No, but i will for a data point.

 

[concretejungle]

UPDATE:

So, it's exactly the mother fawking same! grrrrrr and all! Damnit!

Here are the pics i said i would take. And the measurement from rear output flange to flange on rear diff is right at 38 inches.

 

[concretejungle]

Last couple.. ..

As i was laying under the truck a minute ago cursing, i may have had an idea Perhaps i'm not feeling the vibration with the front shaft off, because when letting off and on the gas it's not torqueing the front axle, therefore it's not pressing and releasing the tie rod onto the control arm. Look at the last pic.

 

[sleeoffroad]

If your tie-rod is touching the control arm you could certainly get vibrations into the cab. Also the axle wrap can cause it to touch more, so yes, that could be the issue all allong. Gring the arm to get more clearance and it should be ok. However did you not have the noise/vibration before fitting the caster plates?

 

[concretejungle]

Christo, thanks for hanging with this thread.

It's kind of embarassing to admit, but i really don't remember if i had it before vs. after the plates. I think i had a little vibration. I have had the castor plates on for about 3 months. It seems that this grrrrrr has been most noticable over the last month. I also think that as i ponder this situation, i am noticing it more now because i am doing a lot of highway driving. Before i was just driving around town. I can't believe i didn't think of this before.

I will grind the arm down a little and see what happens.

 

[Cruiserhead05]

Weird,

We both seem to have the same GRRR issue but i am having no problem with the tie-rod touching a control arm. Hmmmm..

 

[sleeoffroad]

OK, here is a little bit of common sense that people can use when fighting this. If the noise is u-joint/lift related, it should change as the height of the vehicle change. So like Brandon that runs heavy suspension and no front bumpers, strap a 200/300lb pig/sandbag/girlfriend/boyfriend/wife/dog to the front/rear end and see if the noise changes or goes away. If it does, it is a pretty good indication that is is driveshaft/ujoint related.

Unfortunatelly shortening the driveshaft was jumping the gun a little. Based on the photos you posted, your driveshaft is now 1" to short.

 

[Cruiserhead05]

Christo,

As concrete said, thanks for hanging with this thread.

First, sorry havent update the sig line but i do run a front ARB bumper but no winch, i will try to find something heavy to put on the front bumper and see if it helps. Also, i have replaced all my u-joints, with no change at all....
Hope that helps christo.

 

[Cruiserdrew]

A bad pinion bearing can make the same off throttle buzz. Do you know the service history of your truck? That would be a possibility. Before you panic and spend any more $ on guessing, I would find a friend with a double cardan front shaft and run that as a trial. If that solves the buzz, you'll know what to do. If you live anywhere near Northern California, you could come by and try mine. Your front shaft looks short-what's up with that?

I had the same issue with the caster plates and tie rod interference on the leading arm but got the clunk only going over speed bumps and the like-any short sharp bump would do it. I ground about 1/8 off the leading arm and it's much better. Definitely a PIA, though. I think it's a secret ploy by Slee to sell more of his leading arms, which I'm currently saving for.

 

[Taz]

have you tried pulling your rear shaft?

 

[Cruiserhead05]

Drew,

After doing the u-joints my gut is thinking it might be the pinion bearing or the tcase output shaft...im not sure.
Also, if it was one of these as you mentioned above why would lifting it make the grr come alive.

Also, if this helps, about a year ago i had my 80 in the shop for a low hmmm that acted the same as the grr......coming and going with light pedal pressure. It was bad on the highway. Now, the shop as able to resolve it, they said my pinion seal was done, it was leaking out on the third, replaced the seal and everything was fine until the lift.

Thanks, B

 

[Cruiserdrew]

Hmmm....On the older Cruisers, a leaking seal is often one of the signs that the pinion bearings are worn and allowing some ecentricity of the pinion itself. That causes the seal to wer faster and then leak. I don't know about the 80 series trucks. I hope it isn't your t-case output, that could be expensive. Any metal flakes on the magnet when you drain the oil?

The pinion bearing is really not a big deal to replace-pull the diff, buy a bearing kit from Cruiserdan or IH8MUD vendor, and have it rebuilt by a differential shop.

I still think you are having angle mismatch problems of the tcase output and pinion flange. Keep working with the good folks at Slee Offroad-they will know more than anyone about solving this.

 

[concretejungle]

Is there any test to confirm a bad output bearing on the tcase or the front pinion?

I wish i could borrow a double cardan shaft, but i don't know anyone close with one. I will try and find the time to take the arm off and grind it.

Service history on my truck is unknown before 100,000 miles. Since, i have replaced the front pinion seal (it was leaking) repacked front birfs with new everything, M1 synthetic in front diffs, center diff, tranny, rear diff and motor.

 

[Cruiserhead05]

No metal shavings here. I will keep a close eye on this thread and try my best to add some weight to my front end this weekend....time to find some sandbags.