Driveline Vibration

[SkinnyG]

I hauled 17 sheets of 3/4" birch plywood to work the other day (not sure of the weight, but about max for a 5/6 drop), and the vibration was occurring at a lower road speed.  It ~felt~ reduced, but bringing all the cut sheets home it didn't feel reduced any more.  So hard to tell.

Mine usually starts lightly around 25mph and becomes more pronounced around 45mph, and then pretty much stops after 50mph.

If you can let Vile have the truck for a week, where he can drive it every day, I'm sure it would rear its ugly head whilst he has it.

[philo_beddoe]

I agree.

[SkinnyG]

I had mentioned earlier wondering if it was too much vacuum advance on mine.  I changed the can out for a different one (mine was adjustable, but decided no longer to be adjustable), and today drove with no vacuum advance at all.  No change.

Someone (here?) had mentioned poorly setup gear pattern will cause a vibration.  My truck had a vibration peaking around 62mph with 3.07 gears and the old axle.  I swapped in an entirely new housing with all (and I mean ~all~) new guts and 3.73 gears, and the vibration moved from around 62mph to around 50mph.  That's leading me to believe it's not my rear end.

I still haven't changed out the rear "Precision" brand u-joint to the Spicer recommended by my local truck shop.  They say they refuse to install anything but Spicer because nothing else is precise enough.  It's on my list of (more) things to try.

[Captain Swampy]

Do you have another vehicle to drive? Then you could ask Vile if he would use it as his daily driver until he experiences the vibration, whether it takes a week or two. Maybe offer some gas money. All you can do is ask. I wish I was closer, my wife is exceptional at pin pointing noises and vibrations. I hope you locate it soon.

[philo_beddoe]

Do you have another vehicle to drive? Then you could ask Vile if he would use it as his daily driver until he experiences the vibration, whether it takes a week or two. Maybe offer some gas money. All you can do is ask. I wish I was closer, my wife is exceptional at pin pointing noises and vibrations. I hope you locate it soon.

Thanks Capt. for the reply. Sure wish you and a few others on this site were my neighbor. Brook's truck is coming along nice! Yeah, I think VZ can probably pin-point it pretty quick. He's not the type that loafs around on a Sat., he has a busy schedule. But, he's 20 min. down the road, I'll catch him soon enough. As soon as I have it diagnosed, well, that's half the battle, not knowing is the worst part of it. Like I mentioned before, I believe it lies between the two wheels somewhere.

I'm wondering if I should just have the whole rear diff and axle rebuilt, or looked at anyway. Like, just do it and see what happens.

[philo_beddoe]

Still weird though, on the way home yesterday, shortly after leaving work vibe was there. Then after a couple miles, while at a stop sign and on a hill facing up waiting for traffic to go by, then when i took off it was smooth as a new caddy all the way home.

That tells me nothing is out of balance. But perhaps something is worn somewhere. But what changes causing it to go smooth now and then?

[philo_beddoe]

Ok, dropped truck off at  VZ's place today. Now we just wait for the good news right?! Pray he doesnt tell me i have some $600 rear end problem. She's in the best of hands regardless. I or he will post something soon.

[philo_beddoe]

Picked up truck from VZ today. Well i dont have a $600 rear end problem. Much worse. He gave me a full report, a laundry list of issues i should address. The transmission being the main cause of my problem, i guess. I'm too tired to feel anxiety, just a little depressed when i think of it. I guess over the next year or so i'll address the issues. I decided not to give up, but still may get another vehicle so the truck can get worked on.

[SkinnyG]

Would you be willing to air your laundry here?

[MrFiveOh]

Would you be willing to air your laundry here?

X2 kinda hard to have a 10 page post and not give end result to the issues.

[philo_beddoe]

Would you be willing to air your laundry here?

Lol,,,no- VZ is going to work on what i cant. Probably over the next year or so we'll tackle one little issue at a time.  Although i do day dream of a 2017 chevy truck. But debt is dumb and cash is king!

[kopeck]

I think they just want you to share what the culprit(s) are.

I've been lurking and watching this thread since you started it so I guess I'm curious as well.

Just work away at it one issue at a time.  These trucks are pretty darn forgiving..

K

[philo_beddoe]

Yes, let me get to my laptop, so i can type it out much easier.

Basically, the epicenter is the transmission. How I don't know, I brought the truck to a good tranny shop a while back and they swore it couldn't be in the tranny, that there's nothing in there that "could" cause a vibration. Somehow though I always kinda knew it was coming from there.

Anyway, in addition, there are other factors involved. Such as:

1. The entire rear-end is a little loose, due to normal wear, but no real issues or danger.
2. The dshaft is a little long, which I can have shortened easily enough.
3. I need an exhaust spring kit installed. Which will eliminate any harmonic resonance.
4. My wheels a tucked too far into the body, I need to install spacers and bring them out a little, I'm not changing rims or tires, I love the old man stock look. I hate the redneck supped-up high performance look. That's just my personal preference.
5. I need to install an idler arm. Then a front end rebuild someday, okay now though.
6. New Body mounts needed.

Everything else is pretty good. He stated he ran the truck on the lift with dshaft removed, no load and can pinpoint the worst vibrations coming from the tranny. I am not surprised.
I think VZ said he has another TH400 and possibly a 2 piece dshaft. Although since I just got a new dshaft made, I'd like to keep it. We'll see.

So that's it, pretty much pin-pointed to the tranny, although she shifts great. Oh well. I'll be happy when I'm driving down the road smoothly. May even shop around for a new 4 speed.

I'll keep this thread going as these issues get resolved.

[kopeck]

The transmission having issues is a bummer but nothing on that list is fatal.

Curious about the wheel spacing though, do you have something narrower then stock going on or do you just prefer to get them moved out a bit to a more modern looking stance?  My truck looks very similar to yours, when I was younger I didn't like the wheel spacing now I think it's cool, a by gone period.  Or maybe I'm just a dork. :-)

K

[philo_beddoe]

Just prefer to move them out a bit. Still maintaining the stock look.

Yah, cant wait to change out that tranny! It's all i think about now.