Tips & Techniques: Driveline (anything between crank & hubs)

[ArdWrknTrk]

Clutches, gearboxes, shifters, coolers, shafts, diffs and axles.
What do you have to share?

[Ray Cecil]

Do you think you have a driveshaft vibration? Diagnose it with duct tape and a few coins or washers.

First, make sure your ujoints are in proper spec. Replace if necessary.

If still vibrating, locate a factory mounted balance weight. If no weights welded or glued to shaft, look closely to see if it came off.

If no weights are present, or no weights have fallen off, take the ductape and make a few wraps. Then take a quarter, or a washer and place it under the last couple of wraps of tape. Drive it. Does it change? Better or worse?

Keep adding quarters, one right next to the other. Eventually it will find a happy balance.

If it smooths out, then you know its the shaft, take it to have it balanced and checked for straightness.

If you never find a balance, look elswhere for mis-balanced rotating pieces. Flywheel? Harmonic dampner? Etc.

[ArdWrknTrk]

I'd also mention if you have a two piece shaft, or two shafts with another joint in the middle, make sure they're properly clocked.

I'll take chalk or a Markal and put a line across, so it goes back the same way it came apart.

[85lebaront2]

Ray, item for you, I was told years ago to use big hose clamps (actually read it in Popular Science in a monthly series called "Model Garage"). I did that on my 1977 F150 after changing it from a 300 with a C4 (not one of Ford's better ideas) to a 390 and C6. I had to shorten the shaft and change the yoke.

The method I used was to jack up the rear axle and place it on jack stands. Have someone run the truck up to the worst vibration, in mine about 45 mph. Using a crayon or chalk CAREFULLY hold it up to where it just touches the drive shaft at it's lowest "swing". Using that reference, install two big hose clamps with the screws opposite the heavy side. Recheck, if the heavy side is now at the clamp screws, move the screws in opposite directions a short distance apart, repeat until the vibration is gone.

On my 1977 it ended up needing 3 clamps all lined up the same way.

[Ray Cecil]

Hey guys, all great ideas.

Ive  never been brave enough to get under a running vehicle with tires spinning just inches from the ground.

The chalk or marker idea to locate the runout on the shaft while the shaft is spinning is genius, you just need to have a pair of balls big enough to do it.

[FuzzFace2]

85lebaront2 wrote

Ray, item for you, I was told years ago to use big hose clamps (actually read it in Popular Science in a monthly series called "Model Garage"). I did that on my 1977 F150 after changing it from a 300 with a C4 (not one of Ford's better ideas) to a 390 and C6. I had to shorten the shaft and change the yoke.

The method I used was to jack up the rear axle and place it on jack stands. Have someone run the truck up to the worst vibration, in mine about 45 mph. Using a crayon or chalk CAREFULLY hold it up to where it just touches the drive shaft at it's lowest "swing". Using that reference, install two big hose clamps with the screws opposite the heavy side. Recheck, if the heavy side is now at the clamp screws, move the screws in opposite directions a short distance apart, repeat until the vibration is gone.

On my 1977 it ended up needing 3 clamps all lined up the same way.

I have heard the same thing on the hose clamps and think easier to move than tape & coins.
Dave ----

[Ray Cecil]

Also, The worm clamp idea sounds like a more permanent solution. The duct tape and coins works, but is meant to be temporary, just good enough to drive around until you get to the shop that can balance/straighten it properly.

[ArdWrknTrk]

Oh no.
Chalk or marker is to keep the alignment when you take them apart, in order to keep from causing a big imbalance.

Though I see how you are thinking.
I have done that on pulleys and such.

[Ray Cecil]

Jim, Bill mentioned chalk to locate the shaft run out.

I digress. The hose clamp idea is way better and if you have hose clamps, you should use them. But if all you have is duct tape and a quarter....well....there you go.

[ArdWrknTrk]

Sorry Ray.  

I said chalk or markal.
Bill said chalk or crayon.

I got confused.

[85lebaront2]

You're within your rights to be confused. My two piece rear shaft has a master spline on the slip yoke so it will only go one way.

[ArdWrknTrk]

That's good to know.

Thanks for 'schooling' me Bill!  

[85lebaront2]

No problem Jim, that is what this site is about, knowledge sharing.