36 Ford truck on Ranger

[MercuryMac]

Great minds think alike, guys, and I have the weirdest excuse why I haven't already done the spot welding trick. I put my hoist in too far away from the welder, so I can't reach it. There will be more scheming in my immediate future if I'm going to resolve this dilemma.
A couple of days ago, I was in town, pulling out of a parking lot onto a side street, when the truck quit. I had no tools and not much of a clue as to what happened, Oh and I was dressed up quite nicely. A friend came along and took me to Napa, so I bought some tools and a new electric fuel pump. Sure enough, my new test light told me I had power back to the pump but no noise out of it. It was a beautiful day so I crawled under my truck in my good clothes and changed the pump. If only I'd remembered to buy electrical tape, I'd have been set. The truck started up right away, with the new pump. I silently cursed the other not so old pump for only getting me about a thousand kilometres, [620m].

 

[MercuryMac]

Winter has hit us hard, so I have been tinkering in the shop again. We had 8 or 9 inches of wet snow and the temp hovering around freezing.
I was telling you that I was 99% happy with my driveline vibrations being fixed, well that was a lie, I was only 97 or 98% happy so I changed the pinion angle again. There is no really nice flat surface that is exactly on the same plane as the pinion shaft, so I think I had been measuring it wrong. It was too high in the front, and the torque of turning the rear-end forces the pinion front up a little more, especially if you've taken a leaf out of your three leaf spring packs like I did.
While I was taking wedges out [to change pinion angle], I leveled up the back of the truck. One robbed spring pack was de-arched a bit more than the other, so I made a spacer and tucked it in there.

 

[Old Iron]

Are we ever really satisfied ???
My 33 has a vibration in the drive line too. I think mine is the rubber dampener in the aluminum drive shaft I used out of a '90 TA moving around inside.

 

[MercuryMac]

The driveline shop that made my last shaft was really pushing for me to buy a large diameter aluminum driveshaft [at great cost to me], and solve all of my problems- guaranteed. Now I hear from you, Old Iron that aluminum may not be the 'end all, beat all', so I'll keep trying different things on my old fashioned steel stuff. I haven't checked for bent pinion shaft or transmission output shaft yet. My inner mechanic self tells me my vibration is improper driveline angles, though.
Hotrod magazines are a great place to find cool old car pictures and ---conflicting opinions. I've read two serious tech articles lately on driveline angles. They violently disagreed with each other. One of them is probably wrong.

 

[Old Iron]

I won't use another aluminum driveshaft again. They're just too expensive.
Have you leveled the truck at the frame then check the front to back down angle of the engine and tranny?
At that point check the rear end to see if the angle (up, back to front at the pinion) matches the engine down angle.
You have to level the truck with blocks under the front tires to do this and the weight of the vehicle has to be on the front and rear suspension.
That probably sounds as clear as mud

 

[MercuryMac]

Clear enough for me OI, and I've measured the angles with the suspension holding the weight of the vehicle [even manually bounced a bit to make sure the shocks aren't holding things up wrong]. The engine/transmission is 2 1/2* steeper down than the pinion is up, now, after removing 4* wedges. I agree with you that they should be fairly equal; their plane lines should be parallel, but I'm thinking the pinion twists up a few degrees due to torque on acceleration.
There are people that have very different opinions than us, OI, and it would be easier to scoff at them as Bozos, if I wasn't the guy who has the unfixable vibration problems.
I have not leveled my frame front to back. I'm not sure where to make it level, and I'm not sure it will change the relationship between the tranny output and the pinion shafts.
I welcome your input and anyone else's on this forum, I will sift through it.

 

[joedoh]

the last couple trucks I have built had a driveline hummmMMMMMMmmmmmmMMMMMMmmmmmmMMMMM at highway speeds. new driveshafts, new u joints, finally it came down to pinion angle. since the pinion angle was set correctly (2 degrees down from phased) the only option was to buy a lot of random shims and trial and error. I bought a radio instead. (kidding!)

Also, I found out, there is nothing funny about getting bashed in the funny bone until you're sweating with pain.

words to live by. fools rush in but the early bird gets the worm, and is worth.. two... in...

the... [S



grrrrrreat project!

 

[Old Iron]

On the leveling of the vehicle, since the front of a vehicle is generally lower than the rear, lay boards on the floor under the front tires until the vehicle's frame is level. This will allow the vehicle to rest on it's suspension and the frame will be level.
This will make a difference as to what the angle reading will be on both the engine and rear end.
You are correct in saying the pinion will roll up under acceleration. Once the vehicle is under cruising conditions, the pinion rotates back to it's static position. Don't try to compensate for this.
Try this and see if it helps.

 

[Dr Crankenstein]

Backing Old Iron here...

Leveling your frame gives you a baseline of 0°. This does not change the relationship, but provides accurate up/down measurements because you're working from 0°... not the rake, angle of the dangle or curvature of the earth.

I would level your frame here...

.

 

[MercuryMac]

You've fallen right into my trap Dr. C., that's the only place I can put a level, and the place I'd picked, too.
Most people don't look into the future far enough to see that you won't be accelerating all of the time, so the pinion angle will come down to normal when coasting along. I've been a trucker a way too long to be driving hard all of the time. But, I haven't looked into the future as much as I should either.
JoeDoh, I'm into the 'handful of random shims, trial and error phase', now, and I hate it. It feels like the 'fools rush in where angles fear to tread' time of my life. There's no noise in my vibration so even a radio won't help.

 

[Old Iron]

Do you have the vibration when you're running at speed, put the tranny in neutral and coast?
When does it vibrate?

 

[jfg455]

I know yow have been checking the up/down angles of the shaft but don't forget to check the side to side angles. If the rear is square and the motor and trans are cockeyed it can make the same vibration as the up/down relationship.

 

[MercuryMac]

OI, the little vibration is from 60 km to 80 km [35 mph to 50 mph], more so on acceleration but still there, slightly, coasting or holding back. It's the same as coasting with the clutch disengaged or the gearshift in neutral and the clutch engaged. The motor can be revved up or at an idle.
The vibration seems to get a little better from 50 mph to 70mph, but doesn't go away.
Jfg, the horizontal driveshaft to rear-end angle looks perpendicular but I haven't built a square to measure it exactly. My motor/trans to driveshaft angle is unmeasured, as I went to find my plumb line to line up the motor front to back and transmission, but couldn't find my transit, plumb line kit box. I think I lent it to a neighbour and forgot which one. I never got back to finding an ordinary piece of string. So it's one of my many neighbours fault.
How many degrees can I be off square and still be O.K.?
Oh ya, I measured the level of the frame in the only straight flat area and it is level. My frame can sleep comfortably in a grain auger, as can some of my acquaintances.

 

[jfg455]

How many degrees can I be off square and still be O.K.?

It is kind of like the up / down area. It the rear is zero and you start having 1.5-2+ degrees off on the front it will start to have weird harmonics. This is made worse when you start having lower rear gears (3:73, 4:10 etc) because the drive shaft speed is getting faster. If it is getting worse on acceleration but is still noticeable on coast speeds I would look for something moving like a bad mount, center bearing etc. Or in the pinion angle area.

 

[Skip]

http://ratrodsrule.com/forum/showthread.php?t=32943

A few good drive shaft setup tips here.

 

[MercuryMac]

Thank you guys.
Jfg, I used to think pretty good was good enough, now I'm thinking pretty dang good would be better. I had better get my angles closer to equal.
Skip, I looked at that U-tube before, and think it is the best thing since sliced bread.

 

[Skip]

Have you had the balance on the driveshaft checked yet?

Another thing that is suggested in the Freightliner troubleshooting is to disconnect the drive shaft, flip it over (180 degrees) and reinstall it. This can make it better or worse if there is a slight variation in the components. This can go for the yoke also.

 

[MercuryMac]

This is the second driveshaft Skip. Last year when I took the first new one back to town to a different machine shop, they threw it away, saying it was neither balanced nor really straight. This second one is all new and has a balancing weight on it so I assume it's balanced.
I'm going to try a few more things before I unbolt the driveshaft and clock it around, but thank you for suggesting another trick.

 

[MercuryMac]

So this spring I took the driveshaft off and measured the angle of the pinion flange. Whooa, not one of the flatish surfaces on the rear-end that I've been using to get my pinion angle, are actually the same as the pinion angle. Except where the back tin plate bolts on. If all of the bolts have the same height of heads, you could use that, I guess. While I had the driveshaft off I clocked it 180*, and then used four different holes in the pinion flange to bolt the back U-joint to. Oh yes, I also filed down the hatchet wounds on the pinion flange, so the U-joint will have a flatter surface to sit on. I then put 4* wedges under the springs and roared out on the maiden voyage for this year. Here's pictures of the truck this evening when we got back from the successful trip. We didn't feel any vibration through our seats. There was a little time, at 35 mph, that if you held your finger on the gearshift you could still feel the stick dance. I'm good with that.

 

[DozerII]

Congrats on getting the vibration worked out, now it's driving time.