Hey guys,

Been driving my 4-speed '65 F100 around a bit finally, and the truck shudders on takeoff, especially in reverse. I had a buddy look under the truck when I back up or go forward, and the front of the rear end pivots as I take off, increasing the pinion angle and binding up the U-joints. He told me this was called "axle wrap". Is this common with these trucks? Is there an easy solution to fix it? As far as I know, the suspension is completely stock.

 

I've been doing research and I get the whole concept now...I'm used to coil spring cars with big beefy Hotchkis control arms! So, do any of you have a favored company to get anti-wrap bars from?

 

What you first described sounds more like clutch/flywheel issues to me.






John

 

I agree, and there may be other factors involved.

The 4 speed trans has been swapped in. According to the Warranty Plate trans code, the truck originally came with the 3 speed T-85N overdrive.

Not only has the trans been swapped, the driveshaft is different, and from what I read in another post, the engine may have been also been swapped.

 

I agree with John. Every manual trans car or truck that I have ever had issues with shuddering at low speed take off either had a warped flywheel or an issue with the pressure plate. I assume this is a low speed issue since your friend was looking under the truck. High speed take off and wheelhop are another issue altogether. More information would be helpful. Have you checked the pinion bearings to see if they are ok?

 

Well, I know the driveshaft was cut and shortened to fit the Toploader in, and a new clutch and throwout bearing was installed (put them in myself). New U-joints were also installed. Flywheel looked okay to me; no readily apparent warping or cracking. New pressure plate as well...and apparently the truck did it BEFORE I swapped trannies, so I doubt it's a pinion angle issue due to a shortened driveshaft. The only constant in this set of variables is the flywheel and rearend. I am experienced in clutch swapping...I've been doing 4-speed stuff for years now!

I never looked to the rearend, though. The pinion seal IS leaking; maybe this is indicative of bad pinion bearings? I'm really not familiar with 9-inch Fords, though apparently I'm about to be!

But my pal Scott, who is immensely knowledgeable on all things automotive, saw the nose of the differential move dramatically when I backed up slowly and him peeking under the truck. I know SOME movement is to be expected, but enough to make the whole thing shudder? Yikes! This is only a low-speed issue, forward and reverse, just when taking off. Once the truck gets moving, all is well!

 

The other component to wrap is the suspension. What kind of shape are the shocks/leaf springs/bushings in. I experienced this trying to cure a loose steering condition on a 4x once, ended up the front spring perch giving under pressure.
Just more thoughts... --Mike

 

I'm no expert on leaf springs, but everything looks very good and solid. Shocks are okay too.

 

So are we talking clutch chatter or springs wrapping up? THere is no way to tell if a flywheel is ok by just looking at it. If its clutch chatter its most likely the flywheel needs to be re-done. If you are talking the rear springs wrapping up are they stock springs or aftermarket and are the spring clamps still in place? How much is it moving and how hard of take off are we talking about.

The stock spring clamps are there for a reason.

Sounds to me like clutch chatter from not turning the flywheel.

 

I thought it was clutch chatter when I first drove it, it was just a really terrible shudder as I got the vehicle moving. I don't beat on the truck, it just happens during normal accelleration...it shudders far worse when going backwards, though.

I never saw the wrap, so I'm not sure. I believe they're all 100% stock 1965 springs.

 

I second the motion! Over the years, any time I had shuddering/chattering, it was always a matter of simply replacing the clutch and turning the flywheel.

 

Well, I might check that the e-brake is not hanging up a bit (dragging the rear shoes on the drums) as well. I would think that might cause a similar problem to what you describe separate from a flywheel/clutch problem.

Axel wrap doesn't sound too likely unless something is broken back there.

 

i had that axel wrap in all my old broncos and built a custom bar to fix them .and now i have a 65 f-100 w/ a 429 c-6 one ton alum shaft and big u joints . when i bought her a few years ago the trans was a three on the tree with cable over drive . did not trust behind big ole 429! clutch chattered bad and worse in reverse and alo had bad axel wrap .chatter now gone with the c-6 but i still had bad axel wrap i bolted the old style slap traction bars the big 30 in lakewood stoped all wrap completely i can now lay 30 40 ft posi stripes in the frt lot no prob! wes




99 diesel 4x4 sb // 65 f-100 429 // 03 ranger 4x4 (wifes) // 69 bronco 4x4 // tube chassie 70 bronco project //

 

G'day mate.

Just a thought, (or two)

Down here in Australia, we had GT Falcons etc., that had wedge shaped spacers fitted to correct pinion angle and better suit it to the increase power being applied.

They were fitted between the spring pads on the diff and the springs. I guess, if it's a pinion angle problem causing the diff to wind up on takeoff, it might be worth knocking up a couple of dummy wooden wedges to try out. If it works, make some permanent steel jobbies.

Also, if the shaft's been chopped, check it's in "phase", that is, the uni joints line up correctly. If not, it will probably result in severe vibration more than anything else, but it could be a contributor to the wind up.

One other thing. Since the drive-line has been modified, have you checked the drive shaft angle?

There are drive shaft angle gauges available.
I've not had much to do with them, but they are used to check the angle between the g/box and drive shaft, and then the drive shaft to pinion. If the measurement is taken on the inside of each angle for instance, they should near enough be the same. Hope you follow me there,,,lol.

Well that's my two bob's worth. Hope that gives you some more ideas. Good luck.

Cheers, Ron.