I'll put a tape measure on each side tomorrow and see what I've got.

 

Wheelbase measures 121.25 on one side and 121 on the other. The fact that the rear wheel looks too far forward in the fender makes me think the rear springs might be the problem. Scotty can you measure your rear springs for me? Bushing to bushing. Thanks.

 

Measuring straight across the top from center of bushing to center of bushing is 43 1/2".

Doing the same but following the curve of the spring is 45"...... Roughly

 

Mine measure 44" exactly with the weight of the truck resting on the wheels. I suspect that the arch of the spring is the only difference. Not sure what's up with my drive shaft but the simple fix seems to be to re drill the leaf spring pin hole and move the axle back about 3/4".

 

Are you talking about re-drilling the hole in the axle perch? Not sure that will be good for the springs to have the load off-center. Have you tried shoving the engine/trans forward?

 

Ross because the trans 'locks' into the cross member I can't see a way of shifting the drivetrain forward. You bring up a good point though I need to look at the trans mount, if it's not symmetric perhaps it's installed rotated 180 degrees.

On the F3 there are 10 or 11 leaves in the rear spring pack, it'll do just fine with the spring perch shifted 3/4". It's basically a solid mounted axle

 

The transmission mount is symmetrical, the rubber block that is bolted into the bottom of the transmission crossmember will fit either way. If your wheelbase is not 122", I would say that the rear axle mounting is the problem. You might check to see if the spring center bolts are sheared and the axle is moved forward.

 

Everything looks great as far as I can see with it all assembled. I'll take a better photo, this is the only one I have at the moment.

 

Here's mine right before the trans and diff swap. Notice the rear part of the shaft slip joint is toward the front. Yours is toward the rear.

Not that it matters. The shop that did mine put it on the rear like yours. My point being, maybe the PO had a repair or new shaft made and measured wrong? Didn't allow for slip joint?

 

Plenty of possible reasons for the problem but I think that as the wheelbase is obviously short by about an inch that I should correct that to solve it. Thanks for all the help.

 

Not really, Better to put it back the way the factory intended it to be. You start changing something to out of spec it just snowballs. Much more likely it is just the wrong driveshaft or possibly tranny. I can take a look at it Sat. Are you going to retain the OEM rear end (for parades or pulling stumps?) and tranny?

 

I went back in the thread and see that you say the DS is pre-loaded by an eighth of an inch. Is it possible that the slip joint has been over-greased, and simply can't compress enough? I've heard of people pumping in grease until it becomes a hydraulic cylinder, and first time a good bump is hit, it blows the tranny mount or the splines apart. Easy enough to pull the spline apart and clean it out. It only needs to be lightly greased.

 

This might help:

 

Ross, I'll pull the grease zerk out and see if it will compress any more.

Chuck, I checked the dimensions and everything looks to be normal (tape measure accuracy) except for the wheel base being roughly 3/4" to 1" too short. The frame does not appear to have been altered, the spring mounts look to be stock and the trans cross member appears to be stock. The wheelbase difference could be related to the front or rear axle placement. I do not know what is original on this truck and what might have been changed. The rear springs appear to be 'stock' using Fatfenders measurements. The consensus is that the trans is the stock type trans and the trans mount is not a factor. It bothers me that the wheel looks too far forward in the fender opening which leads me to believe that the wheelbase error is because the axle is too far forward in the chassis. It will be great for you to take a look over things when you are here with Gary. You've certainly spent way more time around these trucks than I have.

 

I don't think that will do it, the zerk is in the splined area. Pull the splines completely out and clean out the inside of the tube.