Here's an easy fix for the 2003/4 stiff ride and stinkbug look. Remove the 2nd shortest leaf from the rear springs. It is easy and free. Install 2001 axle bump stops ($12.00) and add a set of 2 inch drop shackles ($49.00). You'll have a truck that is within 3/4 of level and rides MUCH better. The rear suspension will be about the same as the front in stiffness. There's a small tapered shim between the axle and the spring pack. It sets the pinion angle. Order and add another one to each side to improve that angle. The FPPK spring kit from Ford ($175.00) includes both the 2" drop shackles and 1 inch shorter front springs that also improve the ride! Purists may argue that I have weakened the leaf springs resistance to windup under heavy acceleration. Maybe I have, but not to the point where it is noticable. If you spend you weekends at the strip, this may not be what you had in mind. But if you drive in the real world of potholes and train tracks, you're going to like it.

 

If I understand you correct you added another shim to the other side which would then set it to zero, so why didn't you just remove the shim altogether?

For my two cents I love the ride of my '03, and yes I lowered the rear to within a half and inch with the JLP 3" shackles. However I don't have anything to compare it to so maybe ignorance is bliss. To each their own.

 

The spring shims have an angle of about 2 1/2 degrees. If you stack them, you get an angle of 5 degrees. I have not done a precise measurement of the new pinion to driveshaft angle and the tranny to drive shaft angle yet. I'll do that tomorrow and report the results here. The goal is to make both those angles the same. They don't have to be perfect, because everytime the suspension moves, the angle changes and the u-joints make the system work. My guess, in looking under my newly dropped 2003 Lightning is that the tranny to driveshaft angle is about 2 degrees and the differential to drive shaft angle is about 5 degrees. As such, I want to add another 2 1/2 degrees to the pinion angle to get 'em closer. I'll post exactly how many shims and what the part number for them is tomorrow.

 

I was just looking at that myself and you confirmed it! But, as you also stated it may be more prone to axle wrap. Let us know in a few weeks how everything is.

 

My solution 01 springs with 2" drop shakle =

 

My solution is Hotchkis.

 

I said I'd report what I learned about the shims on the springs that set the pinion ange. Here's the word..... When you put drop shackles on , you actually raise the back of the spring. Doing so rotates the differential so it points slightly downward. The 2003/2004 springs come with the tapered shim already bolted on as a part of the leaf spring assembly. 2000/2001 springs do not have the shim. I turned mine around, so the thick end was toward the rear of the truck and the pinion angle is now as close to perfect as I can measure it.

Net result: vast improvement in ride, no noticable change in traction. Do I plan to change back? No, not a chance. The 2001 springs are being returned to the dealer and the leaf I removed from the 2003 springs went into the trash bin.........

 

kerno,

What does your rear tire to fender gap now measure?

 

whats all this axel chit talk ?

i just today put the 2 inch drop chinga on my 03, will i make it down the track?

 

Don't worry. With 2" drop shackles you should be just fine. It's when you go to the 3" drop shackles that a person tends to run into pinion problems. Worst case scenario is for a two inch drop you would just remove your shim if you have a '03 or newer.

BTW from what the guru's say, aka Tim Skelton, you should get an alignment done also. I was glad that I did. My front was out enough that the alignment dude stated that I would be lucky to have gotten 10-15k out of my fronts. BTW he also said that out of all the L's he has aligned over the years, nine out of ten are out enough to classify as moderate to severe. In short get an alignment. Good luck.

 

That is what my 04 ended up needing. After trying 3 positions(stock, reversed, removed), removing them yielded the best results.


kerno,

What does your rear tire to fender gap now measure?

 

I was gone for the weekend , so I missed the question about fender gap until tonight. I'll check it in the morning and let you know.

 

After removing one leaf and using the 2" drop shackles, the distance from the fender opening to the top of the rear tire is 4 inches.

Kerno