I installed my Western drop shackles last weekend (installed them on the last hole - that's three inches longer than stock but I got a 2 inch drop. Not sure if that makes it a 2 inch or 3 inch drop shackle). Anyway I didn't notice any vibration from driveline angles but since I bought an inexpensive angle gage sometime ago I thought I would check things. Based on a rise to the front of the truck being positive - my transmission is at +3 deg, the driveshaft is at +5 deg, and the rear pinion is at -1/2 to -1 deg. Looks like I need to shim the differential with a 3 or 4 deg shim to get it and the transmission in synch. Does this sound right? Do your run or the mill auto parts stores like Autozone or NAPA usually carry shims or do I need to hunt up a suspension and differential shop?

 

Summit Racing carries them. I bought a set but still haven't done anything with them...

http://store.summitracing.com/defaul...t=pinion+shims

 

http://www.paulshp.com/lightning.htm
(about 1/2 way down page) (not advertisment, this is information)
not necessarily

Shackle Kit - drops back of truck approximately 2" so truck sits level but more important the pinion angle is increased from 0-2° negative which makes the truck hook a lot better. Poly-bushings included with shackles.
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with a negative pinion angle, when you hammer it the axle wrap will go positive, but not as bad as the stock angle would. Lowering the rear actually helps reduce the pinion angle that occurs during hard accelaration and pinion angle changes


Mine is dropped 2" in the rear only and I have no pinion angle shims

lowering the rear plants the rear end

 

Just turn your stock shim around and you'll get 4 degrees. The stocker is a 2 degree, from what I've been told.

 

I-menace - I'll probably show great restraint and try to preserve my factory warranty (at least for awhile) so drag strip action probably isn't in my immediate future (well, maybe a couple of passes ). I just want to keep things nice and smooth and not give any reason to the rear pinion bearing or transmission bushing to prematurely wear. MHMCGILL - I see a shim or something in there but it looks flat from what I can tell. I need to get it out and mic it. I found a place that sells shims so I'll pick some up tomorrow and see what I can do. Thanks guys

 

just turn it around you should be good to go.... I put 2 inch bell tecks on my 03 and had the 20 mph vibration... so I flipped the shims around and the vibration is gone...... on a side not I hope the pinion angle is ok....... but no vibration so I assume it is..

Doug

 

I'll probably check out reversing the factory shim first, assuming that reversing it won't pitch the nose of the diff. down more. Thanks for the suggestions.

 

Let me now what you come up with

 

I get vibration now at 60mph or so.

I have the JLP 4" shakles, JLP Traction bars. It sits DEAD LEVEL.

I have a harley truck though.

 

I dropped mine approx 3 inches which makes the angle look straighter.

Should I flip my shims also to get a little more angle back.

 

May need a little more information on flipping the factory shims. I had about an hour this evening to mess with it and I loosened the U-bolts on one side and jacked the spring off of the axle. The shim didn't come loose so it is apparently made up as part of the spring assembly and may even act as one end of the spring assembly bolt - like a big washer. Sure would be a lot easier to cram another shim in there since I don't want to have to pull the springs completely out and partly dissasemble it. Of course I lose about a 1/4 inch of my drop then. Anyone got any suggestions on this?? Couldn't get up high enough to see if there is a nut on the top of the spring assembly bolt under the top retainer plate. If there is I guess I could remove the U-bolts and top plate, loosen the assembly bolt, jack the spring slightly off of the axle and try to spin the shim around. Then hope I can get it all back in alighnment again. Any help would be appreciated.

 

The shim does come loose. I watched my alignment guy do it. He just gave it a big wack. There is a locating pin from the axle that centers the shim. Sometimes it can be rusted in there a little. It's just like taking a rotor off. You might want to spray some WD-40 up there and let it sit. . Good luck.

 

Do a search on this board and NLOC... there is a real good how to some where.. I think it is on the harley board actually...... DOug