allcarfan

Hey everyone. I have a nasty hum from my front end from 40mph on. I threw my angle tool on my pinion and on top of a C...and on top of the greasable/adjustable ball joints. Im no expert, but it looks like these measurements are off? Mods: adjustable long arms, adams driveshaft, prorock 44. 35.7" measured tire. Total lift of about 3.5". All parts installed by and aligned by a reputable shop. Does this look right or am i measuring wrong? I know what the dynatech website says for the angles, but i dont know if other mods come in to play.

nthinuf

Is it a brand new pr44 install, or it's been there a while and just the vibes are new?

Is it the regular or the unlimited housing?

Post the alignment printout that the reputable shop gave you. I'd kind of like to see that before we start jumping on just how far off those angle finder numbers are.

allcarfan

I wasnt aware there was an unlimited vs regular housing. Whats the difference? Working on getting the prntout for alignment. The loud hum (no vibration) actually started when i had the adams driveshaft installed. That was when i was on a d30. Wheels, tires, bearings, and front axle were all changed....still get the hum.

Note, looks like driveway has a 3 degree slope

nthinuf

https://www.dynatrac.com/downloads/P...20FAQ_revK.pdf

The regular pr44 (and stock front housings) have 6 degrees separation between caster and pinion. (4* caster = 2* at the pinion) The unlimited housing is designed for lifted rigs and has 10 degrees separation (8* caster = 2* at the pinion)

Which way is the ground sloped? (is that pic 7* at the pinion, or 13*)

allcarfan

nthinuf

So if this were level ground, the right side of the pic would be be lower, which would shift the needle 3* to the left, correct? So, 7* at the pinion.

If my admittedly weak math skills are working, with a corrected housing (10* separation), 7* pinion would be 3* Caster. (though your other pics are showing, what, about 17* caster? Or 14* after removing the slope?)

Either way you look at it, as 3* Caster through separation math, or as 14* Caster on the angle finder, it's not really close to the 6-8* range suggested by Dynatrac. Which brings us back to the alignment printout...

I seem to have misplaced my angle finder, but if I come across it I'll snap some pics at both of those spots on my PR44 and see how they compare.

allcarfan

I will be going to the shop that has worked on my hotrods for years. They will put it on a level lift and check for me. I will report back with measurements

nthinuf

Sorry, I just re-read your earlier post. I was thinking driveline vibes due to bad caster. But you said No Vibrations, and there is a 'hum' that started with the installation of the double cardan driveshaft.

So, some other possibilities for the the hum might be a driveshaft that isn't balanced properly (threw a weight, damaged in shipping, not balanced properly before it was shipped, whatever. I want to think that this would cause vibes though), or maybe a problem with the flange/yoke swap when going to the new driveshaft (which might be negated if the pr44 came with the gears/flange already installed?)

TheDirtman

Take to an alignment shop and get a proper measurement

TheDirtman

from the photos it looks like you have too much caster. Lengthen the upper arms.