Well guys, took the truck in and they found the Oasis report and took the truck into the back. I get a call later and they said I'm hearing vibration and not the "rear end humm" they attributed it to the truck being lowered and changing the drive shaft and pinion angle. They suggested taking it to the lowering shop and installing an angle shim for the rear. Has anybody ever needed a angle shim after lowering? When I took it to the lowering shop last week they said an angle shim has never been needed after a lowering job? Its mostly for lifted trucks. Should I go ahead and have them try to install the shim or do you think the buck is being passed at my expense?

 

When lowering of lifting, driveshaft angles will be changed, I say shim it and take it from there. Yes I have heard of shimming when lowering.

 

I got rid of the whine in my factory-height 2X (3.55LS) by reversing the stock shims. The factory driveline angle is too great at the rear and not enough at the tranny. Whining is generated at the input bearing in the axle. Ideal setup is equal, opposite angles at the front and back end of the driveshaft. Take a look under the truck and compare the rear angle to the front.

 

Hmmm wonder if this would work for a 4x4??

 

Capt JJ... any updates???

 

Waiting on authorization for whole new rear end assy!

 

OK but how we I go about getting that? Do I have to fight with my service advisor?

 

Let the shop perform the SSM I told you about, drive it, if it doesn't fix it take it back to the dealer, tell them it isn't fixed, let them re-diagnose it, thats when you should start mentioned getting a rep or engineer involved. Luckily I have pull at my dealer to get things done with Ford. Don't know how other dealers are these days.

 

Ok guys, I just got back from the lowering shop and had them install a 4 degree shim in the rear and the growl is GONE!!!! I am so happy my baby is no longer sick. I hope this will be the only problems for a while. Good luck with the rest of your warranty claims.

 

What is an SSM????

 

Special service message

 

So that means hooking my truck up to Oasis?

 

OASIS is a computer that the svc writer or technician inputs your VIN number into the get information. BUT STOP THE PRESSES, I check SSM's this morning and they have pulled the SSM that said to replace the driveshaft and says another fix is in development. I guess the engineers guess a fix once again only to get in influx of calls saying they didn't fix jack!

 

Capt JJ,

Keep us posted as you hear things. I want to get rid of this annoying whine!

Jag

 

Don't know if your question has been answered yet but!

When my SCrew awas a week old, I installed Bell Tech lowering shackles. They threw the rear end angle off just a tad, which caused a harmonic hum at speeds between 45-60.

I had no clue what it was, and since it was under warranty, didn't care too much either. After about a week of highway driving at the new driveshaft angle, the universal joint "wore in"
and i have not had the noise since.

But I've also read that reversing the axle shims already in place will re angle the drive shaft perfectly, and no more harmonic humming.