Have an 04 with a 3.55LS, rear gears are howling big time at 67mph with only 10K on the odo. It is still under warranty but since I worked as a mech for Ford for a number of years i am capable of installing & setting gears. I would rather purchase the gear set & put it in myself. Don't want the hassle of taking it back several times to get it done correctly & I don't want to tie up the truck waiting on the repair when I can do it in a few hours. Looked in several after market catalogs, they are showing 9.75 R&P but ratios are in the 4's. I'm thinking I need to get a gear set from Ford in order to keep the 3.55 ratio.

Input or comments appreciated.

Thanks

UPDATE:

Against my better judgement I listened to my wife & took the truck to the dealer to get a new ring & pinion installed. Took them 3 days. When I picked it up & got it to 45 mph the driveline had such a bad vibration the whole truck shook. Trying to explain how bad it was, It was as though the midshift bearing mount was not bolted on to the frame & the driveshaft was whipping around but there was not any noise associated with the vibration. Took it right back. They had the truck another 6 days. I went into the shop after day 2 & they were installing another ring & pinion. Theey said the first one was bad. Huh???

Finally they told me they installed a new drive shaft & to come & get it (this is day 9). When I went to pick it up I slid under the truck to inspect their work before I went into the service area. They installed a rusty used drive shaft that looks like it came from a truck that had 2 northern winters on it & a lot of miles. Also, I keep the truck clean & waxed. There were coffee drippings on my leather seats & it had been driven down wet gravel roads & it was covered in the white chalky residue from those roads.

I confornted the service manager about the problems using strong language but being carefull to avoid swear words. A new drive shaft has been ordered or so they say.

With the used drive shaft the truck still has a driveline vibration but it is minimal & occurs on decelleration between 50 to 40 MPH.

The POS dealer I used was Tamiami Ford in Naples FL.

 

you can look here www.4wheelparts.com but if i remember right i only saw 3.75 as the lowest for the 9.75 or you can google the numbers for richmond or genuin gear or precision, i am sure they make them, good luck

 

Try; http://www.ring-pinion.com/content/p...sp?vid=3&pid=4
They list from 3.08:1 to 4.88:1 for the 9.75

JMC