CBSTANG

I have a 05' Mustang GT, auto, with minor bolt on mods. The next step I was considering was to swap my gears for 3.73's, so I call the dealership where I purchased the car, and asked them how much it would be for them to install them if i bought the gears somewhere else, and they told me that they wouldnt even install them, because It messes with the speedometer and other things. I have a diablosport predator tuner and can adjust the ecu after the swap, but im not sure that that is all that would be needed to for the car to function right. Also, I dont know who to try and call to get my gears swapped out, I live near Omaha, NE so if anyone knows of a professional that would do this please help.

dragonfans04GT

Look in the phone book yellow pages under auto repair. Look for driveline or drivetrain repair. You can also ask reputable transmission shops who they recommend to work on rear ends. Everybody in the town I live in recommends the same old guy, so that's who I went with.

spyder7724

yeah i agree find someone who has a lot of experience. i also will warn you that the 05-06 mustangs have an issue with gear whine. i have an 06 gt auto with 3.73's. i have changed gears twice trying to get rid of the noise. it seems that the carrier(posi unit) that ford put in the new mustang is the same casting that they used on late model explorers. they had a terrible problem with gears and noise. i found that while checking the backlash i could get different readings as i rotated the ring gear. this is not supposed to happen. i guess ford found some way to keep them from making too much noise from the factory i.e. some weird backlash setting( idid not check this before i disassembled mine so i don't know what it actually was set at) they also filled the panhard bar with sand and added big nblocks of cast iron on the axle tubes to dampen the noise.

that's a lot of trouble to go through to try to use up all of the bad carriers they had! my advise is if yours makes noise after the gears are in, get an eaton or auburn posi unit and replace the piece of crap ford put in there.

wadman

Im not sure why people arehaving so much problem with gear whine. I have ford racing 4:10 gears with no noise at all. There is a lot of skill involved in setting up gears right though. The guy who set mine up had to shim them about four different times but he got them perfect.

spyder7724

what i found while setting these up was the carrier ford used on the mustang/explorer 31spline 8.8 is not machined properly. it's one of two things either the holes for the ring gear is not centered on the carrier or the face where the ring gear mounts is machined on an angle. this is the only reason to have a backlash that varies as the ring gear turns. i have found on another message board that people that do not experience this problem are the exception. it sucks and it's annoying. i've been doing this for years and have done approx. 50 8.8 rears and never had anything like this. i was going to buy another carrier on ebay then i noticed all of them were take outs from explorers. guess i'll tear it apart again this time it gets an eaton posi unit and maybe 4.10's.

tradetheoex

I had 4.10 installed in my 06' automatic GT and I have no noise from them. I picked up almost 1/2 second in 1/4 mile time from the gear swap alone. Next mod is a SCT XCAL to improve shift firmness. My Diablosport Predator has no provision for shift firmness adjustment, contrary to all the advertisements.

RobD

tradetheoex, did your trap go up/down/stay the same? TIA

GJP05

Check the regional section someone has already asked this question there.

CBSTANG

Thanks for the help everybody! I really appreciate the input. I will post what happens with my car later on, thanks again.

promustanperformance

I recommend looking for a performance shop that deals a lot with Mustangs. Also, Ford Racing gears are highly recommended. Installing gears correctly is not an easy thing. I read one of the posts here and someone said they didn't check the backlash before disassembly, something that has to be done for proper shimming. Have it done right the first time. Good luck

Sincerely,

Michael Clark
www.ProMustangPerformance.com