1. Home
  2. Ford Mustang Forum
  3. Rear gear change in '91

Rear gear change in '91

I am thinking of swapping the stock 3.08's for 3.55's in my '91 rear end. A friend told be that it's not a good idea because the gears are normally lapped at the factory and if I replace them, my diff is going to howl. Can anybody comment on this?

I am also toying with the idea of replacing the carrier assy. with either a new limited slip or possibly a locker. Is this something the home mechanic should try or am I better off getting a mechanic to do it? Is it simply a tedious thing or does it take special tools?

Reply to
5point0
Loading thread data ...

"5point0" wrote in news:JhSMd.22675$ snipped-for-privacy@news20.bellglobal.com:

If they're installed properly, it's nonsense. I had Steeda replace my gears with 3.73s and an Auburn years ago without any problems whatsoever.

Unless you've got the proper place and tools to do it with, it's more of a PITA than it's worth IMO. If you screw it up, kiss the whole thing bye-bye. I'd opt for a reputable shop to do it.

FWIW, going to a numerically higher gear is a very good thing. I love my 3.73s.

Joe Calypso Green '93 5.0 LX AOD hatch with a few goodies Black '03 Dakota 5.9 R/T CC

Reply to
Joe

I'll agree with a few things and add more.

If your car is normally aspirated, I'd go with the 3.73s. I love mine. Turbo or supercharged? 3.55s are probably better.

There are some relatively specialized tools and measurements required in properly changing the gear ratios. I'd suggest a shop.

RE whether or not to change the actual differential: I've had one of the expensive after-market diffs in mine and I'm now back to the factory unit. It's been rebuilt and had clutch disks added to tighten it up even more. I'm sold that this is the way to go. Yeah, I'll burn it out eventually and have to rebuild it. But I CAN do that. The expensive unit from the other Co. can't be rebuilt. Burn it out and replace it ... very expensive.

Dave

Reply to
Dave Wick

Well.... if your friend replaces the gears, you can expect them to howl.... However, if they are installed properly, there will be no problem. You can either trust your friend or you can trust a mechanic. ne last thing... if you are going to trust a cheap mechanic, you might be better off trusting your friend.

There are good mechanics and bad mechanics...... don't even pretend to think that a good mechanic will be happy with bad mehanic wages.

Reply to
Jim Warman

I agree with Jim fully. Get it done by a reputable mechanic.. and yes, you will pay a little more, but it will last. Btw... check

formatting link
for the gears. Best prices I've seen!

-Mike

-- A happy kid behind the wheel of a 98 Mustang GT Cold air intake FRPP 3.73 gears Steeda Tri-Ax Shifter Flowmaster 40 Series mufflers (self-installed woohoo) Hi-speed fan switch

255/60R-15 rear tires Subframe connectors Aluminum adjustable clutch quadrant

Reply to
<memset

If is a manual 3.73 you'll be starting off in second normal driving and dont't think about going over 100 without screaming. If you have the money have drivetrain direct build it for you and ship it. I had one built using 31 spline and no c-clips shipped for $1100. I has been a few years but it was an easy swap that you can do with a friend in you driveway. I asked and they recommended 3.27 if your going to add a blower. Good luck! Hooked 87

Reply to
Hooked 87

If is a manual 3.73 you'll be starting off in second normal driving and dont't think about going over 100 without screaming. If you have the money have drivetrain direct build it for you and ship it. I had one built using 31 spline and no c-clips shipped for $1100. I has been a few years but it was an easy swap that you can do with a friend in you driveway. I asked and they recommended 3.27 if your going to add a blower. Good luck! Hooked 87

Reply to
Hooked 87

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.