I've got an 06 GT convertible, automatic trans, Brenspeed 93 octane tune, Thumper Cams, FRPP aggressive exhaust, K&N CAI, CDC Shaker, 285x18's on the back, Eibach ProKit rear springs.

Questions:
1. I want to get 4:10 gears installed. I saw an article somewhere in the blogs that said it should cost $200-$300 (labor only) to get it done. I'm getting prices locally (Ann Arbor, Mich) in the $500-$550 range for labor. Is this way out of line or is the $200-$300 not good numbers?
2. Since I got the tune the car really sounds great during heavy acceleration pulls rubber 1-2 and 2-3. I also do a lot of manual downshifting (love the sound) rather than just driving the automatic normally. Can the stock automatic hold up to the increased torque (with the new gears), downshifting, and shifts during heavy acceleration? Currently have 17k on the odometer.

 

It's been a few years since I did some gears but I paid $350 for install and that included the fluids. $500-$550 is high for labor only.

 

Yeah keep looking around for prices. I know most of the shops down here were charging me around $500+ to install springs, and only springs. I almost gave up till i found a little shop that works mainly on Fox body mustangs but they had already done a FRPP lowering kit on an '07 and they were only going to charge me $150. So just keep looking.

 

Ours automatics are tough and can handle the extra torque multiplication of the 4.10's, even if you manually shift it. Change the fluid frequently and add a bigger trans cooler if you'd like extra peace of mind. I have 4.10's, a big stall converter, and a supercharger in my 07 GT automatic. I drag race it at our local tracks in the summer, drive it daily year round, and it has been bulletproof.

 

As long as you are getting FRPP gears, fluid, bearings, everything done for under $750 by a reputable installer you can't go wrong. Seeing as you are in MI and your economy is still poor, you would think they would cut you a deal. That said, don't save $100 only to be upset with the quality and the shop.

 

My friends have gone with "cheap deal" I went with Ford service dept. Mine is still awesome, while some of those friends are living with niosy gears or have had to replace them. Reputable shop is the key.

 

+1. Mine were installed at a Ford dealership. They've done gears in three of my cars over the past 10 years and always done right the first time.

 

No worries about the tranny holding up. New rear end gears do not add anything HP or Torque-wise to the transmission, or engine. The same amount of power is being transferred to the rear end gear, it's just a matter of how that gear uses that power. The only parts that will see any increased stress will be anything after the rear gears....ie axles, wheels, tires. Everything in front of the rear gears will not see any increased stress.

 

+1 on finding a reputable shop. When I had my FRPP 3.73s installed, I contacted two shops locally and went with the cheaper of the two. Needless to say, I paid for my mistake and ended up having the other shop do the second install. The cost at the second shop was just about $400 for the labor and fluids, but it was well worth it.

 

So what fluids are used for these gears? Cost? My brother will be doing the install he is an experienced mechanic bun not in mustangs he specializes in VW and AUDI's but do you need special knowledge or experience to do a gear swap?

 

Can anyone point me on the above to the right direction? Also where can i find a good tru trac for my gears on my 05 GT? Is it really needed on an auto N/A car with bolt ons?

 

Being that I didn't do the installation myself, I can't say this for sure, but I believe you'll need 3 quarts of a quality diff oil, like Royal Purple. American Muscle recommends 75w90 synthetic gear oil. I'm sure others would have a recommendation as well.

 

How many miles are on your car and how do you intend to use it? For every day street with light strip use, the factory trac-lok is a decent unit. The friction material on the clutches will eventually wear out though. If you're low mileage you're probably okay to just reuse it. If you're high mileage you might want to have it rebuilt as part of the re-gear process. If you're rebuilding you can have them use the kit with carbon fiber clutches that was factory-installed on Cobras. I don't have experience with any after-market units so hopefully someone else can chime in with the pros and cons of doing a complete change-out.

 

I got 30k miles!
Can i get the gears now and put them in the factory unit and take them out later and put them in a detroit tru trak? Or would i have to change to a new gear set as well? for the time being i'm staying N/A

 

With the low miles I'd say odds are extremely good that your clutches are still in good shape. Yes, you could install the gears on the stock unit now and then move them later to the detroit. You may actually find though that the stock unit will be fine unless you're really going to be beating on it on a regular basis.