casperorr

About 5 weeks back I had 4:10's installed in my 2007 GT. I had a very dependable shop install the gears, and they have a very good history. Actually, their name says it all = AMP Performance = All Mustang Parts and Performance. Driving my GT home after the first install of the 4:10 gears, I noticed right off a noise at low RPM's andcoming to a stop. It sounded like = CLACK CLACK CLACK. That is the best I can describe it. I would have taken it back immediately but I was their last customer for the day and they were already locked up and gone home. So, I continued home being very careful not to over heat the new gears for I had a long ride home = over 100 miles. After contacting the shop they wanted me to bring it back and have them test drive the GT with me. They were very helpful and didn't try to bull**** me in any way. Only problem, they have no 4:10 gears in stock, and would not have any for at least 4 weeks. They use only Ford Racing Parts. So, I drove home after onlybeing there for approximately 30 minutes or less. I really hated to drive it much more for the noise was getting louder, or so it seemed. 4 Weeks come and the gears are in, so I made my appointment and returned to the shop again for the third time. Being by myself, I waited the 7 hours or so in there waiting room. Again, I was their last customer for the day, and I actually waited in their shop with the doors locked, for they were not done and had to work a little overtime. Ready to go home was all I could think about, so finally done we went for a test drive. The shop employee drove the car and I was the passenger. I could hear the noise still but it was faint. I was told to drive it a few days and the noise should go away as the gears mesh and break in. Well, approximately 20 miles down the road on the way home the noise got louder and louder to the point I felt very uncomfortable continuing home, but the shop was closed and I could reach no one. By the time I got home, it sounded like some one was in the trunk banging a hammar. Got home with no breakage.

Sorry for the long story, but I felt I needed to tell everything so you could understand the depth of the problem. Calling the shop ASAP, I was told that they have been doing way to many re-installations of the 4:10 gears, and that they were having trouble even getting the gears. Something that they have never experienced before since they have been in business, and they have been around for many years. So the verdict is that the Ford Racing Ring and Pinion set is faulty. The tooling or something during the process of making the gears was off. So I am again for the 4th time next Monday taking my GT back, but this time it will stay and the manager will drive it after the install for a couple of days making sure it is right. In the event that the next set of 4:10's turn out the same results, the manager would like for me to choose to either install 3:73's or return the GT to stock putting in the original 3:31 gears. They have never experienced anything wrong with the 3:73 gears. He didn't mention anything about 3:90's or 4:11's.
One other choice he offered me was that he could change out the complete works and put in an auburn (sp?, not sure it is spelled correctly)setup. He claims this is a very good upgrade anyway, and that this type of upgrade would normally cost about 1500.00 dollars, but he would only charge me for the parts and no labor, so my cost would be approximately 400.00 dollars more then what I have already paid, which has been approximately 800.00 to date. That would make my total right around 1200.00 dollars.
SO, What do you all think about this? Does this upgrade sound like a fair price? Is the auburn and gears better than 3:73's and my factory limited slip unit?
They are being very helpful and cooperative, and in no way excusing anything. I am sure it is not the labor at fault here. These guys are very good at what they do and they mainly do mustangs (99%), hence the name AMP Performance.
Has anyone on the forum had simular experiences with the 4:10 gears? I find it hard to believe that all 4:10 gear sets from Ford Racing Parts are bad. Do they not inspect their products? I am sure that this problem has been brought to the attention of Ford, but with everything else that I have been reading about Ford and their quality like the "Front End Thunking Noise", and other very obvious problems that seem could be easily fixed, I don't know what to think anymore.
Well, I hope that I have not put you allto sleep, sorry for the long post. I just wanted to make sure I explained it as best I could. I will keep you updated on my progress as well as the solution.

Thank you,
Casper

v6 mustang

Not sure about the auburn set up, but I have been told the the 3.73's are pretty good, but it is all in what type of application that you are looking for. I am looking @ putting in the 3.73 my self and possibly looking @ AMP doing the job. I have had them work on my other mustang and felt they did a good job. Do some background work on what would better suit your Mustang and go with it.
FYI-SVC motorsports is another good place to have work done on your stang. They are out of Scottsdale and do a good job too. 480-998-8885 is there #.(www.svcmotorsports.com) Give them a call and ask some questions, it is always free...Hope that everything works out for you.

S281 E

3.73 would make you happy. I assume you have a 5 speed, I would think the 4:10's wouldn't be that great with a 5 speed.