So tomorrow I am having 4.10s installed. I'm leaving my car at the shop overnight becuase they're really booked up (not alot of shops in my area). I had to set the appointment for this installation 3 weeks ago and this was the first available date.
My question is, is there a break in period for gears? Do i need to drive a certain number of miles before I step on it?
500 miles is the deal. When you get to 300, start to get on it a little, not like a raped ape though. Go to the powerband progressively with first and second (up too 5000rpm, it's OK) That has worked well for me everytime I broke-in gears. No whining or failure yet.
I was told to take it easy for 2 or 3 heat cycles, and then not to worry about it. Don't see anything wrong with being more careful like Pascal says, though.
It's the hard pull that hurt, not the reving as much. All my experiences are actually with 9" rear, so I might not be a good advisor... I figured the physics are the same on a 8.8
10 heat cycles!!! I asked the same question to my gear guru's and the answer was 10 heat cycles. Also they said that they shouldn't whine at all and the cycles add life to the gear and allow it to "set" properly.
I gave it 12 full cycles in about 4 days then got on them like a MoFo. No problems so far.
_____________________________
05' GT: FRPP 4.10'S, JLT CAI W/ 93 OCTANE TUNE, O/R X PIPE, UDP'S, CMVD PLATES, LCA'S
first off, great gear choice! i installed my 4:10's with the help of a buddy....i would definitely recommend Ford gears only(not motive) and use the specific weight lube designed for your car....you can get this at any Ford dealership and the 1/4 oz break in fluid...as far as the "break in", 500 miles is a bit much.....I drove mine in "heat cycles" for about 200 miles while going through different rpm ranges.....avoid the desire to do on off the line shot(and this will be hard) until you are confident with the set up......i have had mine for a while and have no problems...i love them(except i need better tires.lol) the difference is night and day......i am sure bama doug has sent you the tune forthe gear swap....wait a while(200-300) miles and go have fun....
Heat cycle = completely cold drivetrain (ambient temp) --> drive to normal operating temp (engine, trans, and rear end) --> back to completely cold again.
Each cycle is mixed city highway driving with no hard launches and normal shifts (if manual).
I you get the install done and drive 500 miles then go home you have done 1 heat cycle and your gears will need a lot more breaking in before they can take 5k lauches.
_____________________________
05' GT: FRPP 4.10'S, JLT CAI W/ 93 OCTANE TUNE, O/R X PIPE, UDP'S, CMVD PLATES, LCA'S