3.73 or 4.10 gears

[Visionlink]

Today I called our local gear shop to order an upgrade to MM 3.55 gears. After learning from you I requested the 4.10 gears. I was told to upgrade to 3.73...slower out the whole, but it's better for HWY driving and will last longer. That's only one jump from the stock gears. If that's the case why bother? He also mentioned how tedious it is to break in the gears. Requires incremental driving...8 miles, 25 miles, 100 miles etc. and let gears cool after each increment. Comments?

[Local Boy]

Don't know who you are talking to...but...You are right 3.73's is not worth the trouble...don't do it...

4:10's is the way to go...Alot of us have them...and have no problems...as long as it is installed correctly...pinion depth and backlash is very important to get right...or it will be noisy...

4:10's will raise your RPM's just a little (non issue)...this puts your motor closer to it's power band, making it a rocket when you stomp on it...It will also lower your mpg's by @ 1...

Also, there is no break in time for rear gears...Just install / put fluid and friction modifier / and go stomp on it...

Your comment on the advice given you regarding gear break in, makes me suspicious of that person's experience...I would not use them for my install...Besides, saying that one gear ratio will "last longer" is ridiculous...Bad advice again...In short, Gear ratio has NO influence on longevity...

Do yourself a favor and take it somewhere else...

Get a tune (from one of our vendors) and 4:10's you will thanks us later...Trust me ...I did...and I'am still thanking these guys for steering me this way...

ALOHA

BTW: My car is an absolute ROCKET...with these mods...

[Mike M]

I have never heard of that in my life. That means every new car coming off the production line has to be broken in...NOT

Go somewhere else...this guys is on drugs.

[Visionlink]

My bad. I just did a search on gears and found a massive amount of info. Sorry to waste your time. Your search engine is the bomb. I will order the 4.10s and no break in required....man that guy sound like he knew what's up. Came recommended. Anyway, you guys are what car ownership should be all about...what a team. Thanks again.

[MarauderTJA]

Go with 4.10's. I don't know what this guy is talking about.

[fastcar]

If you don't do much highway, and don't give a rat's @#$ about gas, I'd even go with 4.56s.

4.10s raise RPM 15%, 4.56s 28%.

fastcar

[mdskiing]

Make sure that the flange that the drive shaft connects to the rear is as close to perfectly round or else you will have vibration/noise.

I expereiced that this week at Dennis' shop. He fixed same.

[Blackened300a]

There is a break in but nothing like was mentioned. For the first 500 miles you should avoid WOT starts so the gears can get a wear pattern.
After that you can do what you want with them.

[oldekid]

Find a speed shop that the Mustang guys go to. They will be good at changing out gears, because they do it almost daily. That's what I did, and I was totally happy with their work.

If they are good, they will suggest a break in period. It seems like a long time, but is the right thing to do. And yes. . . go with 4:10s.

After that. . . . . . . enjoy!

[larryo340]

Back in the day when I put Richmond 4.57's in my Mopar there was an initial brake in (in the instructions) with the rear tires off the ground for like 30 or 40 minutes in drive at idle, then let cool down for I think about an hour. I followed the instructions, and never had a problem with them even with me beating the snots out of the car.

[fastcar]

I went easy on them for 1 tank of gas, then started racing them. Nary a whisper, or whine... I would'nt worry about the heat up, cool down every 10 miles or whatever some say. Just don't beat on them for the first 300 miles, and you'll be fine.

Also no vibration at 136 MPH, even with stock driveshaft.

fastcar

[Local Boy]

I must have been lucky, twice...Did smokey burn outs right out the shop...with the Bronco...all the way home...4 tire burn outs on dry pavement and 10 ft rooster tails in the sand all day long the next day...Nothing...smooth...quiet ...Still throwing 10ft rooster tails without a peep from both axles...been in for @ 5 years now...Love the sound of a 4 wheel burn out...Just can't be matched...

With the MM...Stomped on it right out of the shop also...Went WOT from start at the next corner...did that every day after that...not a peep...been in for a year now...just beautiful...

I probably put a wear pattern down in @ 20 minutes...the way I was beating on it...LOL

ALOHA

BTW: Still working on posting up pic's of the Bronco...This computer stuff is TRIPPY...LOL

[larryo340]

I must have been lucky...Did smokey burn outs right out the shop...with the Bronco...all the way home...4 tire burn outs on dry pavement and 10 ft rooster tails in the sand all day long the next day...Nothing...smooth...quiet ...Still throwing 10ft rooster tails without a peep from both axles...been in for @ 5 years now...Love the sound of a 4 wheel burn out...Just can't be matched...

ALOHA

They would have to be making alot of noise to hear over the tire hum I assume

[sailsmen]

Call another shop he is full of crap or an idiot or both.

I have over 85K on 4:10 and over 180 runs.