Guys with 4.10's

  • Sponsors (?)


I paid a local installer $300 in labor to put in my FMS 4.10 ing and pinion gear this past May 2003. I hated all the driveline slop my car had with the stock set-up from the factory, so I told the installer to "set the backlash as tight as you can set it without getting gear noise." He set it at the minimum stock spec - .008" - and my car has had gear whine since that day they were installed. Thing is, I've definitely gotten used to it, and it's really not all that loud. You don't even hear it with the radio on - even talk radio. Plus, I have noticeably less slop in the driveline, which I think makes my minor gear whine more than a worthy trade. It makes driving daily much more enjoyable, plus it's easier to launch better at the track not that I don't have to worry about the driveline going "CLUNK" as the driveshaft/pinion gear catches the ring gear momentarily after I hit the gas!

FWIW. my installer also used the Ford Friction Modifier along with Ford Synthetic gear oil.

So, if your installer set the backlash pretty tight, I'd guess it would be normal to hear a little gear noise when you are inbetween being on/off the gas pedal (like my car is.) Ask the installer what he set the backlash to when he installed your gears. This might shed some light on why you are getting some gear noise.

My stock 3.27s had so much play that I made the local Ford dealership check the backlash for me. They said it was "within spec", but remember spec is between .008" and .015". Mine was set at .013, which I can tell you is like night and day when comparing .008.
 
I belive my installed went with .008, he told me they were set up tight. He also told me I could stomp on 'em from the get-go. :nice:

I only have some noise when I'm in "throttle purgatory." Not being off the throttle, but not really enough to completely maintain the car's speed.

The only loud whine I get is sometimes when I've downshifted into 3rd gear (revving around 4K), and using engine braking to slow me down.

BTW - 4.10's for life. :nice:
 
GinoGT said:
I belive my installed went with .008, he told me they were set up tight. He also told me I could stomp on 'em from the get-go. :nice:

I only have some noise when I'm in "throttle purgatory." Not being off the throttle, but not really enough to completely maintain the car's speed.

The only loud whine I get is sometimes when I've downshifted into 3rd gear (revving around 4K), and using engine braking to slow me down.

BTW - 4.10's for life. :nice:
I have the same deal. Mine actually didn't make any noise at first but I just started hearing a little whine in the last 2 weeks like you describe here. I just hope it doesn't get worse. I've had the gears in for about 4 months.
 
There should be no whine. Whining almost always means the installation isn't quite right. I've had mine for about a month now and they are as quiet as can be. I'd get it checked right away because the whining may indicate that the gears are wearing wrong as well. Did you "break them in"?
 
Before my gears were installed, I had a bad carrier bearing that made noise, the pitch went up as my speed increased. I don't know how long it was there because I couldn't hear it with the top down all summer ...
 
I was told 1000 miles, and that's what I did.

I didn't go scientific on the break in but I drove it home for like 45 minutes at around 65-70mph on the highway, then the next few days it was raining so I obviously didn't beat on it then.

Like I said, it's not all the time. Just in certain circumstances. Even then it's not enough to drown out my exhaust.
 
GinoGT said:
I was told 1000 miles, and that's what I did.

I didn't go scientific on the break in but I drove it home for like 45 minutes at around 65-70mph on the highway, then the next few days it was raining so I obviously didn't beat on it then.

Like I said, it's not all the time. Just in certain circumstances. Even then it's not enough to drown out my exhaust.
I was told that a safe heat cycle means no more than 15 miles without a 30 min cooldown for the first 50 miles.. Also during break in a lot of metal particles will come off the ring and pinion, which is why you should have changed the fluid at 500 miles .. not sure if you did that part.. a combination of the two can cause whine
 
GinoGT said:
It's not really a "whine." It kinda sounds like some weird type of road noise, that's the best I can describe it.

I totally agree. It's not like it whines like a turbocharger as I ramp up the rpms. It's only a slight moaning (very much like road noise) that occurs in "throttle purgatory." :)

My installer told me I didn't need to do any special break-in and did not recommend changing the fluid after XXX miles. It's been almost 7 months since the install and nothing's really changed. I'm not too worried about it.

I'll probably go ahead and change the dif fluid for kicks sometime over the next month or so. I guess it wouldn't hurt.
 
Any car I have ever done gears on has been less noisy or had less apparent noise than factory.

Heat cycles are very important, you can bake the oil if you drive without heat cycles durring break-in. You'll be driving with some worn lube in the rear unless you did the proper heat cycles. As for changing the fluid, if you didnt bake it to begin with it shouldnt need change. If you did youll have worn gears if you dont get to changing it.