livinloud98

Hey guys I had an 8.8 GT rear installed in my car with a t- lok and ford racing 3.73 gears. The car drives 100 times better then before everything just feels better, I don't know how to explain it. My only complaints is I have a bit of gear whine in two spots.

At 70mph i can hear the faintest noise, its probably normal since its so quiet, but I can hear it and my old rear never made this little noise.

Now the louder one is when I am decelerating, and the car is engine braking. Say I am in fourth at 45mph and let off the gas; the rear starts making a decent noise.

So my questions, should I be concerned? If so what should i do? Ive been reading my backlash may need to be adjusted and then on other sites I read that some gears are just noisy. what do you guys think?

TexasTanker19kilo20

From talking to a local speed shop about getting gears they have told me two things make gears whine. One is improper install and two is the owner not "breaking in" the gears right. From what I was told both things are common, more so the owner not following the break in instructions. Also maybe the fluid used in the rear, it might need a friction modifier or if you used stuff like Royal Purple that has the friction modifier added in. This is just what I was advised of. Take it to a tech who knows rear ends. hope this info helps.

157dB

Did they replace the U-Joints as well?
If not, thats your noise at 70MPHs.
I dont believe its the rear end thats making the noises.

My "rear" was making noises but it was the U-Joints, not the rear end.
New joints, no noise.

livinloud98

the u joints on the drive shaft? where are they located?

TexasTanker19kilo20

Yup, ya need to take it to tech.

157dB

At the ends of the driveshaft?
Tech time for you...

livinloud98

why would my drive shaft u joints be making noise all of a sudden after i swapped the rear end? like i didnt change anything but the rear, I did not touch the drive shaft, besides bolting it to the pinion flange on the rear

TexasTanker19kilo20

Well....you asked a question and got some opinions. Then when asked about u joints you had no clue. If you don't know what u joints are then ok. Most people on here know almost everything about mustangs or have had the same problem. Since none of our advice has helped, it's time to take it to a Tech who knows about rear diffs. IMO

livinloud98

I know the U joints are on the drive shaft I was just kinda shocked Im asking about gear whine and some one says its my drive shaft. many other threads I read say backlash needs adjustment and things like that.

but ill have to get it looked at, whining usually isn't a good thing period, thank you for your input.

157dB

The u-joints noise coming now after the install
could be from the disturbing them from the naturally
installed working angles. They dont rotate around their
bearings. They kinda move back and forth just a little.
When you dropped the rear driveshaft, the working
angles went out the door and you maybe rotated
them past where they have been working since day
one. They no likey that. I believe the needles that
liked their OEM home have been evicted and new unworn
needles have taken their place from a land where there
was no side load of HP.

But thats just me.
Did ya totally remove the driveshaft at both ends?
Did ya mark the flanges before removing.
Its a balanced assembly from the factory...

Try rotating the cobra flange to driveshaft relation
90 degrees at a time and see if the new noise is still there.

More info on this 8.8 install and the procedures followed
is needed to diagnose the problem sans internet...