Procedure for changing diff while in the car.

[machine head]

I've got a 2001 Grandprix GTP and the diff is making a howling noise (most noticable at 40kph). Doesn't seem like a wheel bearing as the noise stays the same when you change direction and the sound is still evident when coasting in nuetral or any other gear. Accelerating lightly and coasting make no difference, however applying the brakes lightly and slightly rolling on the gas makes it go away somewhat.

What's the best procedure for pulling the diff while still in the car? I've got a donor car that I can pull it's diff from first. Unfortunately I have no manual and this is the first front driver I've ever owned.

[16MustangVet]

i doubt its a diff that would be a big time failure as in like fluid leaking likely and car wont move. Id start with changing the fluid and filter I also added a full bottle of lucas addative to mine when i blew the GT trans all over a wet off ramp in alabama. ill blame the diff failure on torque spike from dry to wet pavement turning and merging into 75mph traffic all at once on that one. Just start with fluid, filter and fluid addative. I drove my car 1300 miles back to Minnesota the day after i fixed the trans with no problems since.

[16MustangVet]

after i read your post again what condition are your tires?? you said braking and getting into the gas changed the sound? Still doubt the diff but mines a lot quieter with fresh fluid and the addative.

[machine head]

Tire's have maybe 10% wear, Nokian I 3's. The fluid has been changed every 70,000 km. I've read that the sun gear becomes pitted and worn due to inadequate hardening which can make this type of noise.

Edit: I've found pics on this site to help. Great site!

[16MustangVet]

still think you could use a bottle of lucas for the trans Im not much on miracle in a bottle but im happy I put some in when I did the diff.

[Sabrewings]

still think you could use a bottle of lucas for the trans Im not much on miracle in a bottle but im happy I put some in when I did the diff.

Anything you pour into a tranny at best masks the problem, but it's still there. It never fixes it.

[16MustangVet]

never said I would reccomend covering up a problem, love how people do that crap I simply said it helped quiet and smooth mine out when i replaced the diff in alabama then right after drove it to minnesota the next day. If I had to id do the exact same thing again. BTW since march when I drove to alabama to training then back to minnesota and now drove it to oklahoma for more training since march its had some hard highway miles. Still reccomend the lucas and will add a bottle with every fluid and filter change.