foxtrot

Hi I am getting some rear differential whine and it looks like my stock 273 gears are going. I only have 90K and never beat on here. Wondering if anyone else has had theirs go bad at roughly this mileage.

In any event I need a new set of gears and am wondering what manufacture and size to use. I am very dissapointed that the stock gears only made it to 90K or normal driving.

Question:
1. So what size? I want a bit more torque and not hurt MPG?
2. What manufacture set is best? Is there anything that is stronger and require no maintinace other than stock ford gears?
3. I was quoted 5.3 hours of labor which equates to ~$450 in labor is this a fair price and time?

JC316

Hmm, that seems very odd. It might have ran out of fluid or something. Those gears should last for the lifetime of the car. 3.73's will be great. Only a slight loss in MPG, but a huge difference in acceleration.

ct_white_stang

I love my 3.73's..You will notice a huge improvement in acceleration. The install price will very depending on where you are located and how many shops are around you. I paid around 300 for my install.

a_penquin

I know the pain, Im about to do 3.73s and 31 spline axles since mine has the clunk and just started noticing it feels like a tooth is missing in the ring gear. Mine lasted me 127k miles and Ive only owned it for 10k miles. Looked like the prior owner(s) babied this to death and Ive been so/so to her. Labor prices vary from place to place, and theres a big difference if its a dealer or not, but that sounds like a ok rough estimate.

Also is your car an auto or stick? I hear the stangs like 3.73s for manuals and 4.10s for autos, if someone can clear that up for me I would greatly appreciate it.

bigjohn2289

If your going to buy a new gear set to throw in it, I would stick with ford racing gear sets, I have installed and rebuilt countless rearends in everything from mustangs to rangers or explorers. The motive and richmond gear sets that I have used just seemed to be lower quality than the ford racing sets, I don't know what it was about them, but they sure made more noise than the ford racing sets Ive used.

I agree with JC316, your gear set should last much longer than 90K miles, describe the noise its making, when its making it and so on. it might just be bearings.

foxtrot

Yes its a 5 speed. The noise well its a whine and its not to bad until you hit about 40 mph. Its not loud but its new. I did notice it "clunks" when I back up some times and only one "clunk" at that. If I throw it into neutral at 40 mph the whine goes away! So it does sound like differential or drive shaft u-joints to me.

I took it to the shop today (not sure I know to much about them but they seemed honest) and they drove it, then put it up on the rack (with a guy in it) and listened for the noise while it was in gear I beleive. Of course they did not invite me out to listen to it (I should have asked them to but did not have the chance).

I can detect that the whine is for sure coming from the back and my daughter and I each thought it was coming from the opposite side so the middle would be a good guess. I had the fluid changed at Jiffy lube prior to taking it to the shop but did not ask for a fluid sample. I guess I that was mistake #1 of 2 today.

Can I inspect the U-joint just by looking at any play from trying to twist it? Is there any way to determine if the rear is shot other than by opening it up?

a_penquin

That is actually how you check the u-joints. Grab the driveshaft with it in gear and try to move it back and fourth watching the joints for play. If theres movement in the joint, it needs replaced. It sounds exactly what I have with mine, except I have a slight shudder and you can feel as if its missing a tooth or skips while at road speeds.

JC316

If it were the gears, it should be whining regardless if it's out of gear as the rear tires will still be turning the gears. I would almost say that it's your transmission that is acting up. Have you checked the fluid level in it?

foxtrot

Replaced the trans fluid and rear diff fluid today (watched them do it at Jiffy lube) before I took it to the shop. I thought the same thing thats why I had the fluids changed before I took it in. I figured maybe thats all that was needed.

I see your point with the drive shaft disengaged the whine goes away almost completely but I still hear it a little. Now that you mention this your right if the was the rear diff it would not change tone or loudness with trans engagement or not right? Would load affect this sound? Now I am scratching my head here.