Finallyverted

i hello I have had a pinion seal replaced
At 50k now the pinion bearing is making noise I use a mechanic I trust
But really unsure why at 50,000 miles this would go bad?
When I replace the bearing he has asked if I was going to
Do gears I have wanted to do 3.73 but am very new to the upgrading seen for mustangs and to rwd what should I buy and kits needed to help this issue out? Currently have a black 03 gt convertible just purchased as well, PLEASE HELP thanks in advance 😳

cliffyk

It is possible the mechanic did not use the proper torquing procedure needed when re-installing the pinion nut, with a used crush sleeve and gears.

The procedure requires that the torque needed to rotate the pinion/axle be measured and recorded before disassembly. Then on assembly the pinion nut is slowly tightened in steps, stopping to compare the torque needed to turn the pinion/axle, until that torque matches that recorded "prior to disassembly".

If this was not done it is quite possible that the gears would become noisy in a short time...

stevednmc

^^^This. You may or may not be surprised at how many "trusted" mechanics just tighten it (the pinion nut) down with an impact and call it good.

cliffyk

Steve,

As I suspect you know it not surprise me in the least--those are all the faithful and "experienced" followers of the German philosopher/mechanic Guttentite, famed for his "We don't need no stinkin' torque wrenches!" sermon delivered from atop a mountain of junk cars...

Finallyverted

I thank you all for your responses, now I am stuck with this dilemma, my car is going to be a cruiser but I also do not want it to be a slouch as well, so.. With this issue having to teardown this I might as well do some aftermarket parts thinking 3.73 gears or 4.10 gears and is the stock rear end 8.8? Should I be buying anything else to make this rebuild go smoother and help my car?

stevednmc

Ha! I am familiar. Most peoples stuff I need to fix have been injured by this philosophy.

Stock GT rear is an 8.8. 3.73 or 4.10's, your choice really. Cliffy has 3.73's, I have 4.10's. I love my 4.10's, and Ill love them even more when I can actually get any traction...My car is also not a daily driver. Alot of people who install 3.73's wish the went with 4.10's, but it depends on alot of factors, usage, exhaust, future mods etc.
If you do a gear swap, or need to tear down the Diff anyway, you should get bearing and seal kit, AM sells them, so do Jegs, Summit Brenspeed Etc..,Axle seals and bearings, and Carbon fiber clutch kit for your limited slip. (optional)

I did all this plus a ford racing diff cover as well. I am happy as could be.

Dont forget the oil! I used Mobil1 synthetic gear oil.

Convex

It's interesting reading the comments as i just had 4:10 installed and the guy told me to bring it back in afew days as they would tighten the pinon nut another 3 thousand after some break -in .. i can already hear the rearend howling alittle at 55 to 65 mph as it has about 150 mile on it since but i havn't took it back yet.

cliffyk

I have never heard of, read of or performed any re-tightening of the pinion nut after setting the initial preload. Ford makes no mention of a need to reset the preload in the shop manuals. There are two specs, one for reusing the bearings and crush sleeve (8 to 14 lb-in) and another if replacing it all (16 to 29 lb-in). The latter is intended to accommodate any "wearing in" of the new bearings, etc.

'Twas me I'd bring it back now. Undue noise from the final drive gears means they are not meshing properly, which means they are "wearing in" improperly...

Convex

Thank you Cliff for the fast reply as it was a new piņion bearing and sleeve, what can be done to fix it? Take it to the ford dealership? New piņion bearing and sleeve again?

cliffyk

Bring it back to "the guy" first, he may just have a different way of doing things (despite my advanced years I have yet to "see it all").

Also, has the noise you describe gotten louder/nastier sounding--or just something you have come to notice since the install? I ask because with 4.10 gears, for any given speed in any gear, the drive shaft will be spinning 25% faster than with the stock 3.27 gears. In 5th gear at 60 mph this means that instead of spinning 2650 rpm it will be turning 3320 rpm. With the stock gears if the driveshaft were turning 3320 rpm you would be traveling at 80+ mph.

This faster driveshaft speed, which can be quite noticeable, may be what you are hearing. Many have found that after 4.10 installs the driveshaft NVH was be more than they cared to deal with and installed aluminum shafts, or had the steel shaft rebuilt/re-balanced.

The same relationship (driveshaft turns faster) of course happens with 3.55s or 3.73s, however 4.10 gears seem to be the point at which it becomes most noticeable; particularly on higher mileage cars where U-joints can be a bit more worn and transmission and motor mounts a bit more stiff than when new...