I have the opportunity to buy a set of 3.73's with about 5000 miles on them. Is this a good idea, or should I spend the extra $50 and buy them brand new?

 

i personally would buy brand new ones, just to make sure that nothing is wrong with them. (If you know that they are in mint condition then go for it) The slightest little chip in gears can screw up your whole rear end. Installation + Gears is a decent amount of money. But wouldnt you rather know that the gears going in are brand new and nothing is wrong with them? Me personally i was going to put 3:73s in my car (the gears were used) But i got a deal at a local shop near me for new gears (4:10's) that were on sale and i picked them up and me and my buddy installed them. I felt safer knowing my gears were brand new and not used by someone else. Unless your doing the installation yourself then put the used ones in, but if worst comes to worst you can always uninstall them and put in brand new gears. But paying once for gear installation with new gears is better then paying for installation twice and having to get new gears. Just my 2 cents.

 

if the case hardening is worn off, they will screw up your rear end, it is not worth saving $50 when you can loose $1000

 

Buy New...

 

Definatly spend the extra $50 and get new.

 

I'm with everyone else...give yourself some peace of mind and get'em new.

 

NEW ONE'S.........
Heat treatment is probably off the used ones and they won't last........

 

I bought a used set of 3.73's for 50 bucks. They are FMS gears w/ nothing wrong w/ them. Installed and are quiet. I took the 3.55's that were in my car for 12 years and put them in my wifes car. Quiet as a mouse. There is nothing wrong w/ used gears as long as they are in tact!!!

 

I have to agree that I would probably buy new but you should be able to look at a used set and tell after 5000 miles if they were installed correctly in the previous car. Look at the surface wear pattern on the face of the teeth. If is is uniform front to back and top to bottom it is probably a good indication that they are ok. Unless the guy ran the rearend without oil I also doubt that they ever got hot enough to hurt the heat treating of the gears. You do need to make sure the gears have no nicks or dings in them. Of course looking at the gears won't tell you if they will be quiet when they are reinstalled in your car.

If you really want or need to save the $50, tell the guy you will take them but you want to have your installer look at them first. If the installer says they are ok then you should be good to go.

Good luck.