New rearend question

[04mustang70]

Im getting a new center section for my 9 inch.

What type of fluid should I use?

What type and how much "friction modifier" should be used?

What size speedo gear should I use in a FMX tranny with 3.70 Gears? My stock gear had 19 teeth.

Is there any kind of break in when running new gears?

This is my first time with new gears and just want to make sure I don't screw anything up.

Thanks, you guys help us guys out ALOT

 

[jst6]

well a couple of q's need to be asked first...

are you using a limited slip or a locker? makes a big difference.

The speedo gear will be selected when you go and get the speedo calibrated at a local shop that does that. They will runn your car on a dyno specifically for speed calibration vs. RPM and give you a sheet of your speed differences and recomend a gear for the trans.

If the gears are set up properly there should be no break-in period per say, but I would always give new rotating parts at least 500+ miles on them before pounding them on the 1/4 mile.

It will be tough to screw it up if you have a good mechanic setup the center section properly. and really they will have all these answers as well. if you are ordering from one of the big three (curree, moser, or strange) just call up their support line and they will be more than happy to help. heck curree led me thru some stock rear end issues and i never even bought any of thier product. now that's customer service. you think i'm going to buy from them in the future? heck ya!

 

[D.Hearne]

Friction modifier? Local Ford dealer has that in stock. Speedo gear ? 21 tooth, more'n likely

 

[04mustang70]

Im using a Trac Loc. Would this be considered a locker? Do I need a friction modifier with this? If so how much do you use?

 

[zigmont]

Gear calculator

See if this link helps


http://www.sccoa.com/faq/speedgr.html

 

[D.Hearne]

Traction loc needs the friction modifier. T/L is Ford's std clutch type posi unit. It's what their friction modifier's made for.