I am planning on getting a set of 3.73’s for my auto. Aside from the FRPP gears, what else is recommended and where can I get it?


Tim

 

The gears will have a new crush sleeve and pinion nut. You can press off the diff bearings and reuse them if they are low mileage. However, bearings are cheap and as long as he is in there I would probably change them. If you buy the master install kit you will get pinion bearings and diff bearings and usually a diff cover seal. I can't remember if the master install kit comes with shims or not. You will also need 2 quarts of gear oil and 1 pint of friction modifer.

Can't think of anything else. I am sure someone will step in and mention if I have forgotten something. I just installed a Detroit Truetrac, Strange 31 spline axles, FRPP aluminum drive shaft, and rear girdle last weekend.

 

The installation kit is definetly reccommended. It's like 40 dollars, but it's great for the mechanic, and you only want to have to do gears once. As for the gear oil... I would definetly reccommend using Royal Purple 75w140 which is GL 4 and 5, and also has the limited slip additive.

You'll LOVE the gears with the auto. Feel free to give me a shout if you have absolutely any questions at all. We have all of these items in stock for same-day shipping! THANKS!!

CR
Tillman Speed
610-497-3711

 

The A kit is recommended if your bearings are ok.
http://www.gefracing.com/Merchant2/m...ry_Code=46REAR

The B kit is recommended if you need bearings as well as what's in the A kit.
http://www.gefracing.com/Merchant2/m...ry_Code=46REAR

I prefer Torco SGO 75W140 with the FRPP friction modifier

 

I got the FRPP gears which came with shims, crush sleeve, pinion nut in addition to the ring and pinion. At minimum you will need to replace the pinion bearing as you will NOT get the old one off without destroying it. If the vehicle is high mileage you may want to replace the side bearings. You will need approx. 2.25 liters (quarts) of oil. Synthetic is best. I used Mobil 1 75w90.
You will also need some gear marking compound to check the pattern and a dial indicator with a magnetic base to check for runout and backlash.

 

Thank you everyone for the responses! The car has 7500 miles, but I may do all of the bearings just to be on the safe side. I really only want to have to do this once!

Tim

 

can you just take it to the dealer to have the speedo calibrated after the gear change??

 

If you have a tuner such as an SCT Xcal or a Diablosport Predator you can change the speedo calibration yourself. If not the dealer can do it. I am not sure the cost but they can do it.

 

I have an XCAL2, so I will be able to re-load my tune and choose the new gear ratio from the custom options menu. I’m not sure what you do if you lack an XCAL.

Tim

 

Additionally, make sure your tuner left the end user adjustability for Axle Ratio.

CR
Tillman Speed
610-497-3711

 

I've said it before, but I'll say it again. I prefer to let the gear installer provide 100% of the parts and labor. That way if anything goes wrong, it's on them to get it right. They can't come back and blame it on parts I provided to them. It may cost 20 or 30 bucks more that way, but better safe than sorry.



The guys who just did mine (San Diego Gear and Axle) are top notch. They only do rear ends, and they cover the gamut from street cars, to drag cars, and off-road trucks. They absolutely will not use synthetic oil in the rear end. They don't believe that it adheres to the gears as well as conventional oil.

Check out Tech Tip #2 here on their website: http://sdgearaxle.com/_wsn/page4.html


.

 

That's good info Don. I never would have thought of it that way but it does make sense. In the climate where I live I can't use 140 wt due to the cold but in warmer climates it would be ok.

 

I know that this is an old thread but I am changing the 3.73's that are in my car for 4.10's and I need a little help with changing the speedo calibration. My car has a Procharger D1SC on it and is tuned with a Predator hand held. Anyone have something similar to this
know how to adjust the speedo? Thanks in advance.

Ryan

 

I have a Predator tuner, as well, and I edited the tunes myself. There is a menu in your tuner where you can change the gear ratio. You will also want to adjust the tire revolutions per mile after that to fine tune the speedometer based on tire height (the default setting from Predator is off a little). Once you've edited your tune, you can hit "install" to reflash your old tune with the new settings. Will take just 10 minutes of your time.