I use 75/140. Its proven to me to be the best weight for stock diff after switching over for many miles now. Makes sense, the cold weight is still standard for proper flow rate/lubrication and the hot weight is thicker to help cushion and protect the diff under added stresses. I DD and road course the car with this fluid, so its proven for me.

 

I had recalled a puddy thread way back that said the weak point is the crush collar on the pinion gear. That 'crushes' and the gearset goes out of alignment slightly, and the force/leverage increases, flexing (and possibly breaking) the end caps, and at the very least tearing up the gears as the pinion and ring gear separate a little. This would happen regardless of whether you cryo treat.

Comptech does nothing with the crush collar. From what I hear, puddy builds a custom sleeve to replace the crush collar, making the above pretty much never happen.

 

Hi Benton,

my puffy mod stage 3 with 3.9 gears just shipped. Looks good so far.

This pic shows the assembly...PuddyMod solid steel sleeve is on the pinion Note the shot peen finished gears.


This pic shows balancing the carrier and the ring gear, balance is just at a thousands true round.


This pic shows the PuddyMod solid steel sleeve being set


This pic shows the turning torque on the pinion after the PuddyMod solid steel sleeve is custom fitted, it is set at 12 inch pounds.


This pic shows the backlash set at 2.4 to 3.0 thousands, it also shows the perfect gear to gear pattern.



This pic shows the finished rear build. Note the information on the LSD also note the shot peen finished gears.



THE REAR IS SHIPPED DRY WITH NO OIL INSIDE PLEASE ADD OIL BEFORE USE

Break in,

This rear will hold power very well but is not bulletproof! Be sure to rev match your shifts! When you launch the car preload the drive train, be smooth, and get some tire spin.

Use a good quality GL-5 Hypoid 75/140 gear oil in the rear. Use this oil in the rear for 500 miles then drain.

Use Amsoil, Mobil1, Valvoline, or Motul 75/140 gear oil every 12K miles.

When you receive the rear, fill it with oil Be sure not to over fill the rear, fill the rear until the oil starts to come back out of the fill hole. Replace the fill bolt once the oil slows to a light trickle

More Break in:

Drive the car like a civilized human for 300 miles, No launching, power shifts, or hard down shifts. After 300 miles the rear is fully broke in and “normal” driving can begin.

Thanks

Ben

 

So I been drive the car with the new puddy mod stage 3 diff and 3.9 final drive for about a week now and I love it. The diff is dead quiet and the 3.9 years do make each gear noticabable longer. Cruzing rpm on the freeway is about 400-500rpm lower. When my speedo reads 80mph I'm actually going about 86mph. This will definitely help with my traction problems as 1 to 3rd gear is much more usable now. As before 1st and 2nd gear were only burn out gears and were useless. 2nd gear is now somewhat usable and of course 1st gear is still useless. Over all I'm happy so far with this new diff.

 

^^^^
Puddymod FTW glad you're liking it

 

Thanks for the update! Good info! I'll probably go down this path someday soon.

Thanks

 

I have a 3.90 puddymod diff for my AP2. I kind of wished that I went 3.63. 3.90 would be good for AP1 In mo opinion.

 

Wow... Really? Hmmm

 

Wasn't much of a difference, but I'm still happy having a beefed up diff.

http://www.turnzero.com/technical_re...ear_calculator

 

Hmm...I'll need to consider that.

Thanks