cliffyk

+1, they should not make any noise--if they do they are improperly adjusted.

Also, normal operating temperature for the rear end is 150°F to 175°F, sometimes more at extended high speed or under heavy load--the threshold of pain for we humans is 140°F...

1fastang

OK, I wasnt sure on the hot housing, never really checked before this, so that isnt a concern, but the noise is. so, I'll take it back and see what the shop can do . thanks for the info.

1fastang

I talked to the shop and he said it could make noise up to 500 miles, I never heard this before. he said to put the nos on it and go for it, I did and 5900 in 4th gear at 111mph seems like its not a 3.90 more like a 4.10 or 4.30 which is what I wanted to avoid.
I wanted to be able to go to the track and have alittle room to improve hp . I just got a new set of mickey thompsons 275/40/17, so I might have to go to a taller tire, maybe,
what do you guys think??

cliffyk

111mph @ 5900rpm in 4th is as close to the calculated 112.1mph as one could expect from the stock tach and speedometer.

Here's a link to my "How fast can I go in each gear?" calculator.

You might also like to check out the Axle Ratio Calculator (there's a link on the upper right of the "How fast..." webpage; plugging in your 111mph, 5900rpm, and tire size it says 3.90:1...

WhiteFoxGT

If your are lookin for more mph just bump the rev limiter up to 6500. Still shift each gear and spray till 6 however 4th gear you can pick up a cpl mph on the big end

1fastang

I have not got a tuner yet, just using a GPS for mph . what do you think, is this motor gonna hold say 6300rpm's . I figure that will get me through the traps. I do have a window switch for the zex kit, I want to set it at 5900 so I dont run it while shifting, it has worked great without it , but figured better do it for the track, and I will shut it off for 1st gear..

1fastang

damn, shoulda done some research. I woulda went 3.73 if I would known that. it is quicker out of the hole w/out nos thats for sure. but I do go to the track 3-4 times a yr.
other than that it street racing that usually doesnt go all out.. gotta luv the cruises , daytime racin.....

1fastang

its been about 500 miles and the noise in the gear has become a loud grind. the shop agreed and called motive. motive said thats common in the 8.8's and would warranty the
part. the shop is going to replace it with a ford motorsport 3.73 gear and charge me the labor. I disagree with that , but am at their mercy.

cliffyk

Motive makes many FRPP gearsets, in fact the FRPP 3.73's I've been running for 70k miles were made by Motive..

The shop screwed up the install (the fact that they told you "it would get better" is evidence of this), if they are making you pay for labor anyway. then get the gearset Motive has offered and find another more competent shop to install them...

teej281

Youre going to wish that you were running a steeper gear my friend...