investinwaffles

Yeah, my plan is to assess the condition of them before install, and have a set ready if needed

$30 for Powerstop Z36 pads
and $60 for Centric Premium rotors, or $30 for cheap rotors (probably going cheap initially, I barely use my brakes with the manual trans)

Also, I am committed to the 8.8 I guess. Just won an auction for the diff cover I wanted for the rear. $65 vs $130 MSRP ($80 on ebay). Hopefully it fits the larger gears, but couldn't pass up the deal. Worst case it can go on one of my Mustangs
http://ebay.to/2oPgcbT

EDIT:
To be clear, that cover is going to be for the initial break-in and drive cross-country. I will upgrade the diff cover to something beefy but as-is, I have never hit the rear diff cover on anything (or the front for that matter)

investinwaffles

Front outer axle seals - worth it?
http://www.4wheelparts.com/Drivetrai...&t_pn=ALY11102

http://www.ebay.com/itm/Dana-30-Dana...RUpENJ&vxp=mtr

aka"dude"

Yeah, you can probably imagine the amount of gnarly stuff that builds up in those axle tubes.

5-Speed

I got 3.73s with 31s and find it almost too much for freeway travel (70mph is 2600 rpms). I have an ax15 as well. I honestly feel like I would be more then fine running 33s. And I get around 22mpg at 70.

investinwaffles

Anyone know how to calculate RPM/Gear/Speed?

I am shooting for about ~2800rpm at 75mph in 5th gear (33" tires) but all the calculators are giving me different #'s

I am pretty much flipping back/forth from 4.56 and 4.88 gears on an hourly basis

XJlimitedx99

AX-15 --> NP231 --> 4.56 --> 33s = 2751rpm at 75mph

according to http://www.grimmjeeper.com/gears.html

investinwaffles

Epic - I had not seen that calculator! That should be a sticky, does all the gear calculations for you!


Going with 4.88's, I think 2700 rpm @ 70 MPH is perfectly fine, right now I am in 4th all the time so I usually at 2800 RPM anyways (just in 4th)

In case anyone is wondering (5th gear #'s)

3.07;
60 mph @ 1480 rpm
70 mph @ 1730 rpm
85 mph @ 2100 rpm

4.56;
60mph @ 2200 rpm
70 mph @ 2550 rpm
85 mph @ 3100 rpm

4.88;
60 mph @ 2350 rpm
70 mph @ 2750 rpm
85 mph @ 3340 rpm

Apparently, my top speed in 5th with 3.07's is 211 mph, and would drop to 132 mph with 4.88's
If I had 900 more horsepower

Jeepin'_Aint_EZ

4.56's with 35's here. I'm happy with the way it drives. I preferred to have the extra strength of the 4.56 pinion versus the 4.88 pinion in the D30. They get tiny.

investinwaffles

IDK, I read up a bunch and tons of people beat on the D30 with 4.88 gears and a locker and say its just fine. Might talk to the installer (if you look at his page, its literally just Jeeps and Fords getting gear or axle swaps)

http://bit.ly/2okWO3Y

Really, my biggest concern is long-haul highway trips. I am really not that hardcore when it comes to wheeling any more - I usually take the easier bypass and watch my friends beat the crap out of their trucks

Mine is mostly a camping rig and daily driver, if I am break the pinion I am wheeling too hard anyways

LACK

Its not the size of the pinion, its how you use it.

00t444e

MPH X transmission gear ratio X axle gear ratio X 336 divided by tire size equals RPM.
So If you have and AW4 transmission it has a .75 overdrive ratio and with 4.56 gears, 33 inch tires going 75 mph your equation would look like this.

75X.75X4.56X336
33
Answer= 2,612 RPM
Keep in mind most tire sizes are smaller than listed and the only way to accurately get speed is with GPS.

investinwaffles

Got in touch with him today - $1800 including rebuild of both diff's

That is including the cost of new brakes in the rear (incl. parking brake hardware), new front axle u-joints, LSD rebuild, cleaning out he front axle tubes, etc. And including install, seems like a good deal to me

Skipping the outer axle seals for now, I want to make sure the inner ones aren't leaking and maybe after the break in period I will add those.

Fingers crossed - pretty nervous about the gears being set-up properly and not burning up, but in the last week alone he has done 3 or 4 swaps so I have faith that he can get it done the first time.

EDIT:
Still looking into this, but will the explorer parking brake cables work with the XJ?

Jeepin'_Aint_EZ

LMAO this will live on in my signature

LACK

Im so honored.

investinwaffles

Flopped back and am now thinking 4.56 after a long and hard thought about going up to 35s

Decided that I really need armor and lockers, more camping gear, etc before I can justify the move up. Plus I want to keep this thing as a highway hauler to get me to/from cool camping spots, or across the country and I feel like 33's is a good medium.

Hope I don't regret it, or flop back because I can't really make up my mind. 4.88 would be nice, but I don't expect to be towing long distances alot (maybe a small motorcycle trailer or something). I really don't want to deal with the engine screaming for thousands of miles at a time (3300 rpm is a fairly high cruise rpm), though 3100 is only a stones throw away.

Calculations seem a bit low from when I was on the highway earlier today - 70 mph is closer to 2K rpm in 5th IIRC, but next time I am on the highway I will take note to see for sure.

So if the calculations are low for my current ratio, than they will probably be a bit low for all ratios

Anyways, all the more reason to keep it a bit milder. If I decide to go full on trail rig, I will be sure to go up to 5.18's and a D44 front

The indecision is killing me...
Scheduled for next Wednesday so maybe I'll just flip a coin