Upping to 4.88 gears; Re-Gear the 8.25 or swap in an 8.8??
#16
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Year: '98
Engine: 4.0 I6
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)
$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)
Last edited by investinwaffles; 04-08-2017 at 03:44 AM.
#17
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Year: '98
Engine: 4.0 I6
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
http://www.4wheelparts.com/Drivetrai...&t_pn=ALY11102
http://www.ebay.com/itm/Dana-30-Dana...RUpENJ&vxp=mtr
#19
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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.
#20
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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
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
Last edited by investinwaffles; 04-10-2017 at 01:10 AM.
#21
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Year: 1999
Model: Cherokee (XJ)
Engine: 4.0 L
AX-15 --> NP231 --> 4.56 --> 33s = 2751rpm at 75mph
according to http://www.grimmjeeper.com/gears.html
according to http://www.grimmjeeper.com/gears.html
#22
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Year: '98
Engine: 4.0 I6
AX-15 --> NP231 --> 4.56 --> 33s = 2751rpm at 75mph
according to http://www.grimmjeeper.com/gears.html
according to http://www.grimmjeeper.com/gears.html
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
#23
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Year: 1998
Model: Cherokee
Engine: 4.0L
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.
#24
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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
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
#26
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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.
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.
#27
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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?
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?
Last edited by investinwaffles; 04-11-2017 at 02:25 AM.
#30
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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
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