I’m new here - could be great…

[Zachanadandy]

One thing you didn't mention is getting in to overdrive gears is a reason people regear.

Crusing along in 7th gear on a flat highway doesn't sit well with everyone.

Sure there is confirmation bias with some mods, but you can't dismiss all accounts because of this.

7th is still overdrive and even on 37s I regularly see 8th. I don't know how people drive uphill or into a headwind everywhere they go to never see 8th even on 4.10s and 37s? And it's not like my JT is an anomaly. The wife's JLUR on 39s sees 8th too with its 4.56 gears. If you regularly tow a heavy trailer it might be worth the money, but even there my JT had no problems towing an 8200lb trailer 600 miles with plenty of hills. $3k to be in 5th instead of 4th climbing a steep grade? 8th instead of 7th out of some weird obsession with a number next to the D on the dash? Having run over a half dozen gear and tire combos in Jeeps with this 8 speed by far the wrost was overgeared to 5.38s and 38s. Sure it was in 8th all the time, at any aired over 40mph. Definitely looking for 9th gear at freeway speeds. The best combo was 4.56s and 37s for my use. Even the stock xr with 315s felt overgeared on the freeway. If regearing was free I'd probably go 4.56s in the JT and 4.88s in the JLUR, but I'm not dropping $6k to change the heat ratio by 1 step in each Jeep. From experience it won't gain much in mpg, acceleration, or crawling. Who cares if its in 8th 15% more of the time on the freeway?

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[Wheelin98TJ]

7th is still overdrive and even on 37s I regularly see 8th. I don't know how people drive uphill or into a headwind everywhere they go to never see 8th even on 4.10s and 37s? And it's not like my JT is an anomaly. The wife's JLUR on 39s sees 8th too with its 4.56 gears. If you regularly tow a heavy trailer it might be worth the money, but even there my JT had no problems towing an 8200lb trailer 600 miles with plenty of hills. $3k to be in 5th instead of 4th climbing a steep grade? 8th instead of 7th out of some weird obsession with a number next to the D on the dash? Having run over a half dozen gear and tire combos in Jeeps with this 8 speed by far the wrost was overgeared to 5.38s and 38s. Sure it was in 8th all the time, at any aired over 40mph. Definitely looking for 9th gear at freeway speeds. The best combo was 4.56s and 37s for my use. Even the stock xr with 315s felt overgeared on the freeway. If regearing was free I'd probably go 4.56s in the JT and 4.88s in the JLUR, but I'm not dropping $6k to change the heat ratio by 1 step in each Jeep. From experience it won't gain much in mpg, acceleration, or crawling. Who cares if its in 8th 15% more of the time on the freeway?

It's not an obsession with the number next to the D on the dash. You can just turn that off.

It's about preferences that match user needs and desires. I don't drive my Jeep 85 MPH. If I did, I probably wouldn't run 5.38 gears.

 

[Supazuk]

I guess "fast enough" is relative. 55mph on the highway is a far cry from 80+ on the freeway. Sure my old XJ was ok driving locally with 35x14.50 pit bull tires and 4.88s but it definitely wasn't getting driven to Moab 1,100 miles away. Even up to the rubicon 4 hours away it was mediocre going up I5 and could barely maintain speed on the way up the sierras. And even then the crawl ratio was an unimpressive 37.8-1. And it was a later model with overdrive. Get a YJ or early TJ with no overdrive and it's even worse. The JLUR in the driveway came with an 85.7-1 crawl ratio and even on 39s will cruise at 100mph if I want to. We are on Jeeps 15 and 16 in the driveway right now and I miss nothing about the zjs, yj, tj, jk, xjs, or wagoneers we built and wheeled over the years. The v8 wj was the only one that felt like it had enough power on road. The leather seats in that thing were amazing too. Still wouldn't go back by any means. The JLUR and the JT mojave are better on every way. Ever take a TJ through washboards at freeway speeds? Hard pass. The JT is more comfortable there at 70+ than the tj was on the freeway at that speed.

I guess you need more diff gears and doubler

I get your point, but your numbers are a little off.

With a 3 speed auto, 4.56, and 35" tires, 3k RPM at about 65 MPH. Crawl ratio of 34:1.

those are amateur crawl numbers, My zuk in it last street setup full sami body with tracker 1.6 EFI 5 speed dual t-case (kicker III 5.16 case front, 2:1 doubler ) w/ 4.30 yotas on 36's final crawl about 170:1 and could still cruise at 75 from NH to FL and back

 

[Wheelin98TJ]

I guess it is relitiv

those are amateur crawl numbers, My zuk in it last street setup full sami body with tracker 1.6 EFI 5 speed dual t-case (kicker III 5.16 case front, 2:1 doubler ) w/ 4.30 yotas on 34's final crawl about 170:1 and could still cruise at 75 from NH to FL and back

You could do the same with a TJ if you wanted to.

 

[Lunentucker]

Is this still available?
Anyone got pics of one installed?

 

[ShadowsPapa]

7th is still overdrive and even on 37s I regularly see 8th. I don't know how people drive uphill or into a headwind everywhere they go to never see 8th even on 4.10s and 37s? And it's not like my JT is an anomaly. The wife's JLUR on 39s sees 8th too with its 4.56 gears. If you regularly tow a heavy trailer it might be worth the money, but even there my JT had no problems towing an 8200lb trailer 600 miles with plenty of hills. $3k to be in 5th instead of 4th climbing a steep grade? 8th instead of 7th out of some weird obsession with a number next to the D on the dash? Having run over a half dozen gear and tire combos in Jeeps with this 8 speed by far the wrost was overgeared to 5.38s and 38s. Sure it was in 8th all the time, at any aired over 40mph. Definitely looking for 9th gear at freeway speeds. The best combo was 4.56s and 37s for my use. Even the stock xr with 315s felt overgeared on the freeway. If regearing was free I'd probably go 4.56s in the JT and 4.88s in the JLUR, but I'm not dropping $6k to change the heat ratio by 1 step in each Jeep. From experience it won't gain much in mpg, acceleration, or crawling. Who cares if its in 8th 15% more of the time on the freeway?

I don't see 8th very much around here - honestly. It does happen more with the Mojave than it did with either of my Overlands where I could drive all the way from west to east mixmaster on the north side of Des Moines and stay in 6th or 7th at 70 mph.
It's almost always windy, and it's quite hilly unless you get to where the glaciers hit eons ago. Even the semis are constantly shifting in our area.
I really don't care much any more - it is what it is. If I'm in 7th, I know I'm above 1:1 at least and if I hit a flat on a rare calm day and see 8th, I guess that's what it's intended for.
Basically in a nutshell - bone stock around here - 8th is pretty amazing.

As far as a 4.0 being happy at 3,000 RPM- mine sees that a lot. Shifting into 5th is something you don't do at 55 or below, so I'm running upper 2,000s a lot, closer to 3K and I may decide to hit 5th at 60-65 mph and get it back down 2,000 or so.

The owners manual (written with the 258 in mind) said do not shift into 5th at speeds below 55 mph. The speedometer is red at above 55 mph. There was a national speed limit of 55 - so if you aren't supposed to go over 55, and you aren't supposed to shift into 5th below 55............ hmmmmm.

 

[Zachanadandy]

I guess you need more diff gears and doubler

those are amateur crawl numbers, My zuk in it last street setup full sami body with tracker 1.6 EFI 5 speed dual t-case (kicker III 5.16 case front, 2:1 doubler ) w/ 4.30 yotas on 34's final crawl about 170:1 and could still cruise at 75 from NH to FL and back

If you had more than 40ftlbs of torque you wouldn't need so much gear reduction. It's always the Toyota and samurai guys that want to flex about their 2 transmissions and 4 speed transfer cases...its not the flex you think it is. 6k rpms at 1 mph has never impressed anyone with more than 4 cylinders. I could power my Jeep with a dewalt drill with enough gear reduction... but why? Gearing doesn't make up for the lack of power, which is why even with the 170:1 you still had to do any engine swap. That's why nobody is making doubler kits for JLs and JTs even though they were super popular for even the 4.0L powered Jeeps. Turns out 100 extra hp means I don't need 100x more gear reduction. The JT will get a supercharger long before a doubler for that same reason. It has plenty of gearing with the power is already got.

 

[Zachanadandy]

I don't see 8th very much around here - honestly. It does happen more with the Mojave than it did with either of my Overlands where I could drive all the way from west to east mixmaster on the north side of Des Moines and stay in 6th or 7th at 70 mph.
It's almost always windy, and it's quite hilly unless you get to where the glaciers hit eons ago. Even the semis are constantly shifting in our area.
I really don't care much any more - it is what it is. If I'm in 7th, I know I'm above 1:1 at least and if I hit a flat on a rare calm day and see 8th, I guess that's what it's intended for.
Basically in a nutshell - bone stock around here - 8th is pretty amazing.

As far as a 4.0 being happy at 3,000 RPM- mine sees that a lot. Shifting into 5th is something you don't do at 55 or below, so I'm running upper 2,000s a lot, closer to 3K and I may decide to hit 5th at 60-65 mph and get it back down 2,000 or so.

The owners manual (written with the 258 in mind) said do not shift into 5th at speeds below 55 mph. The speedometer is red at above 55 mph. There was a national speed limit of 55 - so if you aren't supposed to go over 55, and you aren't supposed to shift into 5th below 55............ hmmmmm.

Almost like rules were made to be broken? Why are our jeeps limited at 100mph when the highest speed limit in the nation is 85? Why can I buy a model s plaid and drive it on the street when its so ridiculously over powered you'd need a cage, helmet, and parachute to run it at an NHRA track? An 8 second street car that traps 150mph and does 0-60 in 1.9s is clearly capable of breaking a whole bunch of laws. Obviously I'm not saying the straight six is red lining at 3k or 3500+ cruising freeway speeds but it certainly isn't great for it for hours at a time and I can only imagine how bad the fuel economy world be.

 

[ShadowsPapa]

Almost like rules were made to be broken? Why are our jeeps limited at 100mph when the highest speed limit in the nation is 85? Why can I buy a model s plaid and drive it on the street when its so ridiculously over powered you'd need a cage, helmet, and parachute to run it at an NHRA track? An 8 second street car that traps 150mph and does 0-60 in 1.9s is clearly capable of breaking a whole bunch of laws. Obviously I'm not saying the straight six is red lining at 3k or 3500+ cruising freeway speeds but it certainly isn't great for it for hours at a time and I can only imagine how bad the fuel economy world be.

It's a long stroke, lower RPM engine not made for the higher RPM for sure.
I have achieved mid to upper 20s (mpg) with the 4.0 in my SX4 but I've quit tracking it - really don't care these days. I know what it can do if the RPM is kept down and I use the higher gears where I can. My goal was to build a car that would get over 20 easily, be fun to drive (the short wheelbase, the T5 transmission), be reliable, easy to start. I did it.

 

[Supazuk]

If you had more than 40ftlbs of torque you wouldn't need so much gear reduction. It's always the Toyota and samurai guys that want to flex about their 2 transmissions and 4 speed transfer cases...its not the flex you think it is. 6k rpms at 1 mph has never impressed anyone with more than 4 cylinders. I could power my Jeep with a dewalt drill with enough gear reduction... but why? Gearing doesn't make up for the lack of power, which is why even with the 170:1 you still had to do any engine swap. That's why nobody is making doubler kits for JLs and JTs even though they were super popular for even the 4.0L powered Jeeps. Turns out 100 extra hp means I don't need 100x more gear reduction. The JT will get a supercharger long before a doubler for that same reason. It has plenty of gearing with the power is already got.

gear reduction is not about power more for control speed is the enemy of rock crawling

 

[Supazuk]

That's why nobody is making doubler kits for JLs and JTs even though they were super popular for even the 4.0L powered Jeeps.

atlas is making 2 speeds adapters for for JL /JT... and name one LS buggy in KOH not running a 2 speed ...

 

[Zachanadandy]

gear reduction is not about power more for control speed is the enemy of rock crawling

That's only true to a point. You don't want to be at 20mph in 1st gear at peak torque but you also don't want to be a 20ft per hour either unless you just have no torque to move the vehicle. With the 4.7 1st gear in the 8 speed and the power out of even the 3.6L you just don't need 2 transfer cases which is why that market doesn't exist. It's no harder to put a doubler in a JL than a TJ, but you just don't need it. I've never once been out in the JLUR on 39s with its stock 85:1 and thought I need more gear reduction. It will creep along just fine in 1st gear, to the point that I don't even use it aside from the biggest obstacles. For the JT it's even less necessary as I rarely even use 4lo in the desert. A tracker motor with 85hp and 95ftlbs needs all the torque multiplication it can get. Double the power output and you only need half the gearing. Half of 170 is...85. And I'll still take the extra 200hp on road any way you gear the geo.

 

[Zachanadandy]

atlas is making 2 speeds adapters for for JL /JT... and name one LS buggy in KOH not running a 2 speed ...

A standard transfer case is a 2 speed. 1 to 1 and whatever low range. I haven't seen a single ultra 4 car running a 3 or 4 speed tcase. Most run an atlas 2 with a relatively high low range in fact. Either 2:1 or 3:1. Nobody is racing at 20ft/hr. You aren't climbing back door in compound low, you'll never make it. Bomber fab sells/markets their ultra4 specific atlas 2s....2:1 low range 2 speeds. https://bomberfab.com/collections/transfer-cases/ultra4

 

[Supazuk]

That's only true to a point. You don't want to be at 20mph in 1st gear at peak torque but you also don't want to be a 20ft per hour either unless you just have no torque to move the vehicle. With the 4.7 1st gear in the 8 speed and the power out of even the 3.6L you just don't need 2 transfer cases which is why that market doesn't exist. It's no harder to put a doubler in a JL than a TJ, but you just don't need it. I've never once been out in the JLUR on 39s with its stock 85:1 and thought I need more gear reduction. It will creep along just fine in 1st gear, to the point that I don't even use it aside from the biggest obstacles. For the JT it's even less necessary as I rarely even use 4lo in the desert. A tracker motor with 85hp and 95ftlbs needs all the torque multiplication it can get. Double the power output and you only need half the gearing. Half of 170 is...85. And I'll still take the extra 200hp on road any way you gear the geo.

You would have to know that pic and the days of my old zuk are from 2007 power to weight 97 hp in a 2000 lb rig that ultimately became a buggy on 39's

However I was kinda half agreeing with you on modern drivetrains.. the JT however is just as under powered @ 285 hp weighing 5100lbs. power to weight is not far off of each
and the zuk was geared better stock
MY JT has 4.10 sport tcase and 35's it definitely needs more gear and power to move up to the 40's i would like

 

[Zachanadandy]

atlas is making 2 speeds adapters for for JL /JT... and name one LS buggy in KOH not running a 2 speed ...

https://www.jlwranglerforums.com/forum/threads/atlas-4-speed-in-jlur.106799/
Even calling advance adapters they only offer the 2 speed for the JL and JT. Could you make a 4 speed work? Maybe but there's no need.

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