4L in soft deep sand

[AlgUSF]

This weekend I was pulling a trailer through deep Florida powder sand. It was a steel trailer with an ATV on it and it was quite the pull with my stock ATs. I have the 6 MT and saw 3-4K rpm for a couple hundred yards or so. The 4L "speed limit" is 25MPH... Is that due to the engine speed and covering different gearing and transfer cases? I kept it in 4L pulling that trailer and hit 3rd gear a few times. Is the 25MPH "speed limit" due to overspeeding the engine or is there another reason for that limit? I may have touched 5K momentarily to get enough momentum to get into 2nd and bring the revs down.

I'm just looking for improvements on technique. I typically rip through this stuff in 4H not pulling a trailer and was surprised how hard I had to work to get forward momentum with a trailer combination.

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[Beachcomber72]

In sugar/powder sand I run 4h with traction control completely off and I’m always aired down to 12psi on BFG 35’s. When pulling someone out in same sand conditions I always use multiple bubba ropes to gain as much distance to harder packed stuff I can from the other vehicle, also make sure they keep in same path as you and keep their front tires pointed straight forward at all time or if they turn the front tires you’ll now be dragging dead weight. I would have also made them offload the ATV for less weight being recovered.

 

[Beachcomber72]

To “completely” disable all traction control press and hold the traction control button till it dings and on your instrument cluster it will show “Electronic Stability Control Deactivated” and will auto turn back on in 2h.

 

[bjm00se]

I've been known to hit fifth gear, and maybe sixth, briefly, in 4l.

Naturally, if you're going to be running those speeds consistently, it makes sense to stop and switch back to 4h.

 

[AlgUSF]

In sugar/powder sand I run 4h with traction control completely off and I’m always aired down to 12psi on BFG 35’s.

I totally should have aired down a bunch before we left camp but I didn't bring my 12V compressor with me anyway. Last time I aired down out there it took me a good 15 minutes at the gate to air back up. Christmas list, better air compressor.

I now feel pretty dumb for not remembering to air down and bring the stuff to air back up.

 

[Old Jeeper]

This weekend I was pulling a trailer through deep Florida powder sand. It was a steel trailer with an ATV on it and it was quite the pull with my stock ATs. I have the 6 MT and saw 3-4K rpm for a couple hundred yards or so. The 4L "speed limit" is 25MPH... Is that due to the engine speed and covering different gearing and transfer cases? I kept it in 4L pulling that trailer and hit 3rd gear a few times. Is the 25MPH "speed limit" due to overspeeding the engine or is there another reason for that limit? I may have touched 5K momentarily to get enough momentum to get into 2nd and bring the revs down.

I'm just looking for improvements on technique. I typically rip through this stuff in 4H not pulling a trailer and was surprised how hard I had to work to get forward momentum with a trailer combination.

4 Lo is high rpm in the driveline and its internals. The internals get to spinning fast and furious and it puts a lot of stress on the transfer case. I know from time to time some cracks open a TC, but rarely. At 25 mph you engine is also spinning some rpms and you are prob getting close to over revving even tho the 3.6 is a high rpm engine to begin with.

Still not sure why they went with the 3.6 for the Jeep, I would have kept the 4.0 inline 6. All it would have taken to moderize that engine was a set of pistons that moved the CR up to about 9.5:1. The compression was so low on that engine you burn piss in it for surel. Then add in a cam with some more lift and bring the HP to about 325.

 

[Powelligator]

Still not sure why they went with the 3.6 for the Jeep, I would have kept the 4.0 inline 6. All it would have taken to moderize that engine was a set of pistons that moved the CR up to about 9.5:1. The compression was so low on that engine you burn piss in it for surel. Then add in a cam with some more lift and bring the HP to about 325.

Two words: Federal Emissions. Had nothing to do with gas mileage or CAFE, in 2005 and later the federal emissions requirements were updated slightly and the 4.0L was just too old a design to meet that. That's why the throttle body and fuel pump are different in '05's and '06's only.

 

[Old Jeeper]

Two words: Federal Emissions. Had nothing to do with gas mileage or CAFE, in 2005 and later the federal emissions requirements were updated slightly and the 4.0L was just too old a design to meet that. That's why the throttle body and fuel pump are different in '05's and '06's only.

The fix is cam and pistons...You make a Hi-performance engine rather than an old beater dating back to who knows when. Today we have engines cranking out 1000 HP that MEET emissions.

 

[KevinC11]

Anytime I am in Florida sugar sand and 4L, I am also aired down.

The transfer case in 4L cannot handle the high RPM's for extended periods. That is not what 4L was designed for. Designed for low speed crawling.

KevinC

 

[Powelligator]

The fix is cam and pistons...You make a Hi-performance engine rather than an old beater dating back to who knows when. Today we have engines cranking out 1000 HP that MEET emissions.

Cam, pistons, connecting rods, a little head work... I've built a lot of inline 6 strokers, I know it could have been done, but by 2005 the 4.0L was only in one remaining platform and for Daimler Chrysler (at the time) the future was in a V-6 that could be dropped into everything from a minivan to a Dodge Ram. It just wasn't worth the effort to change anything on an engine that wasn't going to physically fit in any of the engine bays in all the upcoming platforms. Kenosha needed the additional capacity for more of those early craptastic 3.5L V-6's.

 

[Old Jeeper]

Cam, pistons, connecting rods, a little head work... I've built a lot of inline 6 strokers, I know it could have been done, but by 2005 the 4.0L was only in one remaining platform and for Daimler Chrysler (at the time) the future was in a V-6 that could be dropped into everything from a minivan to a Dodge Ram. It just wasn't worth the effort to change anything on an engine that wasn't going to physically fit in any of the engine bays in all the upcoming platforms. Kenosha needed the additional capacity for more of those early craptastic 3.5L V-6's.

I do not doubt you at all and in fact agree. Looking out the eyes of a HARD CORE ROCK crawler (ME) that inline 6 was a dream of an engine. I did add a SC to mine but that was in keeping my views on driving to wheel and driving back vs trailering. My observation on trailering is they BREAK on the trail and it's the only way to get that chunk of metal back home. I have led a LOT of runs all over over my years and trailered rigs break that is a FACT.

If it was not for my SC I would had to drive around 50 mph, the SC was for highway use.
My dream was to take a Chevy crate motor, 383 stroker used in the HD truck line, TONS of torque down low. Never got around to it, tween wheeling and my shop I full time.

 

[Zandcwhite]

The planetaries themselves are the only thing "spinning fast" in 4LO. 8th gear in a stock Rubicon in 4LO gives you a drive ratio and therefore the same drivetrain speeds at a given speed of 10-1. 1st gear in 4 HI is nearly double that. 4LO 8th is closer to 3rd gear in 4HI. If you need the torque but also some wheel speed to get through a deep spot, there's no need to worry about shifting back to 4HI in my experience. Now if you're cruising long distance at 30+mph, why are you in 4LO anyway?

 

[6.2Blazer]

The planetaries themselves are the only thing "spinning fast" in 4LO. 8th gear in a stock Rubicon in 4LO gives you a drive ratio and therefore the same drivetrain speeds at a given speed of 10-1. 1st gear in 4 HI is nearly double that. 4LO 8th is closer to 3rd gear in 4HI. If you need the torque but also some wheel speed to get through a deep spot, there's no need to worry about shifting back to 4HI in my experience. Now if you're cruising long distance at 30+mph, why are you in 4LO anyway?

Pretty much agree with this. You are not going to hurt anything running in 4 LO, but just as said above if you can consistently cruise at 30+mph why do you need to be in 4 LO? If you bumped up over 25 mph for short periods of times, such as between really soft spots, but then had to slow down I wouldn't worry about it.
Not quote this post, but rather making a statement in regards to several other posts. You really aren't spinning anything faster when in 4 LO. You are spinning additional parts, which are the planetaries used for the reduction, but they are not spinning faster. What I mean is if you are in 2nd gear with the engine at 3,000 RPM the input speed into the transfer case is the same whether you are in 2wd, 4 HI, or 4 LO. Everything downstream of the transfer case planetaries is actually spinning slower for the same engine RPM and gear selection.

 

[Apexcars]

So, my question is...trying to pull a trailer through deep sugar sand, are you better off running 4Lo with lower wheel speed or 4Hi and keeping the wheel speed up. I don't live near deep sand but I have on occasion needed to cross part of a recently plowed field. Never with a trailer on though.

 

[Powelligator]

Holy double subject threads, Batman!

I come to these inline six's with a different philosophy, I like them simple. They're nothing more than tractor engines, but with enough displacement and properly balancing everything I can easily drive over the 11K foot summits in Colorado at 70 MPH with an engine that looks completely stock and therefore makes it through an emissions inspection with no eyebrows raised. And on the trail, having more than 300 foot pounds right off idle is as good as it gets.

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