Tech thoughts

[SavageSun4x4]

Atlas 5.0 or R&P. It will jump my lower gear TC ratio a good amount [from 4:1 to 5:1].

The other option is to re gear the axles. Doing that will impact all driving and provide a lower crawl ratio. That said, my concern then becomes RPM and wear. I rolled over 50k miles on the old rig this week and its still a DD. I don't plan on moving to a larger tire than the 37's I currently run, unless the Jeep becomes a trailer queen. Not likely unless I buy another Jeep or something down the road.

Current set up = overall crawl ratio: 78
Atlas 5.0 transfer case. 97
Regear axles w/5.13 R&P 82
Regear axles w/5.38 R&P 86

As you can see, to make a serious impact on crawl ratio its 5:38 over the 5.13's or the Atlas 5.0. However the 5.38 R&P will bring about some serious hiway rpm.

You thoughts on this?

[LKD TJ]

Don,
I have the Atlas and love it. I am going to 37's and have the 4.33:1 w/ 4.88 r&p. If it were me, I would go with the Atlas and call it good. It won't change anything on road and will give you the desired results off road. I went with the staight shift forks and had to modify the center console. The Atlas is a little bit louder (gear driven) but nothing I won't deal with. Big tires are louder than the TC. If you go to the 5.xx+ r&p it does make for some high revs and makes the hghway that much louder. If you want to take a look at the way I have the Atlas set up let me know. Just my .02.

[Crawldit]

Since your engine is supercharged I would try to play it safe with the RPM's especially with a DD and higher miles. Personally I'd go for the Atlas.

[Simon]

ATLAS...... for the sake of Dsrtjeeper!!!:D

[xFallen]

Atlas 5.0 or R&P. It will jump my lower gear TC ratio a good amount [from 4:1 to 5:1].

The other option is to re gear the axles. Doing that will impact all driving and provide a lower crawl ratio. That said, my concern then becomes RPM and wear. I rolled over 50k miles on the old rig this week and its still a DD. I don't plan on moving to a larger tire than the 37's I currently run, unless the Jeep becomes a trailer queen. Not likely unless I buy another Jeep or something down the road.

Current set up = overall crawl ratio: 78
Atlas 5.0 transfer case. 97
Regear axles w/5.13 R&P 82
Regear axles w/5.38 R&P 86

As you can see, to make a serious impact on crawl ratio its 5:38 over the 5.13's or the Atlas 5.0. However the 5.38 R&P will bring about some serious hiway rpm.

You thoughts on this?


StaK box.

http://jeephorizons.com/news/stak_071305.html
http://stak4x4.com/

It is even made in your home country motherland. ;)

I would love a lower crawl ratio of maybe 150:1 (4:1+4.88 = 77:1 now) but do miss the 2.73:1 of the old low. The StaK box is a nice alternative.

You could also put the remnants of a 231 in there and get a HUGE difference with the benefit of having 1:1, 2.73:1, 4:1 and 10.92:1. Mad Rooster is the ticket here if you have the room. This is partly why I went with the Tera ESS -- saves the 6" over a regular SYE that I need for one of these boxes...

http://www.pirate4x4.com/articles/productreviews/mad_rooster


Barry

[DsrtJeeper]

You know my biased opinion; Don. :D Unless you plan on running sand or mud; the Stak box or Mad Rooster's deal isn't worth it. The 5.0 will leave your options open down the road. If you go to those 40's some day; then you can regear. If you regear now; you may have to do it all over again with a larger tire. As you know; bigger tires equals Hydroboost and loss of that DD status that we much enjoy. ;)

Thanks Cole!!! :D

[Linda]

Advanced Adapters now has a 4 speed Atlas t-case with a 10:1 low range.

[xFallen]

Advanced Adapters now has a 4 speed Atlas t-case with a 10:1 low range.

I know it is in development but was not aware you could actually buy one. Last time I asked (a few months back now) the answer was no and they didn't have a firm date.

Sweet option. If one has the bucks, that would be the way to go. Same with StaK or Mad Rooster. The twin stick option is very nice to have though.


Barry

[mingoglia]

With 10:1 low range I could keep my 3.07 gears. :)

[4 Wheelers Supply]

I say leave it the way it is. You have a good set up now.:)

[1BLKJP]

I vote for the Atlas. Aren't you already geared to 4.88? But I like the idea of the 4 speed case they are coming out with. That should be a winner.

[rvisokey]

Does not having that low of gearing sacrafice a lot of strength in the R&P set? I always was told that gearsets got a little thin after 4.88 or so (obviously dependent upon axle model)

But I'm no expert.

[SavageSun4x4]

Does not having that low of gearing sacrafice a lot of strength in the R&P set? I always was told that gearsets got a little thin after 4.88 or so (obviously dependent upon axle model)

But I'm no expert.
Yes, your correct.

Rule of thumb: To keep your drive train balanced, keep each component [TC, Trans, Axles] in the same or close numbercialy. Meaning don't run an Atlas 5.0 with 3.07 axles and a 2.25 first gear in your tranny. So from that point I am in good shape with a Atlas 5.0, 4:1 frist gear and 4.88 axles.

[cactuscatcher]

I had the Rubi 4:1 and 5.38s on 40s (now 38s) and made the jump to the Atlas 6:1 and if I had it to do over again I would not have spent the money for the Atlas. It is only an opinion but given the costs for the changes and the result it was not money well spent in my experience. The only advantage so far has been the twin sticks and the crawl ratio is so low that I was using 2nd and 3rd gear/low range while testing the rig at TM. Given that there are several 241 conversion twin stick prototypes out I would not go the Atlas route again and may actually switch back to the 241.

[jeepsonly]

Wow 6:1. Man that's low :)

[SavageSun4x4]

I had the Rubi 4:1 and 5.38s on 40s (now 38s) and made the jump to the Atlas 6:1 and if I had it to do over again I would not have spent the money for the Atlas. It is only an opinion but given the costs for the changes and the result it was not money well spent in my experience. The only advantage so far has been the twin sticks and the crawl ratio is so low that I was using 2nd and 3rd gear/low range while testing the rig at TM. Given that there are several 241 conversion twin stick prototypes out I would not go the Atlas route again and may actually switch back to the 241.
6:1 is more than low, thats extreme low. I cannot see much use for the 6:1 except in mud/sand where you are using a high rpm crate engine with torque peaking around 4500 rpm + and peak HP around 5800 +.

One has to match the torque/hp curve of their engine to the expected use.

[SavageSun4x4]

Reviewing my current setup and what a Atlas 5.0 will do:

Current set up = overall crawl ratio: 78

Atlas 5.0 transfer case. 97

So keeping my 4:1 tranny low gear and my 4:88 axles, I move from a CR of 78 with my current 4:1 transfer case to a CR of 97 with the Atlas. That is an order of magnitude and will provide a major impact on my ability to crawl. Now bear in mind that the Atlas 5.0 affects the CR in all the gear sets, so I pick up more CR in 2nd -5th gear as well as first.

Rocks are my game and I avoid mud if at all possible and have no interest in sand.

Taking on the 'Rock Garden' in Martinez Canyon or Kane Creek in Moab [when its nearly dry] is quite a challenge and one almost can't go slow enough if you want to retain the filings in your teeth.

Will adding the Atlas 5.0 allow my rig to do something it can't do now? Not likely, but it may allow it to do it easier.

:confused: more thought needed...

[xFallen]

6:1 is more than low, thats extreme low. I cannot see much use for the 6:1 except in mud/sand where you are using a high rpm crate engine with torque peaking around 4500 rpm + and peak HP around 5800 +.

One has to match the torque/hp curve of their engine to the expected use.

I wouldn't want 6:1 in mud and sand. I am sure you know in mud and sand you want the tires spinning fast so you ride on top. This is how tires like the Bogger were intended to be operated. There are practical limits to how fast the internals of a low geared transfer case can spin and I think even at 4:1 one is approachig if not past that point. This is why the StaK box and others surface.

I am at an overal crawl ratio of 77:1 now and would prefer to be somewhere between 100 and 150:1. I think this boils down to it totally depends on your one personal preferences for driving style and trail.


Barry

[SavageSun4x4]

I wouldn't want 6:1 in mud and sand. I am sure you know in mud and sand you want the tires spinning fast so you ride on top. This is how tires like the Bogger were intended to be operated. There are practical limits to how fast the internals of a low geared transfer case can spin and I think even at 4:1 one is approachig if not past that point. This is why the StaK box and others surface.

I am at an overal crawl ratio of 77:1 now and would prefer to be somewhere between 100 and 150:1. I think this boils down to it totally depends on your one personal preferences for driving style and trail.


Barry
Thanks Barry. I'll tip my hat to you on mud/sand as I don't know squat, but your most likely correct.

[DsrtJeeper]

Don;
I know you have your own thoughts on this, but one of the best upgrades you could do right now would be to go to a LA lift. Keep in mind that I too started with a SA lift and nobody could tell me otherwise. It was until I hit the more difficult trails in Moab that I realized that the LA guys were smoking me in the undercuts, bumps, ledges and long bumpy rides back to town. It was night and day when I switched to a LA setup. I asked questions until I was blue in the face and nobody could tell me why I needed to spend the money to go LA. LA designs are nothing new and have been proven time and time again in offroad sports. It's not so much what you have accomplished with your current lift, but could it have been smoother, easier on the Jeep, given you more confidence, etc......
JMHO :)

[SavageSun4x4]

Don;
I know you have your own thoughts on this, but one of the best upgrades you could do right now would be to go to a LA lift. Keep in mind that I too started with a SA lift and nobody could tell me otherwise. It was until I hit the more difficult trails in Moab that I realized that the LA guys were smoking me in the undercuts, bumps, ledges and long bumpy rides back to town. It was night and day when I switched to a LA setup. I asked questions until I was blue in the face and nobody could tell me why I needed to spend the money to go LA. LA designs are nothing new and have been proven time and time again in offroad sports. It's not so much what you have accomplished with your current lift, but could it have been smoother, easier on the Jeep, given you more confidence, etc......
JMHO :)
Very little argument on that from me. In addition, I still have not engineered it in my mind. I like the Nth arms, but am not sold on a lift kit with more pieces than a one-man orchestra.

Now throw the current rage of ‘triangulated’ rears into the mix and it’s a complicated mixture. I am not completely sold on triangulation. The tangential force imposes a significant stress on arms, frame, and overall upper architecture. For triangulation to work properly then lateral movement must be nil or you’re back with the same results as a track bar. The track bar is not only a excellent design, but very rugged, reliable and long lasting, a trait that I am not sure that triangulation presents.

Besides, my ‘ole SA still has a few tricks left in its bag…

[TRobertsRN]

Is the Atlas 4 speed transfer with the 10 to 1 low available yet?

[SavageSun4x4]

Is the Atlas 4 speed transfer with the 10 to 1 low available yet?
I saw the one and only one, in Oct, I am not sure of the exact release date as I didn't ask and have no interest in it.

I am at a total loss as to what it would be used for.

[TRobertsRN]

It would be good for me in my 53 Willys Pickup. It has 4.10 axle gears. I had planned a SM420 with 7.01 granny to replace my T-90 transmission. I was keeping the original 18 transfer with low of 4:1 and 25% Saturn overdrive. This would have given me all the gears for highway speeds (overdrive, 33-37 inche tires), mud/sand, and rock crawling (100+:1). Now that I can no longer operate a clutch my plan is to intall an automatic transmission. As I have a 350 SBC that I plan to make a 383 I am leaning toward a TH400 (first gear is 2.48,I think can be modified to 2.75) or a TH700-R4.

So original planned crawl ratio would have been about 112:1, and have overdrive

With Atlas 10:1 crawl ratio and TH400 would be about 80:1,and no overdrive

With Atlas 10:1 crawl ratio and TH700-R4 would be about 120:1, plus overdrive. This may be my best choice but I am conserned that I have heard this transmission is not as strong as the TH400.