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Discussion Starter · #1 ·

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Discussion Starter · #2 ·
My current setup is
AX-15 = 3.83 1st gear
np231 = 2.72 lo
axles = 4.88
-----------
50.838

this is with a 6 cyl manual 4K# rig on 38" tires

This is not the ideal crawl ratio, I intend to go much lower - just a reference
 

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Discussion Starter · #3 ·
700R4 231 (auto)
3.06 2.72 4.88 = 40.62

700R4 4to1 (auto)
3.06 4 4.88 = 59.73 *

700R4 atlas (auto)
3.06 3.8 4.88 = 56.75 **

700R4 atlas (auto)
3.06 4.3 4.88 = 64.21 *

700R4 atlas (auto)
3.06 5.0 4.88 = 74.66
 

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O.K. Here is my opinion and just an opinion.
I got a Toy truggy, and at one time had a 4.7 marlin gear in the t-case. Worked great for puttin' around in the hills and what not, but if ya want to play with the big dog's ya gotta be able to spin those tires. I ended pulling out the 4.7 t-case and going back to the stock. I have a very "peppy" 22r in the truck and I have found that if your going verticle chances are your going to need a little momentum. I have seen plenty of rigs crawl right up alot of things, but the torque created by the 4.7 gears was just to low causeing the tires to spin on the slightest inclines. Now if ya got a auto tranny it is a whole different ball game, with an auto you can control the torque much better than with a clutch, not to mention that a torque converter acts like a 300:1 reduction, or at least that is what I was told. So I guess in general it depends on your driving style, where you want to go and how ya want to get there. I don't really think there is a perfect ratio, it is a personal opinon (like this post)
Oh yeah my truck is like 50:1 in low range. if I could get it to about 70-75 I think that would be perfect.
Truck weight: 2600-2800#
35's
4 cyl. (180 hp.)
5 speed
 

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Discussion Starter · #5 ·
that is a peppy 4cyl :thumb: I'd like to check that out some time

You touch on alot of the important points

Wheelspin is very important - for momentum.
That is why I am shooting for 50-60 with the auto. I think any lower than that will make some gears useless. This is after some brainstorming and discussing this with shane. Before that I was shooting for 75.

The auto can effectively double the gear ratio, not the 300to1 doah
 

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I run a TH400 (auto) 2.48 x2 for the torque convertor
np203 2:1
NP205 1.96:1
4:88 gears

96.88 crawl ratio some people figure the torque convertor some don't. I run a 400hp v8 and 40" tires seems low enough for me :thumb:
Plus if I don't want it so low I still have 2:1 instead of 3.96: 1 I like the optiions I have but since your stuck with a jeep :finger: j/k you don't have
the room to run dual cases.
 

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Wrench Wench
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Alicia's 66 cruiser is running

4.3 TBI 160 hp
700r4
203
toyota tcase
4.10 gears
35 bfg

3.06 * 2.0 * 2.3 * 4.1 = 57.71, and if you figure times 2 for the torque multiplicatin in the converter, around 114:1, can't wait to get it on the road this summer

My XJ isn't nearly as good yet

4.3 vortec 195 hp
4l60e
233c
4.10 gears
33 tires (soon to be 35's)

3.06 * 2.72 * 4.10 = 34.13:1 w/tc 68.26 with 4:1 in the tcase and tc 100:1



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never mind I found it. im sitting at 24.73:1 :scared: That sounds bad but ah what the hell. unless you count the TQ like the rest of them are

weight of rig = lots :finger:

number of cylinders = 8 adds up to 460 cubes

Size of tires = fooorty twos
 

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I was at 80:1 with my zuk 3.625 1st 4.16 t-case 5.43 diffs I really liked it the zuks need more reduction than some though because of the motor. I could still spin the tires pretty good but in the mud I was in mostly 4th or 5th. On an auto it makes a little difference how much torque you are putting out. Sometimes you can't flash the converter (i.e. reach stall speed for a given input) that not only doesn't allow you to get over something it creates massive heat very quickly which is a large concern for autos. The ratio in my blazer was only like 20: 1 with the 4.10s won't be much higher with the 4.56s considereing I went up in tire size too. If I was to offer a final word I would say between 70 and 100 to 1 with a manuel and 30 to 50 to 1 for an auto more if you are into rocks and less if it is an all around rig :rotfl: :rotfl:
 

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Discussion Starter · #11 ·
Lumpdog said:
Alicia's 66 cruiser is running

4.3 TBI 160 hp
700r4
203
toyota tcase
4.10 gears
35 bfg

3.06 * 2.0 * 2.3 * 4.1 = 57.71, and if you figure times 2 for the torque multiplicatin in the converter, around 114:1, can't wait to get it on the road this summer
This is the number that I am shooting for. I like your dual case idea - have to see that when you are done.
I put stars next to the ideal ratios, and a double star next to the best one. I still plan on getting that 700r4 built so keep one of those K cases around for me. I am good for it.
 

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Crawl Ratios

Thanks...still learning this "posting" stuff, bear with me if i screw it up...

Engine is 350 chev TBI, trans is SM465, TX Case is Dana 300, axle ratio is 5.38, Dana 44's, spool in rear, Detroit in front.

Will have the axle moved back 6" soon and moving the front up about 4" later this year. It's a "trailer queen" now...don't want no tickets :oops:

I am seriously considering a Turbo 400 trans. What are the pros and cons of going from what I have to the "slush box"?
 

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Discussion Starter · #17 ·
I am set on going auto - for these reasons:

I go through clutches very often. I am to a point where driving becomes more important than shifting. I also like the torque build up of an auto, which transitions smooth enough to not break stuff. I need the OD of the 700R4 because mine goes on the streets everyday. This is also part of the reason for auto for me. Daily driving is not fun and shifting is even less fun. I dont know how fast this change will go for me, but I am on the trail towards it. Yours would be a fast change with the bowtie drivetrain in there already. Mine is still all jeep.
 

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gripguru said:
I am set on going auto - for these reasons:

I also like the torque build up of an auto, which transitions smooth enough to not break stuff. .

Who ever told you that is a LIAR :rotfl:
 

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A 400 would definitely be a stout transmission to put in there, BUT the 400 is longer, and has a higher first gear that a TH350, and a TH350 can handle all the power you can throw at it from that TBI 350

The TH350's and TH400 use the same converters, so there's no loss in strength there, and with a good shift kit and good build, they are way tough. But, as with any automatic; neutral drops and high rpm reverse to drive shifts will kill them quick! I prefer automatics also in my rigs, have driven both, not rockcrawling, but most other types of terrain.



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I run the TH350 behind my Big Block and it does fine. I do run lots of cooling and a shift kit as well. I keep a very close eye on the tranny temp guage. It cheaper to get the TH350 so I went with that.

I have killed 700r4 though. To give it some credit, I did overheat it real bad a few times though.

I wouldnt mind getting rid of the BB and go to a Vortec setup with a good 700r4. Someday maybe.



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