Gears

[c2computer]

I am sure this has been posted many time but I thought I would ask. <br><br>Running 33's or 35's (future, have 33's now). I have 3.53 gears now. When I go down hill in 4 low, 1st gear, it is like a roller coaster. Would you go with 4.10 gears and still be able to do 60 or 65 on freeway?<br><br>Also, how much better would this be off roading for crawling or would I still need to tweak the transfer case. Thanks

 

[mxpaz]

Go with 4.56 or 4.88. 4.11 are ok if you just drive it on the street. If you go up to 35's you will wish you had gone to 4.56 or 4.88.

 

[c2computer]

Well I drive it in town here and there but I want the low crawling speed and dowhill more. Is there a best of both worlds? With 4.56 is freeway driving crap?<br><br>Here is the chart, it looks they moved it...<br><br>http://www.intercotire.com/html/table.htm

 

[justinsane]

The only way to get the best of both worlds is a tranny with more gears and a wider ratio spacing. That chart should tell you what you need to know. 4.56 and 33 wouldn't be to spiffy on the freeway IMO.<br><br>Brian

 

[mxpaz]

Yeah you can put a NP435 and 4.11 gears. Or something like that. You will prob have to do something with your tranny. You can put the terra gears in like you first said and that will help some too.

 

[c2computer]

Yeah that is a little high. I am not enterning a rock crawling competition, just want to crawl more and stop running down the hill locking up the brakes trying to stop because I have no gears... <br><br>I just can't hack a new tranny, just had this one rebuilt.

 

[flint_knapper]

dang....the calculator says that when my speedo says<br>80 I'm actually doing 88!!!! I'm going to have to adjust my driving habits!!!!

 

[randall]

i have 35"s on mine, but they actually measure around 33 because htey are so worn out. I also have 4.88s, it isnt great on the highway, i can go around 65-70 but it winds pretty high, off-road and around town it works really really well though, i would go with 4.56s though since you still want comfortable highway rpms, also you could go to a automatic and forget about all that crawl ration stuff. But it wouldnt get rid of your rollercoaster problem.

 

[tonto]

I think4.11's and 33" tires and 4.56 and 35" tires are a good Highway/trail combo.<br>I have a friend who is currently running 35"s and 4.88'ss with a C-4, it sucks on the highway, way to high RPM's, I ran that combo with an AOD and it was perfect RPM'S in O.D.<br>

 

[joes75]

I'd go at least 4.56 leaning towards 4.88 myself...

 

[bpatton74]

I'm planning on going with 5.13's with my C-4 trans (90% offroad 10% getting offroad). ;D

 

[c2computer]

I think I am going to go with 4.56 with the 33's now and if I get 35's someday it will still be alright. I figure get that done, then I can always get some gears for the transfer case someday to get the crawl ratio better.<br><br>Anyone running those tera low gears? they didn't seem to add a lot of crawl ratio with a C4.

 

[Lttrbox]

Im running 4.11, 35's, C-4, stock dana 20. 3k rpms put me around 76mph. I think this is a bit high,<br>but not too bad. The rock crawling is a bit tough, wants to go a little fast so I end up riding the brakes.<br>Then I get into tranny heat, engine heat, etc.

 

[c2computer]

Lttrbox,<br><br>So it is still fast when rock crawling? What would you have done differently if you could?

 

[Lttrbox]

Yup, it goes a bit fast crawling around. Most of the time its not too bad, but some of the real<br>hairy stuff makes the adrenalin pump pretty good. But then a again Im a bit of rooky. I bought<br>this rig from my bro pretty much set up this way. Ive got a big winter coming. Im going with AOD<br>wide ratio gears (lower first gear than C-4) and an Atlas t-case (4.33, I think). Based on previous<br>runs in Cedar City and Vegas, this should get me pretty close. (oh ya, Ive heard rumors about a<br>torque converter that can help with going real slow). I guess, I would have gone lower gears, but<br>I wouldnt have known without running it.

 

[tonto]

If this is your daily driver or you drive it to and from the trail I would recommend you not go lower than 4.56 with 35” tires, 4.88 and up are going to be to low and give to high of an RPM for highway driving.
4.56 with the 33” tires your running now are going to be like night and day, and the 4.56 will be a good combo with 35’s when you get them for the street and low range off road, keep in mind the street/trail driving ratio, what % do you drive on/off-road, if you go to low you will not like driving it on the highway at 65 MPH very much.
Here is some final drive RPM’s for consideration:
33”/4.11=65 MPH/ 2720 RPM
33”/4.56=65 MPH/ 3017 RPM
33”/4.56=75 MPH/ 3482 RPM
35”/4.11=65 MPH/ 2564 RPM
35”/4.56=65 MPH/ 2845 RPM
35”/4.88=65 MPH/ 3045 RPM
35”/4.88=75MPH/ 3513 RPM
If it were I and I wanted to stay with the C-4 and 35” tires I would go with 4.56 R&P gears and swap out the Dana – 20 to an Atlas 4.3

Here are some crawl ratios for these same combo’s:
4.11 R&P =23 to 1
4.56 R&P =26 to 1
4.88 R&P =28 to 1
4.56 R&P w/ Atlas 4.3 ratio = 48 to1
I hope this is of some help in deciding what ratio to go with.
Good Luck, Francois.

 

[c2computer]

Thanks for the info, I appreciate the time you put into it. I drive it to the trail but I don't think I have ever gone over 65-70 mph in it. I don't trust the steering enough and I like to be easy on it. As far as the 26 to 1 craw ratio, is that decent, suck or a lot better than what I have now with 3.55's? <br><br>The Atlas seems like a great way to go, $$$ but maybe that is the solution?

 

[Broncobowsher]

Time to stir the pot some more....<br><br>Lets start at the other end and wor our way back. How much highway driving do you do and how comfortable do you want it to do it? Figure out how much grunt your engine has. Use the tach (get one if you don't) and figure out where the engine like to run. Where you want it to be on the highway. work your way down from there. <br><br>It is easier to get lower gearing then it is to go high. If you over gear, there are 3 options 1) regear again 2) add an overdrive 3) bigger tires.<br><br>If you need to go lower there are more options then I can think of right now<br><br>As for what I am running, it is a 351/4R70W/Tera low-ed D20 and 4.88 gears. Tires are 33's<br><br>I can cruise comfortably down the freway thanks to the .7 overdrive. That wonder brings the 4.88 gears down to an equivalent 3.42.<br><br>I was running an NP435. that is a good transmission. Drives kind of like a truck. That is just fine most of the time. I am getting lazy and went automatic. What the NP435 taught me is that it is best to have a wide spread of gears.<br><br>For my opinion, KEEP the 3.50 gears for running down the highway. Replace the old 3 speed with an NP435. The 2nd gear in the NP435 is a bit lower then the old 3 speed. it will give you the equilivent of about a 4.10 gear from a stop while keeping the 3.50 highway gear. Plus you will get a granny. It is a cheap swap. Save the money doing the gear swap and get a 4 speed.

 

[tonto]

R&P 1st D-20 low range = Crawl Ratio
C-4 3.55 X 2.46 X 2.34 = 20 to 1
NP-435 3.55 6.69 2.34 = 55.57 to 1

 

[Broncobowsher]

NP435 1st gear 6.69, not 4.78 (is the close ratio box?)<br>C4 multiply in about another 2 for the torque convertor. you just don't get it in compression braking.<br><br>Anything beats the stock 2.99 first.