'72 crawler build

[68rockcrawler]

Can you tell for sure where the gas is coming out? If it's at the top of the filler neck then it has to be the cap. A new gas cap is only around $10. My cap has a gasket on it.

 

[CW72]

The new top looks great Colin. Who makes that top?
Kenny

It's a rampage. I'm liking it so far. But like everyone says, don't drill the hole for the door post, it's way off. Also get some real #14 sheet metal screws. Provided ones are complete garbage.

 

[CW72]

Can you tell for sure where the gas is coming out? If it's at the top of the filler neck then it has to be the cap. A new gas cap is only around $10. My cap has a gasket on it.

I know it's coming from the top, but I can't tell if it's back pressure pushing the gas up and out or if it's just flowing there. The return tube is right there at the bottom of the filler neck by the opening and that's what I'm suspecting. I'll try a new cap for the hell of it, is that something advance would have or do I need to order online?

 

[68rockcrawler]

Advance has a whole rack of gas caps. I bet they have one that will work, but I've never bought one from them so I'm not sure.

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[CW72]

Advance has a whole rack of gas caps. I bet they have one that will work, but I've never bought one from them so I'm not sure.

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I was able to get one through them, picked it up this morning. There's a rubber gasket in this one so hopefully that solves it. I'll report back after Sunday, getting out to do some wheeling again.

 

[CW72]

I do not internet enough. Few things done, main one was a shave cover for the 14b. Fighting a small wobble around 45-50mph, got a small amount of play in drivers wheel that may be causing some of it, everything else as far as I can tell is tight. I reefed on the track bar brackets, don't think it's that.

Going over and over my doubler considerations. Just plain can't decide if a c6 and 203/205 is the right way to go, or stick with my c4 and go with a 2 speed atlas. Looked at STaK for a while just to find out they were out of business, looked into klunes and black boxes, I'm totally baffled by the influx of information. The atlas option is a little more appealing because of space and weight, but that sticker price is daunting. I'll be on the lookout for a used one.

Thing is, I've already got the doubler, do i really go back and get something else or just run it?


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[Mountain Ram]

Atlas cases aren't cheap, but they are worth the money if you have it to spend. Having the doubler on hand, you could try to run it or try to sell it to get some of the Atlas funds. Used Atlas cases are still pricey and you have to watch for the abuse...

I have installed an NP231/241 doubler, which is essentially the 'black box' type of approach. It uses the range part of an NP231 case with 2.72:1 low range. While shorter, lighter and lower geared than the 203/205, it still presented challenges in rear driveshaft length. I extended the rear WB by 8" and I use the full range of a 1410 U-Joint on the 27" driveshaft (running 16" coilovers on a 4link suspension). Of course this is behind the C6 which is longer than a C4, but should be more stout (if cooled properly). Of course not everyone needs 7.4:1 low range (I am runnning 44" tires).

The black box in front of the 205 will give you some great gearing options (1:1, 2:1, 2.72:1 & 5.4:1), is shorter and lighter than the 203/205 (geared 1:1, 2:1 & 4:1). It requires some special work to fit 31 spline Ford applications, but I think Northwest Fab can help with that and its half of the Atlas price.

Funds and space considerations would be the two primary issues. If you can fit the 203/205 and not rip apart short driveshafts, this would be your least expensive option (since you have it on hand).

 

[68rockcrawler]

I do not internet enough. Few things done, main one was a shave cover for the 14b.

Which 14b shave cover did you use? I've been shaving mine pretty successfully in the rocks to where it's now only a 13 bolt. I've been wanting to shave it for real.

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[CW72]

Atlas cases aren't cheap, but they are worth the money if you have it to spend. Having the doubler on hand, you could try to run it or try to sell it to get some of the Atlas funds. Used Atlas cases are still pricey and you have to watch for the abuse...

I have installed an NP231/241 doubler, which is essentially the 'black box' type of approach. It uses the range part of an NP231 case with 2.72:1 low range. While shorter, lighter and lower geared than the 203/205, it still presented challenges in rear driveshaft length. I extended the rear WB by 8" and I use the full range of a 1410 U-Joint on the 27" driveshaft (running 16" coilovers on a 4link suspension). Of course this is behind the C6 which is longer than a C4, but should be more stout (if cooled properly). Of course not everyone needs 7.4:1 low range (I am runnning 44" tires).

The black box in front of the 205 will give you some great gearing options (1:1, 2:1, 2.72:1 & 5.4:1), is shorter and lighter than the 203/205 (geared 1:1, 2:1 & 4:1). It requires some special work to fit 31 spline Ford applications, but I think Northwest Fab can help with that and its half of the Atlas price.

Funds and space considerations would be the two primary issues. If you can fit the 203/205 and not rip apart short driveshafts, this would be your least expensive option (since you have it on hand).

Gives me a bit to think about. I have space concerns first and foremost. A better transfer case can certainly wait, however badly I want it. Selling the doubler to repurpose the funds may be the best idea. I'd rather only do one swap and build one set of transmission mounts, etc. I have 10" of stretch on mine, but I'll still have a 2 foot driveshaft all said and done. Still leaf sprung for now so I won't use as much range as you but that could likely change one day too. Will however stay with 40s. Need to look more into what low I should run keeping that in mind. I'm thinking around 4-5:1 should put me in a pretty good spot.


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[CW72]

Which 14b shave cover did you use? I've been shaving mine pretty successfully in the rocks to where it's now only a 13 bolt. I've been wanting to shave it for real.

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I went with the one from Barnes. I have been doing the same with mine, it advertises chopping off like 1 1/4" or something and I may have gotten like 3/8". Went that way mainly because my factory diff cover was trashed. Peeling up like a tin can and leaking everywhere. Decided to just add some beef and grind the bottom of the pumpkin smooth.
A true shave was far more than I was willing to take on right now. Wasn't going to yank the whole rear out to plate it etc etc.


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[Mountain Ram]

Gives me a bit to think about. I have space concerns first and foremost. A better transfer case can certainly wait, however badly I want it. Selling the doubler to repurpose the funds may be the best idea. I'd rather only do one swap and build one set of transmission mounts, etc. I have 10" of stretch on mine, but I'll still have a 2 foot driveshaft all said and done. Still leaf sprung for now so I won't use as much range as you but that could likely change one day too. Will however stay with 40s. Need to look more into what low I should run keeping that in mind. I'm thinking around 4-5:1 should put me in a pretty good spot.


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Gear ratio becomes personal preference at some point. My doubler was in my Dodge Ram truggy. With 44" tires and an auto trans, it worked perfect. Since I am running a similar setup in the Bronco, I figured it should work as well. Having the 'high' low range is a great option for when I need wheelspeed, but still need to push the 44s.

My Dodge was about 93:1 low and the Bronco will be about 98:1 with only the axle gears different. I have seen guys with 300:1 which is way overkill (IMHO) and rigs that run 50:1- a minimum for 'crawling' in my opinion/experience (I am sure some will have differing opinions).

 

[68rockcrawler]

This is a very interesting conversation because I'm wanting to switch to an automatic and a guy was telling me the other day how beneficial a doubler would be. I have a T18 manual and stock Dana 20 right now and 5.38 axle gears. If I remember correctly my low is about 79:1 which I think is perfect. I barely ever find myself wanting lower crawling gears.

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[Mountain Ram]

This is a very interesting conversation because I'm wanting to switch to an automatic and a guy was telling me the other day how beneficial a doubler would be. I have a T18 manual and stock Dana 20 right now and 5.38 axle gears. If I remember correctly my low is about 79:1 which I think is perfect. Thanks barely ever find myself wanting lower crawling gears.

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Assuming your T18 has the 6.32 first gear, the Dana 20 is the 2.46 ('68 T shift)- you should have about 84:1 crawl ratio. The T-18 could have a numerically lower ratio (4.02) and the D20 could be 2.34:1 ('73+ J-shift).

Auto transmissions have an additional reduction due to torque converter slip- I have seen estimates of 2x on overall gearing (stock type torque converter). In my crawler- this would put me just shy of 200:1 down to 98:1 in first gear.

 

[CW72]

Doing a lot of reading about the blackbox-I and I think it may be a viable option. I could go with the c4 and AA adapter which runs almost $600, or I could go with my c6 that has a reverse vb and no adapter. I'll have to check which adds more length but I may lean the c6/bb-i/d20 route..


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[68rockcrawler]

Did you read Gravy's Blackbox install thread? I used to wheel with him when he still had his Bronco and his setup worked really well. The Blackbox does sound like a great option that I might have to consider also as I plan my transmission swap.

I have heard conflicting stories regarding using a dana 20 in a doubler, specifically whether they can handle that amount of torque. I have heard of guys cracking cases in half and of course breaking stock output shafts and then other guys that beat the snot out of them with no problems. I have the heavy duty output shaft so I'm not worried about that part.

 

[CW72]

Did you read Gravy's Blackbox install thread? I used to wheel with him when he still had his Bronco and his setup worked really well. The Blackbox does sound like a great option that I might have to consider also as I plan my transmission swap.

I have heard conflicting stories regarding using a dana 20 in a doubler, specifically whether they can handle that amount of torque. I have heard of guys cracking cases in half and of course breaking stock output shafts and then other guys that beat the snot out of them with no problems. I have the heavy duty output shaft so I'm not worried about that part.

Yeah actually I did go through that in my searching, I was wondering how it was holding up after a few years. I saw he did the upgraded tailshaft and I think the 300m shaft too? I don't mind putting a little into the d20 if it will hold up to the abuse. Mine is totally stock right now so along with other things I'll be twin sticking and rebuilding it. I'm going to look into other gearing options as well to see what's offered. I have the t shift so I'll end up with 6 something for the transfer case alone.

I will probably call NWF one day and go through what my options are and see what they recommend.


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[68rockcrawler]

He only ran it for a few years before he sold the Bronco. I never heard of any problems while he had it though. If you're looking in to the upgraded output shaft and gears in the Dana 20 plus a black box you're in Atlas price range. That is if the other gearing options you're talking about are gears in Dana 20. I don't think you'd need those in addition to the blackbox.

I think the 300m shaft is the output shaft. I think that's the only shaft upgrade available for the Dana 20.

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[CW72]

He only ran it for a few years before he sold the Bronco. I never heard of any problems while he had it though. If you're looking in to the upgraded output shaft and gears in the Dana 20 plus a black box you're in Atlas price range. That is if the other gearing options you're talking about are gears in Dana 20. I don't think you'd need those in addition to the blackbox.

I think the 300m shaft is the output shaft. I think that's the only shaft upgrade available for the Dana 20.

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Hm. I'll look at the pricing. One thing I like still about the blackbox is I can adapt it to an atlas 2 if and when that comes about. Becomes a 4 speed then. Although it may be cheaper to just buy the 4 speed to start..

I'm going to sit down and come up with some solid numbers and report back.


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[SpareParts]

Backbox and a 205 combo. It will be a lot stronger than the D20. I like the choices in gearing... I have the DIY Behemoth, same as a blackbox but NLA. The 2.0/2.69/5.33 it's nice to have options!

 

[CW72]

Backbox and a 205 combo. It will be a lot stronger than the D20. I like the choices in gearing... I have the DIY Behemoth, same as a blackbox but NLA. The 2.0/2.69/5.33 it's nice to have options!

I had seen that come up a few times, I know the 205 is a beast. Unfortunately I don't have one of those by itself, I have the doubler already built. I know those can be had for cheap, but man they are heavy. I like the options too, another reason why I may just lean atlas. I can get 10 something out of the box. Bolt it to my c6 and run with it.

Leading to my trans decision, I think I may do the c6 over the c4. My c4 has about 4000mi on a rebuild and a shift kit, but my c6 has a Pro-Super rebuild kit, full manual reverse vb from TCI Transcat I believe (kind of a bad rep I know), and a B&M Tork master 2000 torque converter, and it's never been run since it's rebuild.


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