700r4 swap

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Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

700r4 swap

Post by sierrablue »

So since I'm about ready for college, I'm gonna be doing a lot more cruising in the near future. I know that a diesel 700r4 will bolt up directly to the B350, no adapter ring needed (which is actually a step up from the nailhead TH400 Jeep used originally, with an adapter ring)(Why????? Come on Jeep, they literally make a TH400 that bolts to the Buick from the factory, just put the shorter output shaft in :roll: ). I know the shift linkage will all work pretty easily, and the TV hanger is going to be a pain to set up. Also with the cost of the adapter for the D20 to the 700r4, while I'll want to have the D20, it'll probably be cheaper and easier to just use whatever Chevy tcase comes with it. And obviously drive shafts will have to be replaced. 60 mph is ok without the O/D, not ideal, but OK (doesn't downshift ever, which is nice IMO), but some of the stretches have a speed limit 75. I'd rather not spin the engine that fast (3200 or so, right at the peak torque) for 4 hours straight if I don't have to.

My question is about the added length. Does that create clearance issues with the gas tank? I was just under there today and it looked like I had about 6-8" between the D20 and the tank, but I just want to be sure. If I do that, it'll be an expensive swap to start with, and I do NOT want to get it half way in and realize I have to modify the fuel tank for it to work.

I'll probably figure out TBI or something instead if the O/D tranny has no chance of working.

Thanks guys!
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
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Yeller
Posts: 1521
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Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

Yes it’s a shame they didn’t use the BOP t400 but I bet the nailhead 400 from Cadillac was cheap lol.

The 700 that was behind the 5.7 diesel would be low on my desire list of the 700’s. The 6.2 diesel used the standard 90 degree GM bell housing. It has the small input and lacks the later and much improved hydraulic circuits, not to mention rare. BOP to standard 90 degree GM adapters are very inexpensive.

https://www.amazon.com/gp/aw/d/B07Y65FR ... p13NParams

That opens up a much larger pool of transmissions.

I get not wanting to spin the motor at 3200 rpm for hours. 700 solves that. As for transfer cases, I’d be comparing a Dana 300 with a 27 spline input to the cost of the Dana 20 adapter. Better case and with a clocking ring to raise the front output to the correct location bolts to the stock 700 adapter, now only 5 bolts line up but I can assure you it works, I personally own 2 very abused vehicles set up this way, one with a d300 and one with an Atlas. The other option is put a clocking ring on the 208 or 241 that came on a 700r4.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Sweet! I hadn't thought about the D300 bolting right up--that seems like a good plan. That adapter is really cheap...maybe I should just bite the bullet ok that.

So there's no issue with the gas tank?
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Yeller, since you clearly have experience with this, what all goes into the D300 swap? How does the shifter line up with my existing floor pan? Should a stock D300 be plenty strong for my mostly street application?
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
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Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

I have no idea about how the shifter lines up or interference with the gas tank, shouldn’t be I don’t think the combination is any longer than the 400/20 combo you’re running now. For your uses a D300 is more than sufficient. You also gain a lower low range plus the lower 1st gear of the 700, enough different to be noticeable. 700 is also more efficient at transferring power so it will feel more powerful, it consumes less HP to operate.

There are 3 of ways to adapt it. There are 27 spline inputs available, eliminating the need for an aftermarket adapter. Advance Adapters sells a 23 spline output shaft for the transmission and adapter to make it work, this option is 2-1/2” shorter if I remember correctly. Then the is the adapter/spud shaft arrangement similar to the stock 400/20 adapter, only instead of a shaft that holds the input gear it has a 23 spline output to match the 300.

The 300 that I’m running has a spud shaft, it has been used hard enough to twist the H on the slip yoke that holds the u joint on the drive shaft. They are stout little units stock, this particular unit has the upgraded 32 spline outputs, so the weak link is the low range gear set. It is a significant upgrade over a 20.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Sweet thanks! I have friends that are all "don't get the 700r4; it has a weak overdrive gear," and I thought about it, and I don't see this Jeep doing much hard-core towing. Also if it's working hard enough that it's going to break the overdrive, I suspect it's going to be in 3rd when I'm working it that hard anyway.

Thanks for the verification on the D300 stuff, Yeller. I figured the D300 was plenty strong based on the swaps I've seen done with it, but still all it really came in was Scouts and CJs, so I just wanted to be sure.

See, the thing about the 700r4 having a lower first gear is that I don't need a lower first gear--with the first gear I have, I can't quite spin the tires on dry pavement, but can get darn close, which I personally like. But I'll get used to it 😉
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Contacted a guy about a D300 on Craig's list...he wants $1500 for a D300 with 75k miles on it. He must be joking :lol: :lol: :lol: :lol:
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

sierrablue wrote: Thu Feb 09, 2023 11:49 am Contacted a guy about a D300 on Craig's list...he wants $1500 for a D300 with 75k miles on it. He must be joking :lol: :lol: :lol: :lol:
for sure..... maybe 1500 for a completely rebuilt unit by someone with a warrantee.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

I'll give him 20% of that...

Everything else he said was an OK answer, but the price tag made me go "Uh, what?!" Although he said it "wasn't rusty"--is that a problem the D300s have somehow, they rust through the case or something? Or does he just think it's some jewel because it has no surface rust? :roll:

If it has no surface rust but does have 75k, my bet would be that it's covered in grease instead, which, isn't really isn't much better.

Looking again, it's just 1200 they want for it. As if that's better :roll:
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Any other ideas on an OK part-time (or even full-time, as long as it has 2 and lo) case? I want something not obnoxiously heavy. If anyone has a D300 they'd sell cheap then I'll take it, but those things are stupid expensive now. I don't care too much about chain drive vs. gear driven--as long as it bolts up, is pass drop, fits, and I don't have to constantly be fighting it, I don't care too much. Well, it has to have a mechanical shift linkage. I'm not messing with electronic tcases, and sure as heck not messing with vacuum.

It's looking like there's a shop not TOO far away that sells rebuilt 700r4s for like $650 plus a core charge, you tell them what you need. The same shop does TH400s so maybe I could get some/all of the core charge back with mine. The adapter from the SBC to the BOP pattern is ~$40 so that's not too bad. Oh, and there's a 700r4 w/a driver's drop tcase on Craig's List for like $400 that is closer than that shop.

Tcase ideas would be much appreciated. If possible I want to put the shifter in the factory hole, IDC about the shift pattern too much.
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

There’s only a few options for passenger drop and is bolt on for a 700. NP208 from a square body chevy or an NP241 from a 88-91 suburban or K5. That’s really all there is. 205 is another option but requires the correct aftermarket parts from Novak or Advance Adapters. Or break the piggy bank and rob your college fund for an atlas.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Do the 241s/208s have any huge issues with them? Anything that's going to cause me a ton of trouble?
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

none really. they both have issues with the sycronizer for shift on the fly, not an issue with your set up and they function just fine without it. If you can find one, the 241 is better, it is pressure lubricated but nothing wrong the the 208.

Either will need a clocking ring like this one to get the front output out of the dirt, it will hang down 4 or 5 inches below the frame rail without it. I am running a 241 in my truck currently, unfortunately it will not fit your 700r4 dreams, it fits a 4l80e.

https://www.offroaddesign.com/6-bolt-cl ... ments.html
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Is that an issue with the 700R4/241 together out of an '89 K5? thej10guy has a K5 and we've been talking about my taking parts from that (TBI, tranny, and tcase) (not 100% it's a 700r4 but based on my research it should be)--nothing final yet but I'm curious.
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

That k5 is the perfect donor. And yes that is the issue. As long as no one swapped it out, it will have the best generation of 700r4 and 241

Another tid bit, if you do this and use a 241 only fill the case with 2 qts of ATF. If you fill it to the full point on the case after clocking it will be way over full and spew out the vent like a geyser. Same with a 208 but I think it’s 5qts, can’t remember for sure.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Thank you for all the patience and info Yeller! I'm sure somewhere somebody has asked this stuff before, but I couldn't for the life of me find it.
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

sierrablue wrote: Fri Feb 17, 2023 5:19 pm Thank you for all the patience and info Yeller! I'm sure somewhere somebody has asked this stuff before, but I couldn't for the life of me find it.
No problem, always happy to help. Someone should benifit from me spewing a lifetimes worth of mechanical trivia.

What I really find funny is how things we tried and failed decades ago are making a resurgence with little research into history and ignoring those saying it won’t work. Unfortunately it applies to way more than just mechanical design.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Yeller wrote: Fri Feb 17, 2023 6:45 pm
sierrablue wrote: Fri Feb 17, 2023 5:19 pm Thank you for all the patience and info Yeller! I'm sure somewhere somebody has asked this stuff before, but I couldn't for the life of me find it.
What I really find funny is how things we tried and failed decades ago are making a resurgence with little research into history and ignoring those saying it won’t work. Unfortunately it applies to way more than just mechanical design.
Yeah, you're making it a piece of cake for me to figure out how to put this together :-bd

Another question:
How do you have your shift linkage set up on your 241? Is your truck pass drop still? I'm curious about how you did the shift linkage. I don't want to have to modify the floor (and buy a new section of carpet) if I don't have to.
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 700r4 swap

Post by Yeller »

Hahaha, glad my driveling helps😊

Shifter is very simple. Yes mine is still passenger drop. I relocated mine but could have left it in the original location. The 241 just needs a simple lever to shift so a simple pivot and rod is all that is necessary.

Give me a few days and I’ll try to get you more pics if I can remember to take them as I take it apart. More to come on that, has been long awaited 😎😉
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The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: 700r4 swap

Post by sierrablue »

Awesome, thanks Yeller! I'm looking forward to what you're doing to it ;)

Ugggg now...someone...here at home is telling me that I shouldn't bother to spend the money on upgrading the combustion setup if I want to make it electric. On the one hand, yeah absolutely. On the other hand, there's no way I can fund that, and I don't know when I'll be able to, so I'd like to take good care of it, so that with any luck, I won't have to figure out what to do when it craps out on me and I'm not ready to do an entire EV conversion. And I mean, 75-80 mph for hours (somewhere in the 3100-3300 RPM range). The person who said this has talked about putting an overdrive in it previously. I don't understand, but we'll see what happens. I think the O/D is more critical than the TBI.

We'll see what happens.
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.
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