Hey all,

Here is the current list of hardware in the truck: 1978 Bronco, 351M, C6, 205, Dana 60/14 Bolt, 5.13:1's, locked f/r, and 4-linked f/r. This truck will be getting a mild 460 (roughly 450-500hp) this winter.

I would like to have a little lower gearing, but my 4-link crossmember in the rear doesn't allow me the room for a doubler.

First of all, is switching from the np205 to the 1345 or 1356 a good idea or not, and if so, do I need a different tailshaft housing to adapt from the C6 to the 1345 or 1356?

I have searched some on this, and it seems like some people say that you can simply unbolt one t-case and bolt the other one in, and some say that you do need a different tailshaft housing.

Any help is appreciated!

Thanks
Adam

should bolt right up but you will want to find one with a fixed yoke on the back

should bolt right up but you will want to find one with a fixed yoke on the back

X2, same bolt pattern and spline count. 80's Bronco's are good source for fixed yoke. The BW1345 is definetly not as strong as a NP205 and they are chain drive but the lower gears are appealing. The upgrade is the BW1356, much more common, aluminum case vs the BW1345's magnesium case and a better internal pump mount but it's not really any stronger than a BW1345 and they have the same gear ratio.

With 500hp I'd think I'd stay away from either one.

Edit: Ford fullsize t-case adapters are transmission specific, in other words it is built for the transmission not the t-case, asfaik all are 6 bolt round pattern and 32 spline shaft. Some require a little grinding for shift rails and such but on the whole they will work for any married full size case Ford used in the '70's-'90's. ( Except the bastard dog D21. :D )

Thanks for the quick replies guys.

I actually have 1 extra 205, 1 1345, and 1 1356. Both the 1345 and 1356 are fixed yoke.

I agree with the 500 hp comment though. The 205 definitely lacks in the gearing department, but it is bullet proof. Right now the case in the truck is making a pretty serious vibration (np205), but it just won't give up!

If Lomax would come out with the Ford version of their 3:1 kit for the 205, my problems would be solved.

So what say the PBB? I have searched quite a bit on the 205 here, and it seems my best bet in the end may be to suffer with inadequate gearing until I can afford a Stak or Atlas.

With my application (big tires, bigger hp's in the future, heavy truck, etc...), it seems like it may be smartest to stick with the 205 for now.

As always, any input is appreciated.

Thanks
Adam

Well if your 205 is about to puke it's lunch and you have a 1356, pay up your AAA Gold Card and run the 1356 for awhile, see how it likes it. I'd be interested to know.

The 1345 actually has a bigger chain than a 1356, and is pretty easy to find in fixed yoke, I have yet to see one that wasn't(80-86 BKO's and F250/350's had em, F150's ran 208's.)
Yes, it is a direct bolt in swap, no changes required.
As for stregnth, considering what the diesel guys do to them and the power they put through them, if the chain isn't worn the hell out, I wouldn't be worried about running a 500hp gasser through one. I have personally abused the heck out of the 2 I have in trucks, inlcuding grossing about 18K for 200 miles on the front axle...
Since it's pretty much a direct swap, give it a shot, worst case it breaks, and you put the 205 back in.

Once again, thanks for the replies.

I wouldn't mind giving the 1345 a try, and like 82F100SWB said, I can always go back to "old reliable" if the 1345 doesn't seem to hold up.

One question, and this is probably a stupid one, but driveline lengths will have to change, won't they?

From looking at the input to the 1345 and the length of the case compared to the 205, it seems like the front shaft would have to be lengthened, and the rear shaft shortened.

Is this right, or am I crazy?

I have spare shafts I can piece together, but I wouldn't want to cut apart the shafts currently in the truck and redo them, considering that I may put the 205 back in eventually.

So, like I said, if anyone has switched from a 205 to a 1345, did you have to adjust driveline lengths, or was it literally plug and play?

Any input is appreciated.

Thanks
Adam

Edit: Ford fullsize t-case adapters are transmission specific, in other words it is built for the transmission not the t-case, asfaik all are 6 bolt round pattern and 32 spline shaft. Some require a little grinding for shift rails and such but on the whole they will work for any married full size case Ford used in the '70's-'90's. ( Except the bastard dog D21. :D )

isn't the input shaft(trans output shaft) for the t-cases all 31 spline? i always thought they where.... i know the output yokes on the 205 and some others are 32 spline..

but yes i think you would have to lengthen the front shaft and shorten the rear..

isn't the input shaft(trans output shaft) for the t-cases all 31 spline? i always thought they where.... i know the output yokes on the 205 and some others are 32 spline..

but yes i think you would have to lengthen the front shaft and shorten the rear..

Cripes, I think you might be right.....I always get the spline shit mixed up. :rolleyes:

While the 1345 is not as strong as the 205, it will handle 500HP. I have been running one in my buggy for about three years now with a 500HP stroker motor and 49 inch tires. I DID break it once last fall- the rear output shaft snapped, but I believe it was a fatigue issue caused by a combination of the heavy square driveshafts and those offset trunnion Tom Woods U-joints that I have to run for yoke clearance. Before I built my rig, I was told that some of the more serious straight line mud racers in the area were running them because of the great 2.74 low range and the MUCHO lighter weight compared to the 205.

Run it, you wont be dissapointed. Even if you do break it, they are stupid easy to swap out.

Nothing against 460's ..but for the price a 500HP 460 you could buy an Atlas or STaK, and a few extra 351/400's. problem solved... next :flipoff2:

Nothing against 460's ..but for thae price a 500HP 460 you could buy an Atlas or STaK, and a few extra 351/400's. problem solved... next :flipoff2:

Ouch, I hate it when you use logic.

Guess I dont see the logic???

Drop a shitload of money on a bling-bling transfercase when a much cheaper alternative will do the job?? Oh thats right, so you can brag about your expensive transfer case. Only thing the BW1345 has going against it is it can't be made to do front digs- if he can live without that, theres no reason not to use it.

and a 500HP 460 is fairly affordable really.

go ahead and flame away on me, I guess.

Some require a little grinding for shift rails and such but on the whole they will work for any married full size case Ford used in the '70's-'90's. ( Except the bastard dog D21. :D )

None of the Dana cases will bolt to an NP/BW adapter. Neither the 20 or the 21. (The 24 was never offered in a married style)

None of the Dana cases will bolt to an NP/BW adapter. Neither the 20 or the 21. (The 24 was never offered in a married style)

not 100% true.. some of the older F100s(i think pre 74) had a D21 in them with a NP435. if i remember right it was just a 4 wheel drive 2 wheel drive t case.(just a 1:1) it had a differednt bold pattern and splines than the 203, 205, and such. also an aftermarket adapter can be purchased to use the D20 behind a NP435.. but i'm sure you where talking about factory stuff so that does not count.

not 100% true.. some of the older F100s(i think pre 74) had a D21 in them with a NP435. if i remember right it was just a 4 wheel drive 2 wheel drive t case.(just a 1:1) it had a differednt bold pattern and splines than the 203, 205, and such. also an aftermarket adapter can be purchased to use the D20 behind a NP435.. but i'm sure you where talking about factory stuff so that does not count.

All I was saying is that the bolt pattern on the Dana cases was different than that of the New Process cases and the Borg/Warner cases which are identical.

I've seen D-21's(single speed case) behind NP-435 in F-100. I'm told they were the only option on 3-speed 4WD, but I have never seen a 3-speed Ford 4WD except the Early Bronco's with the small I-6's. I know the D-20 fits behind the C4, and I would assume the Ford 3-speed since many were offered and I doubt they were all single-speed 4WD. If I'm not mistaken, the D-20 and D-21 don't even share the same bolt pattern. I'm wondering now though, was the D-21 the first of what's now the standard Ford t-case pattern? Hmmmmm. Doesn't matter, nobody's talking Dana cases here. Should have stayed out of it, as usual.

All I was saying is that the bolt pattern on the Dana cases was different than that of the New Process cases and the Borg/Warner cases which are identical.

I've seen D-21's(single speed case) behind NP-435 in F-100. I'm told they were the only option on 3-speed 4WD, but I have never seen a 3-speed Ford 4WD except the Early Bronco's with the small I-6's. I know the D-20 fits behind the C4, and I would assume the Ford 3-speed since many were offered and I doubt they were all single-speed 4WD. If I'm not mistaken, the D-20 and D-21 don't even share the same bolt pattern. I'm wondering now though, was the D-21 the first of what's now the standard Ford t-case pattern? Hmmmmm. Doesn't matter, nobody's talking Dana cases here. Should have stayed out of it, as usual.

O ok.... you are right about the D20 and D21 not having the same bolt pattern though.

just make sure you open up the 1345 and make sure the pump hasn't ate through the case..

The only other thing that wear in the 1345/56 is the planetaries..

well, my cousin runs a 1345 in his race truck.. 620HP BBF, 38x11 boggers, and it will pull the front tires on good launch. He has 4 years on the same T-case.. they are pretty tough..

Well, it sounds like running the 1345 is definitely worth a shot.

I am going to work on the truck tomorrow. I am VERY sure the 205 is the source of the vibration, but I am going to verify that first.

After that, I am going to try and throw in the 1345.

After reading this thread, I am pretty sure this is correct, but the output splines for a 1345 and 205 do match, correct?

I will probably need to swap the yokes from the 205 to the 1345 (the 205 has double cardan joints on the front and rear outputs).

Thanks for all the replies guys.

I will try and get her together this weekend, and see what difference the increased gear reduction gives me!

As always, input is appreciated.

Thanks
Adam

Yep, your yokes should swap over. I can't remember if the seals are the same ID or not, but, you can get the right ones to suit without getting into oddball parts..

Yokes will swap, but a different seal is required. If you have a parts store that is worth a damn, they should have a book to look up the dimentions that you need for a seal and order it. Or I can get you a part number if that doesnt pan out for you. I am shure you have figured it out already that you will lose a bit of rear driveshaft length due to the BW1345 being longer.

hey guys i have just about the same problem i have a ford f 150 and i have a bw 1345 that pops out of 2wd and wont do anything in 4hi so ive been driven it in 4lo so i aquired a bw 1356 and 2 np 208 and i was wandering what would it take to but the bw1356 in and would it be possible to put one of the 208s for a doubler any help would be great .

hey guys i have just about the same problem i have a ford f 150 and i have a bw 1345 that pops out of 2wd and wont do anything in 4hi so ive been driven it in 4lo so i aquired a bw 1356 and 2 np 208 and i was wandering what would it take to but the bw1356 in and would it be possible to put one of the 208s for a doubler any help would be great .

It would probably be easier to fix the 1345.. It probably just needs new shift fork inserts or a shift fork.

You can bolt in one of the 208's with no changes provided they are fixed yoke. The 1356 is a little longer, even in fixed yoke form, so, driveshaft changes may well be necessary.
As for doing a doubler, the output on a slip yoke case will slide right into the input... If you have the driveline legnth to fit it, you just need to make up an adapter and trim down/seal the front case,