I am very slowly repowering my '91 SAE Bronco with a 4.6L Triton V8 and 4R70W transmission from a 1997 F150. I am using a BW1356 manual shift xfer case and I've run into a snag on the driveshaft. I obtained a driveshaft from a Bronco with an AOD trans (my Bronco had the E4OD) which is the correct length, but the flange where it bolts to the xfer case is different. Both driveshafts have a double-cardan joint here, but the AOD shaft has the type of u-joint that bolts to a yoke on the xfer case, whereas the E4OD shaft has it's own flange that bolts to the xfer case flange. My xfer case is set up to take the latter so I had planned to just pull the flange off of the old shaft but the dang ball joint in the middle is different.

The easiest thing to do would be to find a yoke for my xfer case that will take the AOD shaft, but I have never seen one of these before with a double-cardan joint on it. What years would this be on? Is this going to be on the BW1346 case maybe? I can get pics if that is needed.

 

The transmission has nothing to do with it. In 90' Ford went to the flange style on the T-case. The problem is the shaft that the flange goes on is slightly bigger than the one that the yoke goes on. You can put a flange on an older case in a pinch, but you cant put a yoke on a newer case. It is a very small differnce. The problem with putting a flange on the older case is there is a little play there. I did it and ran it for about 1000 miles till I rebuilt my original case. The flange style is better IMHO because it's much eazier to work on. The thing I dont understand is you said that you have a driveshaft from a AOD that is the correct length for an E40D. They are not the same length. The shaft for the E40D is much shorter.

 

No, what I said was I have a shaft from an AOD which is the correct length, because 4R70W = AOD. The E4OD shaft is too short. The AOD shaft takes the yoke but my '91 xfer case has the flange and I cannot put the flange from my E4OD shaft on the AOD shaft because the cardan joints are not compatible.

In any case, you answered my question, I can't just put a yoke on my BW1356, right?

 

measure up what you need length wise and go to the wrecking yard and see what you can find. an f150 or f250 might have a rear shaft that will work for ya. otherwise get the e4od shaft lengthened.

 

I really think your best bet is going to get the E4OD shaft lengthened. Even if you figure out what exact shaft you need and what Broncos (I doubt any F-series shaft will be the right length) it came in, you're going to look long and hard for one because most wrecking yards destroy them moving vehicles around.

 

I happen to have a T-case with the yoke. I rebuilt it. (new plastic inserts in the shift forks) I would be willing to trade you for your flange T-case. Or sell you it for $100. I see you are in Austin. I'm in Florida, but I drive to Houma, La every month for two weeks. (work) I could bring it that far. If you want it, I leave tomarrow. I even have some friends at work that live in Austin that might bring it there. But I would have to check with them. I couldnt arrange it this trip. Let me know.

 

interesting thought, but why are you putting a 4.6 into a bronco anyway? bored?

 

The output shaft in the BW1356 with the flange is .020" bigger than the same transfer case that is set up for the yoke-to-yoke output to the rear drive shaft as helirich explained. You can go to the trouble of swapping output shafts if you can find one but then it would make more sense to just swap t-cases.

I agree with termyt100, what's the urge to drop a 4.6 into a Bronco?

 

I used to have a 2000 Expedition with the 5.4L and it got 16.5 MPG and pulled like a freight train. Now I know the Expy weighs about 1000 lbs. more than the Bronco, so I got to wondering what a Triton could do in a lighter vehicle. I really wanted a 5.4L but I got the whole donor truck for $600 with 55K original miles on it (rollover) so the price was right for the 4.6L. Just something fun to try out. If it works out I will try a 5.4L in my F150, although it might be a tight fit due to taller deck height.

 

'Nuff said. Keep us in the loop as to how it turns out. Considering that a 4.6 would be the second-smallest (displacement) engine I've ever heard of in a Bronco... The smallest being the 170 (2.8L) I6 that came in the originals... I'm curious to hear what kind of performance/mileage you get out of it.

 

Thanks for the offer but the I can't use the yoke driveshaft because the tangs that hold the u-joint in are broken off. I will just have to have my flange driveshaft lengthened, I guess. How much does something like that cost?

 

Should be pretty reasonable, there are only a few tools involved and it's not a difficult job. If you bring in a piece of scrap driveshaft they can use to lengthen it might save you a few bucks.

 

I took both shafts to Austin Drivetrain at lunch and they said it would be easier and cheaper to cut the flange-style cardan joint assy. off the old shaft and weld it to the AOD shaft in place of the yoke-style assy., so that's what I'm having them do.

 

Yeah that would be a lot easier. How much did they charge you out of curiosity?

 

$125 plus tax.