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Discussion Starter #1
So for example my bronco has 3.54 gears front/rear ( not sure of transfer case ratio I cannot find the tag, its bw1356). Does changing the transfer case with a different ratio affect the gearing at the rear end when in 2wd or when in 4wd to the point of breaking ujoints.

Hopefully this makes sense. Thank you.
 

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The Tennessee Warden
96 XL, 5.8L, E4OD, BW1356, 4.56 gears
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So for example my bronco has 3.54 gears front/rear ( not sure of transfer case ratio I cannot find the tag, its bw1356). Does changing the transfer case with a different ratio affect the gearing at the rear end when in 2wd or when in 4wd to the point of breaking ujoints.

Hopefully this makes sense. Thank you.
No, if your bronco has 3.54 in front, it has 3.55 in the rear. The BW 1356 has a high range ratio of 1:1 and a low range ratio of 2.69:1. This ratio does not change your rear or front gear ratios at all. If you change to a different TC with a different low range ratio, it’ll just change that, the low range ratio. It’ll either be lower or higher, but won’t affect anything during normal driving in 2 high (or 4 high for that matter).
 

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Discussion Starter #3
Thank you very much, I'm swapping in a 4 sp manual from an 86 f150 and was just wondering as the tcase is a np208 which is fine as the truck just see's dirt roads fishing/hunting but the ratio i was questioning but sounds like it should be fine?

Thanks
 

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The Tennessee Warden
96 XL, 5.8L, E4OD, BW1356, 4.56 gears
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Thank you very much, I'm swapping in a 4 sp manual from an 86 f150 and was just wondering as the tcase is a np208 which is fine as the truck just see's dirt roads fishing/hunting but the ratio i was questioning but sounds like it should be fine?

Thanks
Yeah, it’ll be fine as far as I can tell. The only thing I’m not sure of would be the trans mount and driveshaft length, if they’re different.
 

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Discussion Starter #5
That I can comment on. The rear shaft has to be replaced completely as the (cardon joint?) Is not compatible with the output shaft in rear. Front shaft is bolt on compatible, trans mount from bronco is exact fit and does not need modifications or relocation. Gear box is directly a fit to the 5.0.

I just completed the swap this afternoon and so far so good.

Thank you very much! I'd buy you a beer if you where local lol.
 

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The Tennessee Warden
96 XL, 5.8L, E4OD, BW1356, 4.56 gears
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NP man - So does that np208 have a slip yoke in the back of it instead of a flange yoke? Is the driveshaft going to be a two u joint type with no double cardan? If you go that route you may have vibration issues because you’re going to have more angle at the front u joint than the rear u joint. With that kind of dshaft, each angle at the u joints needs to be the same. I’d try to find a different tailpiece for the TC and use a double cardan dshaft, but you may be able to get away with a slip yoke tailpiece and the right shims for the leaf spring perches so you can match the angle near the TC.
 

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Discussion Starter #7
Yeah it's a slip on style yolk. I was going to have truck towed to a driveline shop to have a shaft created and knowing what I do now seems that I'll need to change the yolk but that poses a large question of what style yolk now that its only a slip on style? So would I be looking for a double cardan slip on yolk for np208?
 

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Discussion Starter #8
Also not sure if the vibration would come from suspension lift? I'm stock height if that makes any difference in eliminating the cardan?
 

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The Tennessee Warden
96 XL, 5.8L, E4OD, BW1356, 4.56 gears
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The thing is, and the reason broncos have a double cardan joint, it’s a short wheelbase, which causes a higher angle coming from the TC toward the rear end. At a high angle, a single u joint causes the driveshaft to turn non-uniformly, so the DC uses two u joints, so that the second one cancels the oscillation from the first. That is also why the u joint at the rear axle is almost straight on with the pinion - so it won’t reintroduce an oscillation. Most RWD cars and pickups use a d shaft with two separate single u joints, one front and one rear, because the angles aren’t extreme. The Bronco has higher angles.

You should look into a slip yoke eliminator (if one exists) for the NP208 or replacing the TC tailpiece to eliminate the slip yoke and go with a flange yoke so you can install a DC driveshaft. That will probably be your best bet to avoid vibration problems. The driveline shop may have other ideas for you though.
 

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Discussion Starter #10
Thanks for the information on the drivelines. Very good 👍. Found a few kits that either require cutting the shaft and or providing a new shortened shaft. Also thinking that if the 1356 will bolt to the back of the gearbox I might just separate the np208 and swap the 1356 back and retain stock setup. More to this then i expected 😂.
 

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Discussion Starter #12
After reading a post it looks like my old bw will bolt up to the 4sp. Linkages might need some adjustments but thats much easier then trying to make the 208 work. Then I'll retain the stock dcard and just have rear shaft cut to fit. A little more flatback work and I can move on.

 
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