Dana 50 TTB coil conversion from Bronco Graveyard

[Ford F834]

https://shop.broncograveyard.com/mobile/80-97-F250-Stage-1-D50-TTB-Front-Leaf-Spring-Delete-Kit/productinfo/337800/

[Gary Lewis]

I like it, except for three things:

• $2855!?!?!? Granted it should ride better, in theory, than a D60 with SD springs, but that combo will come in closer to $2k. And, it is a bit stronger.

• No bushings: The Sky kit is available with Heim joints, and when I asked Erik about that he said it is "For those who just have to have them". But, he went on to say that the ride will suffer and there will be more vibration. So he didn't recommend them. And this kit has no bushings at all that I can see, as opposed to the bushings in the spring eyes and shackles that the D60 Sky kit has.

• D50: Do they also have it for a D44HD? My limited understanding is that the D50 was in the Supercabs and Crewcabs above 8500 GVWR, or in a regular cab over an even higher GVWR. But the vast majority of the F250's I've seen have had the D44HD.

I've come to the conclusion that if I were in the market for a 4wd F250 I'd buy an '85 or '86 F350 instead.

[85lebaront2]

Now, if something like that for a live axle, I might (if I completely lost all vestiges of common sense) think about doing a 4WD conversion on Darth, probably with a divorced transfer case like the military trucks used.

[Gary Lewis]

Now, if something like that for a live axle, I might (if I completely lost all vestiges of common sense) think about doing a 4WD conversion on Darth, probably with a divorced transfer case like the military trucks used.

Why a divorced t-case?

[Ford F834]

I like it, except for three things:

• $2855!?!?!? Granted it should ride better, in theory, than a D60 with SD springs, but that combo will come in closer to $2k. And, it is a bit stronger.

• No bushings: The Sky kit is available with Heim joints, and when I asked Erik about that he said it is "For those who just have to have them". But, he went on to say that the ride will suffer and there will be more vibration. So he didn't recommend them. And this kit has no bushings at all that I can see, as opposed to the bushings in the spring eyes and shackles that the D60 Sky kit has.

• D50: Do they also have it for a D44HD? My limited understanding is that the D50 was in the Supercabs and Crewcabs above 8500 GVWR, or in a regular cab over an even higher GVWR. But the vast majority of the F250's I've seen have had the D44HD.

I've come to the conclusion that if I were in the market for a 4wd F250 I'd buy an '85 or '86 F350 instead.

Gary, I agree that the price is pretty steep. It does include a $350 core for the axle, I believe, but then there is freight on that sucker both directions. It would be interesting to hear a comparison of the ride quality vs. a SAS with SD springs. The one advantage I can think of would be greater travel and articulation. I don’t see why they couldn’t do a D44HD, but my guess is they might have you modify your own axle and return it to you. I think the assumption is that if you go to all the trouble of converting to coils you would want to upgrade to D50 if it didn’t have that already. Seems to me this product was designed for 4x4 enthusiasts who really prefer IFS over a straight axle but want more beef than 1/2 ton stuff. There was a guy on Facebook that claimed to have made his own for around $800 in parts, but obviously you have to be good at fabrication:

[Gary Lewis]

Gary, I agree that the price is pretty steep. It does include a $350 core for the axle, I believe, but then there is freight on that sucker both directions. It would be interesting to hear a comparison of the ride quality vs. a SAS with SD springs. The one advantage I can think of would be greater travel and articulation. I don’t see why they couldn’t do a D44HD, but my guess is they might have you modify your own axle and return it to you. I think the assumption is that if you go to all the trouble of converting to coils you would want to upgrade to D50 if it didn’t have that already. Seems to me this product was designed for 4x4 enthusiasts who really prefer IFS over a straight axle but want more beef than 1/2 ton stuff. There was a guy on Facebook that claimed to have made his own for around $800 in parts, but obviously you have to be good at fabrication:

I understand the desire to upgrade from the D44HD. The difference in the u-joint sizes between that and the D60 is significant, and I assume the D50's joints are bigger than the 44's. And the axle shafts themselves are bigger. But while I think the advantages of the TTB's ride and articulation would be appreciated, wouldn't you still have the reduced turning radius as opposed to SAS?

As for cost, one thing I didn't think about in this is the cost of the D50 front end itself. If you have a truck with a D44HD then you'd have to add the cost of the D50 components to the $2,855 in order to get a fair comparison to the $2,000 for the D60.

But Clayton Paul's conversion is interesting as it could be done for either a D44HD or a D50. I think. I don't know what he had to do about shock mounting, but it is really a pretty straight forward conversion. However, I don't like the way he mounted the end of the radius arm to the frame. Ford says not to weld to the flange of the frame as it weakens it. And all of their mounts are fastened to the web as well as the flange. So I wouldn't do it as he did. But otherwise it looks good.

 

[Nothing Special]

Why a divorced t-case?

I don't know Bill's specific reason, but generally the "benefit" to divorced transfer cases is that they use a 2WD transmission. I put "benefit" in quotes because it really isn't a benefit if you are sourcing a new trans anyway (just get a 4WD trans to start with). But it is a plus if you have a lot into your current 2WD trans and want to keep it.

As to the coil spring TTB Dana 50 being worth 3 grand, it sure isn't to me. But for people who want a prerunner-style suspension that can go fast in the desert, coil spring TTB is about the best you can do in a 4WD. And for that type of use compliant bushings are undesirable. People who are pushing those boundaries are very willing to give up some vibration and harshness for the precision and ruggedness of heim joints.

[Gary Lewis]

Why a divorced t-case?

I don't know Bill's specific reason, but generally the "benefit" to divorced transfer cases is that they use a 2WD transmission. I put "benefit" in quotes because it really isn't a benefit if you are sourcing a new trans anyway (just get a 4WD trans to start with). But it is a plus if you have a lot into your current 2WD trans and want to keep it.

As to the coil spring TTB Dana 50 being worth 3 grand, it sure isn't to me. But for people who want a prerunner-style suspension that can go fast in the desert, coil spring TTB is about the best you can do in a 4WD. And for that type of use compliant bushings are undesirable. People who are pushing those boundaries are very willing to give up some vibration and harshness for the precision and ruggedness of heim joints.

So a number of the Jeeps seen in those videos are probably running Heim joints? Many of them look to have pretty serious suspension systems.

[Nothing Special]

So a number of the Jeeps seen in those videos are probably running Heim joints? Many of them look to have pretty serious suspension systems.

The most serious dedicated rock buggies do. While coil sprung (coilover actually) TTB is about the best there is for 4WD prerunner suspension, in rock crawling the ultimate setup is a "link" suspension with heim joints and coilovers. Links with heims give very free articulation and the possibility of gobs of travel with no axle-wrap (axle wrap can (figuratively at least) kill you in the rocks when you are getting on the gas in low-low with 100:1 torque multiplication). And coilovers let you realize the possibility of gobs of travel. The down-side is more harshness due to the lack of any compliant bushings. For that reason some street/rock vehicles will run urethane bushings, or "Johnnie Joints", a sort of hybrid urethane bushed spherical ball joint (developed by John Currie), giving most of the off-road benefit of links and heims while not giving up all of the harshness-dampening qualities of factory rubber bushings. A lot of the Jeeps in the videos we've been looking at in my trip report thread are probably somewhat street oriented, so I wouldn't be surprised if they have some bushings somewhere. But yes, they are pretty serious!

[85lebaront2]

Why a divorced t-case?

I don't know Bill's specific reason, but generally the "benefit" to divorced transfer cases is that they use a 2WD transmission. I put "benefit" in quotes because it really isn't a benefit if you are sourcing a new trans anyway (just get a 4WD trans to start with). But it is a plus if you have a lot into your current 2WD trans and want to keep it.

As to the coil spring TTB Dana 50 being worth 3 grand, it sure isn't to me. But for people who want a prerunner-style suspension that can go fast in the desert, coil spring TTB is about the best you can do in a 4WD. And for that type of use compliant bushings are undesirable. People who are pushing those boundaries are very willing to give up some vibration and harshness for the precision and ruggedness of heim joints.

The other benefit from my standpoint would be driveshaft length. My current rear shaft is two piece, one is about 3' long, the other is probably about 6' long. There is a center support on the crossmember that carries the bearing. If I were to rebuild my E4OD and add the transfer case and adapter, well, Gary can measure the overall length. You end up with a very short connecting shaft or a rather long rear drive shaft (remember Darth is a crew cab so is 35" longer than a standard cab long bed). My though was like the USMC trucks I used to drive and work on. Other than the M38 and M151, they all had divorced transfer cases. If I were to install a divorced transfer case where the rear shaft area coincided with the existing center support bearing, or maybe a little forward I lose the off center weight on the rear of my transmission, lessening the chance of breaking the adapter, I gain a longer front drive shaft which will tolerate more suspension travel. The only concern would be possibly having to make a modified transmission crossmember to allow the front drive shaft plenty of room.

Best option, find a late enough rolled Super Duty 4WD dually and get all the running gear less the powertrain from it, that way I would also have the late 4 wheel disk brakes. These trucks use a Dana 60 live axle with radius arms and coil springs.

Gary, just an interesting observation, looking at the front suspension information on Matt's 2002 Excursion, the spring setup looks an awful lot like the kit you installed on BB.