Looking for help and advise before starting project.



2000 F550 Crewcab 200" WB 7.3l Diesel 2wd Automatic



Recently at 260K miles I had a complete loss of forward gears while still having the reverse gear. From my research this is a catastrophic failure requiring a full rebuild on the transmission. I would love

to undertake a manual trans swap but I don't have the time and energy to get it done in the budget and time I have to dedicate. I am seeking advice on parts needed and problems I might run into swapping

my 2wd automatic transmission for a 4wd auto. I need the low range for slow low gear climbing that likely toasted the original transmission.

Parts I need:

-4wd trans

-transfer case(hopefully manual engagement)

-driveshaft

-4wd trans mounting bracket?



Has anyone completed a project like this before on a long wheelbase model? I believe the mounting bracket, transfer case and transmission is universal across all super duty trucks. Does the whole driveshaft

need to be replaced or is it just the one section closest to the trans/tcase? I am planning on getting a remanned trans from monster transmission for the value and warrantee.



Any help and/or advice would be greatly appreciated.

 

The multi-piece driveline is balanced as an assembly, not as individual sections.

There is some science behind the length distributions of each section of a multi-piece driveline.

In your application, driveline balance is even more important, due to the higher shaft assembly rotational speeds from the 4.88 rear axle ratio of the F-550 rear end.

In production, the driveline assemblies are balanced at 3,000 rpm. A lot of driveline shops do not have the equipment to balance a multi-piece driveline at 3,000 rpm. The most common mom and pop driveline shop has the equipment to balance a simple driveshaft repair at 500 rpm. That's below idle speed, and no where near an RPM where the F-550 lives at 65 mph. (2,500 RPM).

So do make sure you find a capable and competent driveline shop when the time comes.

The other issue may be the output shaft/yoke from the transfer case. The F-550 uses larger U joints than the pickup trucks, even though the transfer cases between the pickups and the chassis cabs are otherwise the same.

I have the same year, cab, transmission, engine, and model of truck as you do, and personally, and I use 4LO all the time, without engaging the front hubs. Even if you didn't need a driven front axle, I can certainly understand your motivation for adding a granny low in the form of the 2.71:1 ratio that the NP-271/273 transfer case offers. This is most especially helpful in reverse, which is geared way too high in the 4R100.

ESOF (electronic shift on the fly) was not offered in the chassis cab in model year 2000, not even in the Lariat trim, which I have also. Instead, all 1999-2003 chassis cab 4WD transfer case implementations were MSOF (Manual Shift On the Floor), irrespective of trim level or transmission type.

 

Hi thanks for your reply.
you obviously have a good depth of knowledge on the subject. I have a 200” WB truck. Do you know if I can just swap on of the driveshaft components or do I need to find a whole new set? I am not aware if each wheel base had its own driveshaft length or if they overlapped in size some how. I think this is the big hurtle in my case…

 

The driveline assemblies differ between the 6.8L gas, the 7.3L diesel, the ZF6 speed manual transmission, the 4R100 automatic transmission, 4x2 vs 4x4, cab style (due to location of frame kick-up, which alters crossmember shape and angle at locations where a carrier bearing bracket would be mounted), and of course, wheelbase.

For some driveline parts, there are differences between F-450 chassis cabs and F-550 chassis cabs, due to the F-450 having a Dana 80 rear axle, versus the F-550 having a Dana 135 rear axle with a huge 14.25" ring gear, which results in a larger "pumpkin" and longer length carrier that occupies more of the driveline axis length... hence different parts.

Yet, some parts are the same. For example, the frame brackets that mount to the crossmembers to hold the center driveline bearings happen to be the same part number bracket between the 4x2 and 4x4 versions of your specific truck. Likewise applicable to 4x2 and 4x4 is the location of this bracket on the #4 crossmember (other wheel bases use the #3 crossmember).

The 3 piece driveline consists of a coupling shaft combined with a 2 piece driveshaft, along with the requisite slip yokes, center bearings, and end yokes to attach it all.

Your question is a essentially can you get away with simply replacing (or shortening the existing) coupling shaft in order to accommodate the transfer case you are adding to the rear driveline.

That sounds like a reasonable approach, because you are on your own anyway as far as parts are concerned. The part number for the coupling shaft that you have is F81Z-4817-xx, where xx is a place holder for the two letters that determine the difference between coupling shafts, per the specific application combination of options inventoried in the first paragraph of this response.

Unfortunately, I do not know what the specific suffix is for a a 2000 F-550 Crew Cab 4x4 200" WB... otherwise I could have saved typing the sentence above and just given you the complete part number. You will have to prevail upon a Ford parts dealer for that information, or some online Ford parts seller. Prepare to be disappointed, because I have checked the Ford parts information that I still have from 20 years ago, and while I could find the suffix for the Regular Cab 200.8" (aka 201") WB (has longer CA), I could not find the suffix for the Crew Cab 200.2" WB that you have. Sorry.

I ordered a 2003 F-550 crew cab chassis cab 4x2 with the 200.2" WB brand new in 2002, to get the order in for a 7.3L before production switched to the 6.0L, so I am familiar with the beast that you are dealing with presently, although I never converted it to 4x4. The truck was simply used as it came vocationally until the State required that it be sold (otherwise it would still be in use). This is in addition to the 2000 F-550 crew cab chassis cab personal pickup truck that I still have, which was ordered wtih 4x4 from the factory, but is only 176" WB with a 2 piece driveline, not 200.2" WB.

Good luck with your project. Consider shooting and posting some photos of your progress along the way, as I am sure others will be interested in your conversion.