Hello all,

I need to make repairs to my 1997 F350 4wd diesel rear driveline. I have short window of time in which to do the repairs. I am curious to know if there would be any harm done to the rear differential or axle if I didn't get the repair done in time and had to drive the truck around with 4wd engaged only using the front axle for propulsion (rear driveline removed).

What I am not clear on is if the rear driveline spinning the input flange of the differential disperses oil throughout the diff housing for needed lubrication.

TIA,
Blanes

 

The ring gear spinning through the oil is what keeps all the bearings lubricated which will happen as the tires and axles are still spinning. Your rear diff will be fine in that aspect, however your transfer case might not be too happy. Short distance light load probably wouldn't hurt.

 

As said, the rear axle will be fine.

However the transfer case probably has a slip yoke. If it does, removing the driveshaft will mean there's about a 2" hole in the back of the transfer case. IF you can plug that hole well enough to keel the lube in and small animals out, then your transfer case will be happy running in 4WD without a rear driveshaft. But that hole is going to be your problem.

If your transfer case has a fixed yoke (Broncos did, but F-series trucks of this vintage generally didn't), then you can disconnect the driveshaft at the U-joint and you're fine. But your truck should have a slip yoke.

 

Thanks for the replies guys. You are bringing up things I did not consider.

Regarding the slip yoke possibility, my driveline has a rubber accordion boot on it, wouldn't that mean the driveline has a slip joint rather than where it connects into the transfer case? I also just checked the rear of the transfer case and there is a flange coming out of it and where it meets the transfer case is clean as a whistle. Wouldn't that be greasy or have some kind of rubber boot if it where a slip yoke?

Often times, when getting parts, I am told that Ford didn't make an 1997 OBS truck. Even look at this forum, it doesn't list 1997's in the title. Through the years I have found a few odd things as if this truck is part OBS and part Super Duty.

Thanks again,
Blanes

 

Never seen a transfer case with a slide on yoke.........I think they all are solid mount yokes.....

 

I checked my truck (the one in my sig line) and sure enough, it had a flanged output. That truck is 99.99% original, btw.

Cheers!

 

The Super Dutys didn't come out until 1999. The F-250 & 350 (heavy duty) was around until '98. Long after the F-150 was redesigned.

 

92-95 had slip yokes on the 1356 (unless cab-n-chassis)
96/97 had the flange

 

Thanks for all the help and the information guys.

For the record:

The Universal joint that fit my 1997 F350 4WD automatic diesel is Spicer 5-178X. The one in the computer at Oreilly's was the wrong one.

The transfer case has a flanged output as noted by Diesel-Brad.

The u-joints that were on the rear driveline were not serviceable (original?). The ones I installed are. Unfortunately no matter how you place the zerks they are not accessible while the driveline is installed. To grease them I had to disconnect the front of the driveline in order to swing the driveline far enough sideways to reach the rear zerk. You can't disconnect the rear ujoint to grease it since the caps are held on by the brackets that hold it to the input flange of the rear differential. Trying to grease the rear while it is disconnected will just push off the caps.

Does anybody know what the strange bolts heads are on transfer case rear flange? Since two of them had backed out 1/8" another one 1/16", and the fourth one was not tight I was able to get them off using a 13mm hex head socket. Putting them back on though a buggered up the heads getting them tight. When I regrease the joints I plan to replace the bolts with standard hex heads.

Thanks again,
Blanes

 

I think they are 13mm 12 point. Most box end wrenches and 12 point sockets will fit them (12 point sockets are "normal" sockets that will fit onto hex heads in 30 degree steps rather than 60 degree steps like a 6 point socket)

 

My truck has 12mm 12point head bolts on the rear driveshaft pinion flange.

I believe the fixed output vs slip yoke setup has to do with HD vs F150 as well. My 96 F150 SCSB has a slip yoke, but every HD 96/97 I've seen has fixed output. Not terribly relevant for the OP, but a future reader may appreciate the clarification.