Dan the Gear Man® Tech Note 1:
To maximize dust seal life and prevent squeaks, apply a thin, uniform coat of a quality grease to the seal lip.
Dan the Gear Man® Tech Note 2:
These seals are a fairly light friction fit on your inner axle shaft. The only special tool you need to install these are your two thumbs to push them on. If you do not install your axle shaft right away, you may find the seal has "popped" off the shaft shoulder. This is normal. Just push it back in place and install the axle shaft. Once installed the seal will stay on the shaft.
Dan the Gear Man® Tech Note 3:
This type of Outboard Axle Shaft Seal has a fairly short life. Most of them will be worn out within 3 or 4 years. Since they are just an outer protective seal, a failed one does not pose any real problem, although it is of course better to have them functional.
Dan the Gear Man® Tech Note 4:
Not all 1988-1997 Ford F-350 axle shafts are made to take this seal. If the backside of your inner axle shaft yoke does not like like QU40487 or QU40526, you will NOT be able to use QU40243 Seal!
Dan the Gear Man Tech® Note 5:
For the Model Years 1988 to 1991, there is conflicting part number information between Dana and Ford parts lists for the 1988-1991 Ford F-350 Dana 60 Front Axle. In 1988, Dana shows a mid year model change with axle Bill of Material Number 610313 that effects the axle shafts. My Ford factory Parts Books do not show 610313 axle tag number until 1990 and they still show the parts to be the same as 1985 to early 1988 axles. I can't remember any F-350 that went through the shop that we found the Dana information to be wrong, but truthfully, unless we did not have the correct part in stock, we probably would not compare the Dana and Ford parts data.
Ford F-350 Dana 60 front axles had an inner axle yoke design change. Dana lists the new axle design as 1988 mid model year change but Ford does not show this change until 1992. If you are looking for an inner axle shaft dust seal or outer axle shaft to spindle seal for a 1988 to 1991 F-350, you need to verify the the back side of your axle shaft yoke looks like QU40487!
Dan the Gear Man® Publication Reference Note:
QU40243 is item 22 in the Shaft, Hub, Brake, and Steering Components Full Color Exploded View that is included in these 4x4 Tech Publications: TSB4644, TM4637, and TM4688.