New DS, yokes and preload

[NJKURPat]

So since I'll need 4wd soon I can't put off getting a new front ds. Going the double cardan route. In order to do this I need to replace my pinion and tcase yoke.

All the standard write ups just have you re torque the pinion nut with a write up mentioning a more proper practice in the beginning: "Please be aware that there is actually a very specific method to replacing the pinion yoke on your front axle and it can be found in a Factory Service Manual. However, this method requires that you use a fine inch lb. torque wrench capable of being set to an inch. A torque wrench of this accuracy is not something you can pick up at your local parts or hardware store and if you can find one, it will be very expensive. Needless to say, I will not be focusing this write-up on that method but rather, show you what you can do with what you got."

This is what I have found from the service manuals:
(Torque to rotate should have been measured and recorded, before pinion nut removal.)

5. Install pinion washer and a new nut on the pinion gear.
6. Hold pinion flange (1) with Spanner Wrench 6958 (2) and tighten pinion nut to 217 N·m (160 ft. lbs.).
7. Measure pinion torque to rotate (1) inch pound torque wrench (2). Pinion torque to rotate is recorded reading plus 0.56 N·m (5 in. lbs.).
8. If pinion rotating torque is low. Hold pinion flange with Spanner Wrench 6958 and tighten pinion nut in 6.8 N·m (5 ft. lbs.) increments until pinion torque to rotating is achieved.
CAUTION: If maximum tightening torque of 271 N·m (200 ft. lbs.) is reached before torque to rotate is achieved, the collapsible spacer may have been damaged. Never loosen pinion gear nut to decrease pinion gear bearing rotating torque and never exceed specified preload torque. Failure to follow these instruction may result in damage.
9. Install propeller shaft.
10. Install brake components.
Both front and rear Dana 44 axles, the max torque is 200 ft/lbs. Dana 30 is 400 ft/lbs.



So input on just following generic instructions and torquing to spec, marking the nut position, or doing a full preload check.

[BadAssEddie]

The rotational load checked beforehand is just a baseline to compare to afterwards. There is no way to determine the bearing preload without measuring the axial travel of the pinion which correlates to the preload of the bearingset. The reason "preload" is checked with just the pinion installed during a gear setup is because it is the best way to compare a torque linearly to a preload and has the least amount of variables and rotating mass involved. Your gearset has already been setup once, so this process of adjusting the preload with shims or similar and then measuring the restive torque is set, i.e. it won't change because you are not changing preload by moving the bearing into or out of interference with the race. Once you re torque the pinion nut after yoke install, it will achieve the same preload as before. You check the "rolling" torque before as a sanity check to be completed after the yoke swap. The pinion nut has a torque specification, just like any other fastener on the vehicle, you physically move the bearing to acheive the desired preload, the best way to check this is torque, not axial distance, even though only a tertiary means. That is why that magic number is 160 ft-lbs like we were talking about before.

Hope that makes sense. Just do it like the instructions say, torque to as close as 160 ft-lbs as possible and get to as close to the initial measurement as possible. I don't think you will have a problem.

[NJKURPat]

Probably going to mark the thread count, and nut position as a reference then torque to spec.

[BadAssEddie]

Probably going to mark the thread count, and nut position as a reference then torque to spec.

That's actually a better method for torque to clamping force verification, just make sure you are comparing apples to apples, as in the old flange and new yoke have same spline engagement and the nut shoulder is the same relative to location from end of pinion shaft, otherwise you won't have the same preload. For comparison, the difference in endplay to heavy preload on a bearing set is less than 0.004" often times, which is the same thickness as a sheet of paper. You will only be able to be so accurate, just try your best to be consistent and accurate.

Edit: Timken and SKF have fairly different life ratings and designations but this is a good visual of how preload vs endplay works out. The more you torque the pinion nut the further to the right your pinion bearings are, use 160 ft lbs as the zero mark.

[NJKURPat]

Any suggestions if the yokes have different thread engagement? Just trying to bounce around ideas at the moment.

[redneckrapunzel]

just regear to 5.40s since you have to reset your preload either way. problem solved.

[NJKURPat]

Might as well just swap in a 60....

[FJCcrawler]

Fuck it, tight's tight. Preload is just imaginary bullshit.