Guidance on replacing Differential Yokes

[beckel]

Hi Guys -

I am working on installing the powerpack in my 998 and an needing to swap out the Yokes on the differentials. I read through the TM's but it does not seem to apply if you are moving from one yoke type to another as I am doing with the conversion from a 3L80 to 4L80E and NP242 transfer case and associated driveshafts.

Can someone please guide me on the process of swapping the yokes? I have new crush collars but tightening the pinion nut back to the same location as the old one once I have installed the new yokes doesnt seem like it would work since the yokes are different.

Also, is a puller required to remove the old yoke or will it slide off once the nut and spacer are removed?

Any help is greatly appreciated!

Brian

 

[beckel]

Going to respond to my own post here for archival purposes...in case anyone else encounters this issue while doing a 4l80E conversion.

The process of swapping the yokes was actually a total breeze. Essentially, you count the exposed threads (the old yoke and new yoke are the exact same dimension at the spline) and simply mark the pinion and nut with a paint pen. Use an impact to drive off the nut, the yoke will then slip right off (no puller required).

Installation of the new yoke is straight forward. Light grease on the sealing surface and coat the inside splines of the yoke with RTV. Slide the yoke back on in the same orientation that the old one came off.

The only tricky part to doing this is to ensure you do not overtighten the nut. Doing so will change the pre-load on the diff and could really ruin your day. Tighten the nut down by hand using a 3/4 ratchet. It will be very obvious when the nut reaches the same point as originally installed as the force necessary to tighten it (crush the sleeve further) will increase dramatically. At this point your alignment marks on nut and spine should line up. Tighten just SLIGHTLY beyond that point and you are done.

 

[Action]

I believe the correct process is in the manuals.
you use a needle type torque wrench to see the reading before the flange starts to move. That is how tight it needs to be after reinstall, plus a very small increment, which is listed in the TM.
This is more sensitive than a tie rod end.