Changing supercrew driveline to 2-piece.

[lump-dog]

I have a 2wd 2002 f150 supercrew, deavers, automatic, and I had a 2-piece driveline made (to replace the stock aluminum 1-piece). I questioned the driveline builder about having a slip yoke at the tranny and a slip-yoke between the 2 driveline pieces. He said no problem, some new trucks have this same configuration. Every 2-piece driveline I've ever seen had a fixed yoke at the tranny and the only slip was between the 2 drivelines. The stub and yoke splines in my new driveline was so tight it would rather slide at the tranny, so it pulled the front driveline back into the carrier bearing, to the extent that it burned up the rubber and actually worked it's way into the carrier bearing housing in about 10 miles of driving. Luckily there was enough yoke left in the tranny that it didn't do any major damage, only casualty was the carrier bearing. The temporary fix was to dress the splines between the 2 drivelines so that they would easily slide. I basically had to remove the glide coat, and some material, and now have what I would consider to be similar to a worn out slip yoke and stub. It works fine now, it no longer slides at the tranny, but I'm concerned with the correctness and longevity of my setup. Cant' get a straight answer from anyone in my area. Any input?

[FABRICATOR]

You should only need a slip yoke in the rear drive line, between the diff and the center support bearing. Unless things are especially flexible, you should not need one between the transmission and the center support bearing. Even when new, the driveline slip yoke should not need more than perhaps 10-15 pounds, or so, of push to make it move. Removing the glide coat is not good at all. It is not clear who had input on what, but any competent drive line shop should be able to make it proper.

[1450-ranger]

Get a fixed yoke at the trans or you will continualy burn up carrier bearings. The whole driveline will shimmy back and forth on the carrier bearing and wear it out. Sometimes they will last 200 miles, sometimes 5 with the set up you have.

[DWymoreB]

We do drivelines here at the shop, and I get people (kids mostly) coming in all the time with torn up long single piece alum DLs. The proper fix of course is 2-piece steel. I had one guy yank the DL out of a 19?? F250 and it almost bolted in. Somehow he ended up set up the same way though. I told him he needed to go fixed on the trans end, but instead he brought some racing centerbrg that was poly and had some kind of retainer to keep things where they should be. My memory is a little fuzzy on details, that's about all I remember. It really should only have one slip, but it's something to think about.

[Jess@HighAngle]

What happend it called carrier brg drift- Now if you use a reinforced carrier and steel shell its less likely an issue- But if it was mine- a fixed trans side would be what i'd do first -Jess

[DWymoreB]

Thanks, guru. :)

[DWymoreB]

Another note is that it is preferable to put a fixed yoke on the trans and first section right after the carrier brg and put the slipyoke on the second section. That way, as the suspension cycles it is plunging the splines in and out directly in a straight line instead of slightly sideloading the splines and causing bind and excess friction. This may have been part of the cause of your problem if it was set up that way. Factory trucks are often set up that way and work fine with minimum angles and travel as long as they're greased well. Add angles, travel, speed, and a little lack of grease and you tear things up.

EDIT: Also, sometimes the splines are set so that they only go on one way, but sometimes even if they aren't, it only slides well one way.