Trans f/s prog... Wait, not quite
 

Got a call from my better half yesterday claiming that her X was making grinding metalic noises and shuddering before she pulled off the road. The message in her instrument cluster read "Transmission failsafe prog"

So while she got towed I researched but without being near the rig, it was just to prepare me for the possible mess on our hands.

Our indy (friend who helped us on her truck before and basically did my engine swap in the wagon) told me that the driveshaft to the front diff was bad and needs replacement. Said the teeth on the end were worn to far to grab the gear and that I should look for another shaft.

I'm curious to open up the diff and see if that gear should also be replaced and wondering if anyone has a suggestion for where to get that shaft or a good aftermarket replacement that doesn't break the bank.

Well, 3 months without an issue, I knew it would happen soon. Now she really wants to sell it. I'm trying to see if insurance will total the car and I can keep the engine, it's practically new. Argh BMW!!!

Actually pretty common, never experienced it but crops up enough for me to be familiar with it already lol!

There are extended drive shafts out for just this reason and a few DIY and documented repairs here and all over the forums.

IIRC it comes about from an AC evaporator drain that drips right on that area and it rusts out.

A proper fix I think would be to service both the diff and replace the shaft but a lot just use the longer shaft and it seems to work.

Here's a video on the driveshaft problem, and the repair. In addition to driveshaft, you may have to replace the spline hub in the transfer case.

https://www.youtube.com/watch?v=yeF0X3v6cj8

There's a guy on eBay that will sell you a modified driveshaft if you ship him your driveshaft or can sell you the replacement spline and you can weld it yourself or take it to a shop to have it welded.

The front diff should be ok since it is attached to the driveshaft with a quibo, it's only the end that goes into the transfer case that has the splines. Tell the little women to stop doing burnouts with the 4.6is.

Thanks guys!
Yes, she uh, burnouts... Probably not me braff'n in the snow for a month straight. You're right, totally her fault.

LOL!

I'll get right on this. Seriously, thanks guys.

Oh, my bad, up is right and it is actually the t-case side and shaft that you will be working on, not the front diff.

Joshdub actually has a shaft for sale in the classifieds here but I think it's for the facelift and will not fit your truck.

And oh, yeah, less burnouts ;)

After looking at the 4.6is driveshaft for sale on eBay, like so many parts on a 4.6 X5 it is specially made for a 4.6. That what happens when you buy a car that is a limited production. You gotta pay if you want to play.

Seems we pay slightly more than we play but I hear what you're saying.

Again, muchas gracias amigos!

New shaft, longer splines. Done.