Driveshaft swap

[Kaysboat]

I'm thinking about doing a drive shaft swap on the 99 Grand Marquis, and replacing the stock steel shaft with an aluminum Police shaft. I had a couple of questions:

1) I've read you have to replace the tail shaft aswell. I'm assuming that's the part that bolts onto the differential and houses the rear U joints right?

2) Is there an easier way to balance the shaft other than the trial and error and hose clamp method as outlined in the shop manual? Can you get an aluminum drive shaft balanced at a shop like a steel one, and install it any way you want?

3) Is it even worth messing around with? (That's the big question).

Thanks.

[93 Marquis]

I did it in my '93 Marquis.

1) It's the tail-housing, not the tail-shaft that you want to swap. The output shaft is the same length and spline on both the PI and non-PI cars. The housing, however, is longer. In my case, I didn't use the longer housing and didn't have any problems.

2) I just put mine in and had no issues with vibration. If you want to have the balance checked, call driveline shops in your area. Aluminum parts aren't as rare as they used to be, so most places should be able to handle it.

3) Personal preference. In my Marquis I can tell you there wasn't really a noticeable difference between the steel and aluminum driveshafts. If you need to replace it anyway, go for it. If you want the higher speed capability, go for it. Otherwise you won't even know it's there.

Ray

[torquelover]

Do you plan on going with a different RAR soon? Are you thinking about going plaid?

3) Personal preference. In my Marquis I can tell you there wasn't really a noticeable difference between the steel and aluminum driveshafts.

Results do vary, especially if your steel DS is bent. On my old P72 the car had better throttle response off the line and at low speeds, and it even rode better, too. The old DS was bent and caused severe vibration with the 3.27 RAR. At 130, the car resonated so badly, the interior dome light lens fell off and left the vehicle (windows down). After the Al DS it was smooth sailing up to about the same speed, and then a light vibe afterwards. In comparison, switching to an Al DS in my Fox and a few others saw no difference whatsoever.

I got my Al DS from a local driveline shop. It spun true without needing any balancing, whereas the old steel DS was not repairable. If you found an Al or MMX DS and it needed balancing, I'd look for another one.