P71 tailhousing and MMC driveshaft in my box...

[Mercracer]

Since the advice for using the P71 tailhousing and aluminum driveshaft on a whale is to go ahead and use it with the the factory short tailshaft 4R70W, I have concluded that I can do the same on an AOD in a box. The driveshaft length of the 97+ aluminum and MMC driveshafts looks at a quick glance to be the same as a 90-91 GM with an aluminum driveshaft. (I was wrong.. see below)
I am going to go a step further. I am going to take a 89-93 2wd Truck AOD which has the long tailhousing and 7 spline speedo gear and use it in my box with the substitution of the P71 4R70W tailhousing.
Obviously I am going to measure and mock it up before I would try running it this way.

[Mercracer]

I took another look at the driveshafts I have and I believe that the Box driveshaft is longer than the 97 P71 driveshaft (95-97) and the MMC driveshaft with the 97 being the shortest. I am going to more accurately measure all 3 and post actual numbers tomorrow.

[Mercracer]

I can tell you that all '90 through '02 and likely later CV/GM vehicles use the same axle pinion flange regardless of the application. The only large U-joint aluminum driveshafts were '95 and newer P71 application. The 90-92 aluminum driveshafts were small U-joint (1310). The vibration dampener slip yoke on aluminum driveshafts looks like a 1992 application only. Both 5.0 and 5.8 P72 vehicles used steel driveshafts with large U-joints (1330).

[Brown_Muscle]

interesting....let us know how it goes!

[P72Ford]

Ed.

My '87 has a '97 P71 shaft, and combination u joints.

I am slightly confused by the above posts.

Does this seem feasible? Not that I am confused, but that I have a '97 shaft in the car? You are saying that the '97 shaft is shorter than the box shafts, which is making me wonder.

[Mercracer]

Ed.

My '87 has a '97 P71 shaft, and combination u joints.

I am slightly confused by the above posts.

Does this seem feasible? Not that I am confused, but that I have a '97 shaft in the car? You are saying that the '97 shaft is shorter than the box shafts, which is making me wonder.

The only box shaft I have at my house is the aluminum one. The '97 P71 shaft definitely looks shorter. The ~1" shorter is likely not a huge deal so long as the slip yoke is seated in the tranny sufficiently and the car is not turning very high speeds or launching with slicks and a pile of torque.
Have you inspected your tranny tailhousing bushing for excessive wear lately?

[P72Ford]

The only box shaft I have at my house is the aluminum one. The '97 P71 shaft definitely looks shorter. The ~1" shorter is likely not a huge deal so long as the slip yoke is seated in the tranny sufficiently and the car is not turning very high speeds or launching with slicks and a pile of torque.
Have you inspected your tranny tailhousing bushing for excessive wear lately?

I'll have to look into this. The car allegedly suffers from a highway vibration (haven't had it on the highway yet).

I'll have to check mine against a steel shaft I have. If I notice a significant difference, I'll swap the shaft for a steel one (with new joints).

I plan on launching on drag radials...

[85crownHPP]

I only felt it vibrate over 120mph or so...

[gadget73]

I would expect the driveshafts on a 4R70w car to be ~1 inch shorter since the 4R70w as used in the Panther is about that much longer than the AOD. Shouldn't be a problem though I wouldn't think. A spacer at the pinion flange to take up the difference should be easy enough to do if thats a concern. I think they actually make them for Mustangs.

[Lincolnmania]

that 97 aluminum shaft was the same length as the 87 shaft

[P72Ford]

Thanks, Scott.

I may have the shaft checked for balance, to see if that is the issue. I want to feel it before I do anything, though.

[Heretic]

Ed, the 4R70W is 7/8" longer than the AOD. If yours works I'm gonna take that route and get the appropriate year aluminum shaft. My steel DS will physically bolt in to my 85 with the 4R trans, but it has hardly any play at all, and with suspension travel I suspect it would bottom out.

[Mercracer]

I measured a steel 97 shaft and it was 55.5" ctr to ctr U-joints.

[Mercracer]

I layed down all 3 aluminum shafts I currently have on a level surface and measured them. The 90/91 is the longest at 55 3/4", the 2000 MMC is next at the 55 1/2" everyone is quoting and the 97 is the shortest at 55 1/4" long. I still need to get a measurement on the 92 4.6 AOD aluminum driveshaft. The ground should be frozen on Tuesday when I get back to the bone yard. It was a giant flowing river/lake and mud puddle on Thursday. I will not get to my 91 P72 driveshaft for a while.
I have not picked up a long tailshaft AOD yet either but I have located a couple in the local yards.

[Heretic]

How long is the stock steel driveshaft on the AOD 80-87 boxes? I am considering a MMC upgrade for my 85 w/4R70W thanks to this thread. Apologies for the slight threadjack, Merc.