Driveshaft?

[vmaxmarauder]

I would like some input on the MMs drive shaft from what ive read if you have
stage 1 mods the weak link is the drive shaft. Would a PI drive shaft - XW7Z-4602-AA be an upgrade or are they about the same? If it is a better what is a fair price. thank you.

[fastblackmerc]

Use the search function. There has been extensive discussion on driveshafts.

[vmaxmarauder]

Drive shafts (http://www.mercurymarauder.net/forums/showthread.php?t=45068&highlight=driveshaft) (http://www.mercurymarauder.net/forums/images/misc/multipage.gif 1 (http://www.mercurymarauder.net/forums/showthread.php?t=45068&highlight=driveshaft) 2 (http://www.mercurymarauder.net/forums/showthread.php?t=45068&page=2&highlight=driveshaft) 3 (http://www.mercurymarauder.net/forums/showthread.php?t=45068&page=3&highlight=driveshaft))
burt ragio Still doesnt answer the question in the post. did you read what i wrote?

[RR|Suki]

what do you mean by weak point? Some people had issue at high speed with vibration. As far as a part that will break with "stage one" (whatever that means). I still have the stock driveshaft and it's fine.

[gdmjoe]

vmaxmarauder - Would a PI drive shaft - XW7Z-4602-AA be an upgrade or are they about the same?
That is the part # for the aluminum metal matrix driveshaft.

It would be an upgrade, however, it is no longer available from FoMoCo. You would need to find a used one out of a 2000 P71. *NOTE: Wasn't available prior to nor after that year. Standard issue that year only.


If it is a better what is a fair price.
Depends ... Some salvage yards don't know the difference between it and the normal P71 aluminum driveshaft.

If you get used, would recommend new U-joints (grease-able) and having it balanced.

Got one a few years back from a CrownVic.us member for $150 (included shipping, U-joints, and balance).

And ... As long as you have it out, consider a METCO driveshaft safety loop. :D

http://bellsouthpwp.net/g/d/gdmjoe/MMCinstall.jpg

[vmaxmarauder]

Thank you for the info regarding the driveshaft. the loop will be installed with the driveshaft. The stage 1 mod from what ive read in the SEARCH area is basic upgrades to a n/a vehicle ie; cai, xcal, ud pulleys,gears. bolt on horsepower that poor folks like me can aford v/s twin scwrew superchargers. And for those of you that answer every post with check the SEARCH button dont assume that the person that posed the question did not already spend adequate time searching through tons of posts. If that is your answer dont reply to my post!

[RR|Suki]

Thank you for the info regarding the driveshaft. the loop will be installed with the driveshaft. The stage 1 mod from what ive read in the SEARCH area is basic upgrades to a n/a vehicle ie; cai, xcal, ud pulleys,gears. bolt on horsepower that poor folks like me can aford v/s twin scwrew superchargers. And for those of you that answer every post with check the SEARCH button dont assume that the person that posed the question did not already spend adequate time searching through tons of posts. If that is your answer dont reply to my post!

I don't see what danger you could run into wish a stock drive shaft, unless you are out on the freeway every night doing 130mph for good periods of time.

[Stranger in the Black Sedan]

It would be an upgrade, however, it is no longer available from FoMoCo. You would need to find a used one out of a 2000 P71. *NOTE: Wasn't available prior to nor after that year. Standard issue that year only.


Quote:

Yes it was standard 00 only BUT MANY of the other years had them retrofit due to TSB. So don't restrict your search by year. Go by color band code.

There is an advantage to an MMX. With 3.55-3.90 gears your 1/2 critical speed is right in "I'm a speeder" highway cruising territory (65-75 mph). If you have 4.10s your 1/2 cricital speed is WELL into your cruise speed range, probably right around 50-55 mph. Most people won't notice it but 1/2 critical speed will vibe somewhat. How perfect the balance on the shaft is will affect this and since the cars are production line made, will vary one to another. You typically design a vehicle/shaft combo so 1/2 critical speed is out of the range where you will cruise at sustained speeds (you really don't want a 60 mph 1/2 critical speed) but w/ the MM's extremeley long d shaft, it was not possible.

So moving critical speed up can have benefits even if you don't plan on driving 140 mph. If you cruise at 70 your ride may be smoother w/ a lighter and/or stronger shaft that increases the critical speed.

Entirely too much though but I am very picky. Look for CVPI's on car-part.com and call them up and ask what the 3 band color code is on the shaft. That will tell you for sure whether it is plain AL or MMX. You can find MMX shafts for under $100 easily if you are willing to spend the time to call a bunch of nearby places.

[FordNut]

Been many threads on this subject. With 4.10 gears you risk damage to the tailshaft housing with the stock driveshaft. Some people have had positive results by having a high-speed balance put on the stock shaft. The MMX is no longer available from Ford or from Dynotech, so if you want one it's junkyard time. I think Dennis has one leftover Dynotech MMX in stock.

[cougar9150]

I had my stock driveshaft rebuilt, heat straightened, and balanced after my 4.10's were installed.

Mine is the standard driveshaft with the Pink, Green, and Blue stripes starting from the transmission yoke going back. Cost me about $150 and never had any issues.

The only time I feel any vibration is when my tires need to be balanced again which I do every 5k wether it is needed or not.

There are many discussions on this and some people swear that a MMX driveshaft or aftermarket is needed.

Like gdmjoe said I would recomend a driveshaft loop regardless of what you go with.

[SWOOSH]

Okay, my interest is peaked now. I do a lot of highway driving and had my 4.10s installed 2 months ago. I never heard about the driveshaft needed until now. I previously didn't know this could be an issue, what's the deal?

[Stranger in the Black Sedan]

Look up driveshaft critical speed on the intarweb. It's at whatever driveshaft rpm correlates to a road speed of around 130 mph with our stock DS, assuming stock tire size and 3.55 gears. I also have a spreadsheet somewhere that finds theoretical driveshaft critical speed based on material properties, length, and diameter. It's a shaft speed of 6,xxx rpms, don't remember off the top of my head, 6200 or something around there. That would assume a PERFECT balance and a totally perfectly constructed shaft, which is not obtainable in the real world. Imperfect balance will lower critical speed. I think driveline literature said to assume that you can never exceed 90% of critical speed. The TSB for having to upgrade pursuit CVs to the MMX shaft said it was because high speed running w/ the regular AL shaft would cause early failure of the tailshaft bushing of the trans.

Rebalancing a stock shaft is only going to accomplish so much. You can't make the critical speed of the shaft any higher than that of a theoretically perfectly straight, and perfectly balanced shaft. An MMX shaft will still have a higher critical speed than even the best example of a production stock shaft. I wouldn't throw money away rebalancing a stock shaft. You think a local driveshaft shop is going to have a more expensive balancer than FORD? Unlikely. Most small time shops are going to be using really old equipment and god knows if and when it is calibrated. Just because a shop rebalances and the location and size of the balance weights changes does not mean they made it better. They easily may have made it worse.

[Georges93LX]

What is the color band code for the MMX drive shaft p/n XW7Z-4602-AA ?

[Drock96Marquis]

What is the color band code for the MMX drive shaft p/n XW7Z-4602-AA ?


http://www.mercurymarauder.net/forums/showthread.php?p=674083&highlight=driveshaft#post67408 3

Pink, green, blue in order from the slip yoke.

[gdmjoe]

Georges93LX - What is the color band code for the MMX drive shaft p/n XW7Z-4602-AA ?
In addition to the banding, another hint ....

[DTRMiguel]

What is the purpose of changing your driveshaft? Like if i were to get a matrix drive shaft. What will i gaiin? And why?

[merc]

I had shaft vibration at 90 mph and over. I replaced 2-3 rear transmission seals before receiving my MMX shaft.

[cougar9150]

Rebalancing a stock shaft is only going to accomplish so much. You can't make the critical speed of the shaft any higher than that of a theoretically perfectly straight, and perfectly balanced shaft. An MMX shaft will still have a higher critical speed than even the best example of a production stock shaft. I wouldn't throw money away rebalancing a stock shaft. You think a local driveshaft shop is going to have a more expensive balancer than FORD? Unlikely. Most small time shops are going to be using really old equipment and god knows if and when it is calibrated. Just because a shop rebalances and the location and size of the balance weights changes does not mean they made it better. They easily may have made it worse.

Mine was bent from an accident so it was needed 4.10's or not. I had it rebuilt and balanced done on the advice of the pro's at the shop and it works fine. They do custom shafts and rebuilds all the time. I would trust them for a new 4" aluminum shaft but didn't have the money at the time.

I have driven my car on a daily basis since, short 120+ mph jaunts on the freeway and bridges on a regular basis. I figure the $110 I spent vs the $500 - $700 I would have spent on a new one was worth it. When and if I have problems I will fix it/replace it. If you want to lend me the money for a new expensive ass driveshaft go ahead but I'm not sure when I can get the money back to you. Would I have liked a new one yes, could I afford it at the time no. Budget minded alternative that has worked fine since it was done.

Before vibration; after none.

I'm an engineer by trade, I understand the math but I don't maintain those kind of speeds for extended periods of time cause I'm in the city. Now if you drive at 130 on a regular basis for long periods of time I would recommend a new aftermarket 1. City driving short bursts; have fun until you need it, just get a loop. Plus the MMX shafts are no longer available so a 4" aluminum will probably be necessary.

[mdskiing]

I purchased the LAST METCO driveshaft from Dennis last month......:beatnik:

[wchain]

On my DTR, I took the shaft out and had a local driveshaft place balance the shaft.

I had the car up to 140+ with no vibrations whatsoever.

[Bluerauder]

What is the purpose of changing your driveshaft? Like if i were to get a matrix drive shaft. What will i gaiin? And why?
Safety and peace of mind. My understanding is that driveshaft vibration at high speed/high RPM is an indicator of driveshaft distortion (i.e. bowing) that could cause failure at either end of the shaft. The MMX or the PI driveshafts provide better balance and eliminate (or at least significantly reduce) this vibration. The driveshaft loop is there as an additional safety measure to contain the driveshaft if it breaks or gets loose. I believe that the "loop" is required at NHRA tracks (but I can't recall the ET or trap speed limitations for the loop). Merc knows.