[IronChopz]

Your Mark VIII Drive Shaft Experiences?

Hello, folks...

I am just curious as to the experiences anyone's had with the aluminum drive shaft. I've read the article posted in the Technical Articles entitled " Ford OD Transmissions 101 - Jerry's mod" and learned quite a bit from it.

However, I was asking a transmission shop about an aluminum shaft installation, and they questioned why. I mentioned the article, explaining that the person who wrote it is a Ford Transmission Designer, and that he even suggests the aluminum shaft for this car in this article because of it's higher critical speed.

The shop's reasoning was that aluminum isn't as strong, thus, it is more susceptible to breakage, and probably will break ("We see it all the time on Aerostars! Stay with steel.").

If these shafts were breaking, I'd imagine there'd be a recall, TSB, or flat-out 'no more making of them.'

One last item: is the 4R70W a type of AOD-E? Or are they different beasts? The article states the 1994 T-bird has the 4R70W, but a transmission shop said I have an AOD-E transmission (I even saw a part that had AOD-E printed on it while the transmission was being inspected).

Just curious, as I've already obtained the aluminum shaft, but it awaits installation. Going to aluminum, to me, makes sense, simply because a good percentage of my driving is sustained higher speeds (interstates mostly).

 

[WhiteBird101]

You said you read j's trans 101? The answer is in there, last page i think. Driveline critical speed. Its true that steel is stronger, but it is also heavier. More rotational mass, and that lowers the speed the shaft can be spun at. Aluminum is MUCH lighter, thus less rotational mass, thus it is capable of a higher rate of "spinage" That is a VERY basic explantion, and j's article goes into MUCH more detail. Find some way to print it, and rub it in their face.
As for the transmission. Yes, the 4r70w is a FORM of aode, but it has several differences, and those differences are outlined in the trans 101 article. Personaly, i would try to find a trans shop that knew what your trans is, but thats just me.

 

[392Bird]

I know that the aluminum ones will allow higher shaft speeds, with out problems, but this brings up a question. How have we got by with out them for decades. I have owned MANY cars over the years with out
ever having a problem like this. I guess the fastest was 67 Mustang GT that we put in a 427 Ford 4 bolt crate engine, and did extensive mods to it. This car turned 135-140 in the quarter running 4.88 rear. No vibrations!

I had this car in Germany, and drove it on the highways some during off season with 3.7? gears in it, and std front shocks. I would cruise on the Autobauns where there were no speed limits at 140-150, and NO vibration! So tell me, are they building the steel ones so sloppy now, that we have to get a after market one for the cars to go over 105 with out vibration?

What is the REAL reason for this? Why do the steel shafts of today, vibrate at a shaft speed much lower than prior years? Has our manufacturing quality dropped that much, or is there a new factor?
Inquiring minds want to know

 

[WhiteBird101]

Well one big reason is the mn12 chassis is VERY sensitive. Even a slightly misbalanced tire could lead to excessive vibration. I'm also willing to bet that manufactor quality has decreased some, you know, quanity over quality.

 

[zenbanshee]

Length has something to do with it . . .

Our driveshafts are much longer than the drive shaft of a mustang (something like 65" vs. 45"). That means that the frequencies (rpms) that cause our driveshafts to have problems are much lower.
Aluminum, along with being lighter than steel, also vibrates much less. Get a bar of steel and a bar of aluminum and tap both with a small hammer -- the aluminum bar goes "thud" and the steel bar rings for five minutes.

 

[4 Cam Bird]

The Mark VIII that the Aluminum driveshaft comes out of has 75 more HP and 30 more Ft lb, there is no way you are breaking this shaft in a Thunderbird. I would steer away from the tube in tube (referred to often and incorrectly as a two piece) that came in the 94 and newer Mark's, my dad had this type of shaft in a vehicle once and it came apart and left us stranded...so it was behind a blown big block Chevy 402, still better off with the single tube.

 

[WhiteBird101]

Tube in tube is still technicly two-peice. lets see, 1+1 still equals 2, right?

 

[IronChopz]

Tube-in-Tube...?

For anyone:

How does tube-in-tube differ, mechanically, from a one-piece shaft? What pros and cons are there? Since I am new to the tweaking and modifying world, I figure it's best to gather information as I go. I'm not going to go for 300hp+(I have a teen-aged son who just obtained his permit!), but I do plan on adding the Richard MacCutcheon-designed intake tube, perhaps some underdrive pulleys, and definitely a chip from Dennis at Reinhardt Automotive.

 

[WhiteBird101]

I think the two-pieces biggest problem is it is sigingicanlty harder to balance than a one piece, but they are cheaper for manufacturers to mass produce, so they are used instead. Two-piece really have no advantages, other then price. One-piece are stronger, easier to balance, etc.

 

[BigBird101]

Hey iron chopz, my advice to you is get your son a nice car but a slow one. Believe me, my son had a V-8 bird with some mods and he got 3 speeding tickets in 6 months. I was stupid to get him an even semi fast car. Go for a V-6.

 

[WaLieN]

Hey iron chopz, my advice to you is get your son a nice car but a slow one. Believe me, my son had a V-8 bird with some mods and he got 3 speeding tickets in 6 months. I was stupid to get him an even semi fast car. Go for a V-6.

It's really the person. I'm 16, and I've had my Tbird for about 3 months, not one ticket. I guess other things could be tossed into this, but if you're going to get him a V6 Tbird, I wouldn't even get a Tbird. The only reason I got the Tbird was because it was...

1. Within my budget
2. It has some balls behind it (4.6L)

if it were not for the V8, I wouldn't have even gotten it. The 3.8 is pretty weak, compared to the 4.6, and gets about the same gas. Really, it would just be a much better choice to get him a 4.6. If you want him to be safe and not go fast, then get him an old Corolla.

 

[MagerThom]

Re: Your Mark VIII Drive Shaft Experiences?

Hello, folks...

One last item: is the 4R70W a type of AOD-E? Or are they different beasts? The article states the 1994 T-bird has the 4R70W, but a transmission shop said I have an AOD-E transmission (I even saw a part that had AOD-E printed on it while the transmission was being inspected).

Just curious, as I've already obtained the aluminum shaft, but it awaits installation. Going to aluminum, to me, makes sense, simply because a good percentage of my driving is sustained higher speeds (interstates mostly).

All '94-97's are 4R70W 's ...they are similar to AODE...the
"W" stands for wide gear ratio.

I bought a Mark VIII D/S new fron DanN..had it to over 120+ mph
and its' dead smooth.

 

[IronChopz]

Thanks, Mager, for the info.

...it's pretty much what I figured.

BigBird: no problem on that. The T-bird is mine, and for a long time, too! He's just doing his permit driving (with me) in it.!

 

[BlackCat94]

A slow car is NOT a safe car

If you put your kid in a car that can't get out of it's own way how in the hell is it supposed to get out of an 80,000lb truck's way? I think a 3.8L will move a HEAVY car with enough force to stay safe, but there are some cars I've driven and felt concerned about the fact that you can't get on the gas and get out of another vehicle's way.

 

[IronChopz]

This Thread Is...

...regarding the aluminum drive shafts, and related experiences people have had with them, driving, installing, tech. tips, etc.

I never mentioned I am getting my son a car. I have no intention of doing so. My comment was that I have him drive my 'bird for his logged driving time in accordance with the MI Sec. of State's requirements for teen drivers.

These forums are great...I wish I had known about them a couple months before I found this site.

Thanks to all who've contributed!

--Pete

 

[About2beBAD]

Ah, the good old days..

I remember when I was 16. My mom used to have an escort station wagon... A drunk driver hit her, totaled the car. She got a 91 5.0 bird.

She really, really shouldn't have let me drive it....LOL

 

[Jurgen]

Just get ur son something that he likes so he doest ask u next year about another
car and if he wants a bird even if its a v6 or v8 if hes going to drive fast he will get tickets
with any car i went from 0-8 points in less then a year since i got my bird
and now they got me on probation but since i been going to the track i havet had my mind
on raceing every car that pulls up next to me

check my site http://jurgens94bird.streetracing.org/

 

[chilipepprflea]

how will i be able to tell by looking at it, that it's a 93 markVIII one piece? can you see the difference on the outside between the one piece and the tube-in-tube design?

 

[Blown94SC]

chilipepprflea

Drop me an e-mail @ [email protected]

Jim