Dropping the drive shaft

[don4331]

I used the site www.car-part.com - they have list of parts and costs.

And yes, it would be at least '93 or newer...well for sure, '98 or newer. And yes, it would just slip into the transmission and it should bolt right up to the axle.

Personally, I would replace the u-joints before I installed, because the last thing I would want to do is pull the driveshaft next week to replace them. If either the transmission or axle ends are wrong, you can take opportunity to swap.​

1 piece should go in any position - that's the beauty of it.​

 

[muwaha]

@don4331 I stopped by Bama Parts today and the only one that they seem to have is a 2003 Extended Ranger driveshaft. it's about 3 times the size of mine is now (diameter wise, not the ends, but the Shraft itself, the part that goes in the transmission and rear axle seems to be the same) and it's priced at $100 (which I'm not complaining).

I actually don't care it's that high because I think it's still a good deal. I just want to make sure that it will fit on mine before I bought it since honestly I never got a part from them and not sure of their return policy (which dummy me forgot to ask).

Could I ask you or someone else to help me verify if this would actually work?

 

[don4331]

@muwaha: Yes, the diameter of new one will be much larger than your old one as it is probably aluminum and much lighter. If the distance from the u-joint at the front to the u-joint a back is within a smidgeon of the same total length as your 2 existing pieces, you're golden. (It should be just a little shorter as it will go directly from transmission to axle, no detour to the bearing in middle). I am 99% sure it will work, but a tape measure is your friend.

The boring engineering - you have to be careful that you don't get "whirling" as it was known in my design text book which is an uncontrolled vibration when spinning.*

Whirling is caused by gravity and imbalance and the rotation speed. Every shaft will "whirl" at some speed, the idea is to make the speed MUCH higher than normal drivings
The longer a shaft is, the more it sags, the more "flexible" (lower modulus of elasticity) and the greater the imbalance, the more prone it is to whirling.

To combat sag; you can do 5 things:

1. make the drive shaft shorter, (initially Ford only made regular cabs, then they came out with SuperCab, but they weren't sure how many SuperCabs they would sell, to they added short extension ahead of the regular rear, so they wouldn't have volumes of unused SuperCab driveshafts if it turned out, no one wanted the bigger cab. It turned out the SuperCab sold very well, so, they cost reduced by making 1 piece drive shaft <1 less u-joint, 2 fewer driveshaft ends, no carrier bearing and no bolt hole in the frame cross member, but it comes with drawback it needed to be stiffer ).​

2. make it out of stronger, lighter material (e.g carbon fiber, not steel. Aluminium is going wrong direction for strength, but it is lighter, so they kinda balance)​

3. make the drive shaft out of thicker material (use 0.125" material, not 0.090", helps but makes driveshaft heavier - more material costs more)​

4. make the diameter of the driveshaft larger, (use 5" tube not 2-1/2 and makes it 4X stronger for only 2X material, which is good value for the dollar)​

3. balance the driveshaft better, (Ford was making 100s/day, spending time to get perfect balance would cost too much, so they are balanced close and shipped.)​

​

So, as it is longer and made of thinner aluminum, it needs to be larger in diameter.

Hopefully, that helps with both answer your question and allow you to understanding of why.

*In our CNC machining class, we attempted to make a brass cannon. When we turn on the lathe, the brass rod bent like it was play dough and we barely got it emergency stopped before damage was done. The 3 cm diameter x 25cm long brass rod was bent 90* to the lathe chuck.

 

[muwaha]

@muwaha: Yes, the diameter of new one will be much larger than your old one as it is probably aluminum and much lighter. If the distance from the u-joint at the front to the u-joint a back is within a smidgeon of the same total length as your 2 existing pieces, you're golden. (It should be just a little shorter as it will go directly from transmission to axle, no detour to the bearing in middle). I am 99% sure it will work, but a tape measure is your friend.

The boring engineering - you have to be careful that you don't get "whirling" as it was known in my design text book which is an uncontrolled vibration when spinning.*

Whirling is caused by gravity and imbalance and the rotation speed. Every shaft will "whirl" at some speed, the idea is to make the speed MUCH higher than normal drivings
The longer a shaft is, the more it sags, the more "flexible" (lower modulus of elasticity) and the greater the imbalance, the more prone it is to whirling.

Would there be anything I can do to try to combat the whirling? or would it be like just getting another one?

 

[don4331]

Would there be anything I can do to try to combat the whirling? or would it be like just getting another one?

Ford engineers have done all the work for you already. Unless you are trying to set a new land speed record (spinning the driveshaft extremely fast), you won't have an issue.

It's more of an issue for one of your fellow RangerStation members. He has lowered his Ranger 5" and as a result the large diameter driveshaft is contacting the cab. He is going to need to reduce the diameter of the driveshaft and it might cost him a fancy carbon fiber shaft to avoid "whirling".

 

[muwaha]

Ford engineers have done all the work for you already. Unless you are trying to set a new land speed record (spinning the driveshaft extremely fast), you won't have an issue.

It's more of an issue for one of your fellow RangerStation members. He has lowered his Ranger 5" and as a result the large diameter driveshaft is contacting the cab. He is going to need to reduce the diameter of the driveshaft and it might cost him a fancy carbon fiber shaft to avoid "whirling".

Ok, So I don't have anything to worry about on mine since I do not ever plan on messing with the height of it. Unless the height of my truck changes when I get the suspension checked/replaced.

 

[don4331]

Ok, So I don't have anything to worry about on mine since I do not ever plan on messing with the height of it. Unless the height of my truck changes when I get the suspension checked/replaced.

Correct, nothing for you to worry about.

For those of us who modify our trucks, we need to take care.

 

[muwaha]

Welp I ran into an issue.
Finally got the center bearing, I slip it on but I can't get the yolk to go far back like it was, with the old bearing the yolk went back 10/16s from the half curve to the end of the bolt.

With the new bearibg, the yolk only goes back 5/16s.

I can't get the yolk to go any further back but the bearing still has wiggle room.

I've used grease, pb, wd40, with a hammer and block of wood.

any thoughts?

 

[muwaha]

I put everything back on as tight as I could with the 2piece driveshaft and it seems to work fine now.
I get a squealing sound occasionally but maybe it's because the bearing hasn't been broken in yet?

I'm still looking to get the solid 1 piece though so hopefully my truck can last long enough to pick it up lol.