Broken rear drive shaft ears!!!

[98 Bulldog]

Hey all, I'm new here but I need some help. My 98 expy was recently towed by my neighborhood scam/tow company. Upon getting it back, I took it for a spin around my development and heard a loud rumbling/shaking from under the truck when I accelerated. I let off gas and it stopped but when I accelerated again it worsened. Only to hear a dragging sound and I noticed my rear drive shaft had snapped at the ujoint ears on the rear end side. That is made of cast steel and I don't know how this just suddenly happend. The four bolts and the end yoke are still attached to the rear but the rest of the shaft is in my basement. Help me out if you have any insight!

 

[stamp11127]

Pics of the driveshaft and rear yoke would help.

 

[98 Bulldog]

Here it is where it broke from rear end

 

[toms89]

Its possible they attempted to tow or pull it with the rear wheels on the ground and with it in park. This locks the transmission output shaft thus your driveshaft but really would expect the tranny park pawl to brake first.

Its also possible they noticed this as the truck did not want to move and put it in neutral but the damage had already been done.

 

[01yellerCobra]

My guess would be they hooked it from the front and drug the rear tires. If the driveshaft isn't bent or twisted you could probably get away with a new u-joint and flange. I would check the tailshaft housing on the tranny for cracks as well.

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[98 Bulldog]

It was backed in so Im sure they pulled it and caused the back wheels to drag. I checked all the gear patterns on the tranny and they all shifted normal. If the tranny checks out good, is it possible that a new driveshaft will solve this issue? Or could the rear be destroyed? The drag marks in my parking space were no longer than 10-12 inches or so...

 

[toms89]

It was backed in so Im sure they pulled it and caused the back wheels to drag. I checked all the gear patterns on the tranny and they all shifted normal. If the tranny checks out good, is it possible that a new driveshaft will solve this issue? Or could the rear be destroyed? The drag marks in my parking space were no longer than 10-12 inches or so...

My guess is the rear end will be fine. Does park work? Any resistance getting it in or out?

Guess you really wont know till you replace driveshaft......

 

[toms89]

I am going to re-word this for clarity.

Yes I believe the rear differential will be ok. The ring and pinion in these are very beefy. The weak links would be the parking pawl and u-joint. I would not be surprised if the parking pawl was damaged as well. This could make it more difficult to get in and out of park or park simply may not work anymore. If you replace the driveshaft you will know if park works or not. I would not be surprised if you have end up with a high speed imbalance due to the driveshaft not being indexed exactly as it was but this should be minor. If the driveshaft is bent you will have major issues.

 

[98 Bulldog]

Installing new drive shaft tomorrow. There wasn't an issue putting it in park once I got it back in front of the house except a loud whining noise like an alarm clock coming from underneath the truck near the front. Perhaps in the area of the torque converter or near it. I never heard it before but remember when I put it in park the rear driveshaft had already fallen out. Could the noise I heard be a result of putting it in park w/o a driveshaft? Just very confused how the shaft could just lock and once I attempted to drive it how could it stay locked and break as a result! The ujoints were still in tact except for a couple end caps that flew off... Confused

 

[toms89]

Installing new drive shaft tomorrow. There wasn't an issue putting it in park once I got it back in front of the house except a loud whining noise like an alarm clock coming from underneath the truck near the front. Perhaps in the area of the torque converter or near it. I never heard it before but remember when I put it in park the rear driveshaft had already fallen out. Could the noise I heard be a result of putting it in park w/o a driveshaft? Just very confused how the shaft could just lock and once I attempted to drive it how could it stay locked and break as a result! The ujoints were still in tact except for a couple end caps that flew off... Confused

The driveshaft is only "locked" when the transmission is in park and prevents it from spinning. This is intentional in the design to keep the vehicle from moving. When they try and tow it with rear wheels on the ground something has to give. Tires slide locked up on pavement, breaks the parking pawl inside the transmission or driveshaft U-joint.

I am not saying the driveshaft locked up as a result of the towing incident, just that the breakage is likely a result of it. It could have stressed and cracked the u-joint and it didn't completely break until you attempted to drive it.

Hopefully the whining noise was just the tranny internals spinning without the driveshaft being attached or there may be more too it.

 

[98 Bulldog]

Ok that makes perfect sense. One more thing, will the stress that may have been inflicted, cause the actual cast steel on the shaft ears to literally shear off like that? I understand that the output shaft locked and thus locked the shaft, but what type of force did I put it under simply cruising that led to that type of complete breaking of the steel? My concern is eliminating the likelihood of rear end being shot. I feel like the tranny is fine and prior to being towed the rear was perfect!!! Ok Im really hoping the shaft was only binded as a result of the tow which led to malfunction because as you can see from pic the ujoint itself did not break! I apologize if Im repeating myself somewhat I just wanna get a clear understanding as well as give you guys all my concerns...

 

[toms89]

There are no guarantees but I can tell you from many years of drag racing that U-joints break far more often than the rear differentials. Drag racing test the limits of these components due to the violent launches. The ford lightnings use these rears (9.75") and I have yet to hear of any breaking one.

Once you stress or crack the u-joint it generally will fail in dramatic fashion shortly after.
You will find out soon enough after you replace the driveshaft.

 

[98 Bulldog]

Is there any sure fire way to determine what tranny I have? I have been calling my local junkyard to get the driveshaft but they are asking me which tranny I have and I dont know and I dont know how to find out... Any idea guys? Its a 98 xlt 4x4 and I do have the overdrive button on the gear shift...

 

[FordandPolaris]

Grab the transmission code off of the door placard and put it into google "Ford transmission code ____"

That should tell you what it has in there from the factory.

 

[98 Bulldog]

Ok I got you... Its a E40D. Thanx for the help

 

[98 Bulldog]

Ok I replaced the driveshaft and the issue remains... BUT I think I see why. Both of my rear control arms are completely broken. The entire rear end moves when put in gear because of lack of stability. How do they break? Is this a simple repair? Where can I purchase the arms?

 

[FordandPolaris]

That is not good, I would not recommend driving the truck until you can fix those as they are extremely important. If you lose the upper control arms as well, you will be picking up your rear axle separate from your truck... Basically it was a bad design by Ford from the factory. They had a small opening in them that would allow snow and water to be jammed up in there. Over 15 years, they tend to rust through, eventually breaking. I replaced mine with PMT rear control arms to replace mine. I had holes about the size of a quarter through each one. Here is a link to the arms I used. They are spendy, but are a very solid design that will never give you problems. They are not terribly hard to fix, but the bolts are almost certainly locked in tight. I had to use a sawzall to remove the pieces.

PMT Fabrication. 97-02 FORD EXPEDITION LOWER REAR CONTROL ARMS

 

[Lightnig]

Thats good to know, thanks F&P.

Now I know the next thing I have to check out on the truck before I get any nasty surprises.

That is not good, I would not recommend driving the truck until you can fix those as they are extremely important.

...

Important indeed, please don't drive that truck until fixed. I would think that it is pretty close to uncontrollable as it stands now. I can only imagine what it like going over bumps as it is...

 

[FordandPolaris]

Yeah most expy's I have seen have the holes in them already. I know there are some who have just fabricated their own as well. If you have a welder, it is something to consider. My mind is much more at ease though with the new control arms. The uppers usually are not nearly as bad. They are the same type of design, but the opening faces the side as opposed to straight down, so I do not see nearly as much rusting on those. Mine are still stock.

 

[Lightnig]

I looked at the link you posted, and that was my exact thought (I was a welder by trade in a former life).

A set would be super easy to fab up, problem being is that by time a guy got through buying the hardware and driving around to buy such a small quantity of material the cost would not be that much less than just buying these new ones.

But if a guy had the stuff on hand (as is worked in a fab shop), that would be a completely different matter...



Also, just checked rockauto and even their cheapest one is over $150 a set. The ones you posted up look much better quality.