Something doesnt seem right to me with this tranny - driveshaft connection

[azgolfrat]

Hey guys, I guess I am paranoid, but something doesn't seem right to me here. Why is there an oring in the drive shaft flange (not viewable in this photo) if that flange doesnt contact anything, as seen in this photo. Is there a part missing?
I pulled out the tranny and had it rebuilt at a shop and then I dropped it back in with rebuilt engine. The drive shaft has been sitting in my garage for 12 months until I put it back in just a couple days ago.
what do you think?
Thanks
-KK

Attachment 51447

[hotford]

HMMM……

The DS is a factory piece and does come with the vibrationdamper, this is stock.

You say the trans was rebuilt, did they rebuild the originaltrans or have a replacement rebuilt one installed??

Mustang trans are different lengths vs Crown vic/Marauderones.

[Blown3.8]

The Marauder has a longer tailshaft to keep the driveshaft shorter for less deflection at high speeds. If the rebuilder used a short tailshaft the entire trans would have to be pulled apart to change it out, as that is the first part to be installed on a rebuild.

On that note, I have no idea why he would have changed the tailshaft unless you broke it which is not likely.

I hear there is a spacer you can use at the rear end to correct this. I don't think I would use that tho with your V7-JT blower.

[azgolfrat]

Guys, thanks for the inputs. I have some before-rebuild-shop and after-rebuild-shop tranny photos.
I cannot see a difference in the length of the tailshaft between those photos. But they are not the greatest photos.
I guess there is a chance the guys at the shop swapped out the tail section, even though my photos make that hard to verify

Is there an ID on the tailshaft that would help me ID it as a marauder tranny tail shaft (or not)?
Also, does the gap seen in the below photo make it certain that the tail section in the wrong one? That is, should there be no gap?

I am still confused as to why there is an oring in the disc flange at the tranny end of the driveshaft. What is the purpose of it?
I've posted a photo from different angle view below which might help you in assessment
Attachment 51448

[azgolfrat]

HMMM……

The DS is a factory piece and does come with the vibrationdamper, this is stock.

You say the trans was rebuilt, did they rebuild the originaltrans or have a replacement rebuilt one installed??

Mustang trans are different lengths vs Crown vic/Marauderones.

Hot ford, as far as I can tell they rebuild the original trans. I'm working on verifying this. As I say below, my before shop and after shop photos dont look very different.
What is the vibration dampner you mention?
Thanks very much for your inputs.
I'm getting close to start up after 1.5 years of work...hoping this doesn't derail me.

[RubberCtyRauder]

Cop car crown Vics have the same tailshaft housing. Aluminum driveshaft cars had them..regular crown Vics and Marquis had steel driveshaft.. ADTR.net has the spacer

[RubberCtyRauder]

https://adtr.net/kb/crown-vic-driveshaft-swap/

[blazen71]

The lighter color "wear mark" on the slip yoke should be just under the tailshaft seal. Looks to be sticking out past the seal about 1/2"-3/4". The o-ring you are describing appears to be the rubber bonding that holds the outer steel ring to the slip yoke, same as a harmonic balancer.

[azgolfrat]

OK,
So the story gets a little better. It's my understanding that the yoke (pictured above) is not stock on the Marauder.
It comes stock on non PI crown vics and Grand Marquis.
So..when I bought the car back in '19, it had this non stock yoke on it , unbeknownst to me. Why? Someone changed it, or the guys at Ford made a mistake while building.

Now, it seems this occurrence (non stock yoke) is a good thing because this yoke (the one pictured above and currently on my car), though shorter, has a longer length of splines on the inside, which mates into the transmission (more contact with transmission mating spline). However, it could be a bad thing because the overall length of drive shaft + yoke is shorter that marauder stock driveshaft + yoke - thus less contact with the tranny splines. :/


I think this is where the spacer comes in. Does the spacer go at the back of the drive shaft where it connects to the differential and make the entire length just long enough?

And I'm still not sure if I have the longer tailshaft on the tranny or not.

Thoughts?
Thanks very much all for the input!
-KK

[RubberCtyRauder]

Do you have a steel or aluminum driveshaft? Marauders came with aluminum. Did you look at ADTR website? Read the link I posted about driveshafts

[justbob]

The Marauder has a longer tailshaft to keep the driveshaft shorter for less deflection at high speeds. If the rebuilder used a short tailshaft the entire trans would have to be pulled apart to change it out, as that is the first part to be installed on a rebuild.

On that note, I have no idea why he would have changed the tailshaft unless you broke it which is not likely.

I hear there is a spacer you can use at the rear end to correct this. I don't think I would use that tho with your V7-JT blower.

That’s odd Chris. Are they set up any differently than other 4R70’s? I’ve never rebuilt a trans but I did replace the cracked tail shaft on my last work van, an ‘03 E250. They were actually in stock as it’s very common to crack on trucks, so much so that the local dealer is under contract apparently with the local gas company to always have certain numbers of parts on hand and tailshafts were on that list.

All I remember was it was quite easy to swap out in place?


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[justbob]

That rubber on the yoke is stock.



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[azgolfrat]

Yessir, Aluminum. The link was helpful. Thanks.
Been on the phone with Chris at ADTR a bit today - as always he is very helpful.
That link has a pretty good video in it as well.
My extension housing is a 78039-AA and is 11.5 inches long.

[Blown3.8]

That’s odd Chris. Are they set up any differently than other 4R70’s? I’ve never rebuilt a trans but I did replace the cracked tail shaft on my last work van, an ‘03 E250. They were actually in stock as it’s very common to crack on trucks, so much so that the local dealer is under contract apparently with the local gas company to always have certain numbers of parts on hand and tailshafts were on that list.

All I remember was it was quite easy to swap out in place?


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Yeah, my t birds use the shorter shaft and housing. The housings are easy to replace the actual shaft is not. It's the 1st part to be inserted into the case on a rebuild.

Back in 2018 we went to a race in PA 1 week before we were scheduled to do drag week. And broke something in the trans. I had sold an old built trans to a buddy for his t bird. He never got around to using it, so we bought it back. Great thing was he lives in PA and was on our way back from the track. Bad thing was we had to change the tail shaft and housing to fit the marauder. So then I had to go to Roanoke so my other buddy could tear the whole thing apart to replace the shaft. Then the speed sensors were different and I had to locate that. Luckily there is a certain one from ford that interchanged. And of course the OSS reluctor needed changed in the tune. So all the fun for drag week that year happened just before the start.

There are different grades of the long tail shaft. I believe you want the one with the long splines because it doesnt neck down at the end of the splines. Like the one in my pic.

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[Blown3.8]

Yessir, Aluminum. The link was helpful. Thanks.
Been on the phone with Chris at ADTR a bit today - as always he is very helpful.
That link has a pretty good video in it as well.
My extension housing is a 78039-AA and is 11.5 inches long.

Looks like you are ok with what you have. I didnt remember that ours hung out so far also. Your housing should have a F3UP number to be the correct length.

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