Okay guys...getting very close to putting this darn thing back together. Here is my dilemma: I need to replace the transmission. I have a 4r70w out of a 2002 Crown Victoria sport. However I noticed the tail shaft housing lengths are slightly different. Can I simply swap housings and be good to go? I sure hope so!
Transmission tailshaft housing question
- Thread starter Chayton
- Start date
crownvic05
New member
Yes, swap tail housing.
RF Overlord
73 is the best number.
I think there will be an issue, but PM 88grandmarq first. He's the expert.
Comin' in Hot
Supporting Member
No.... the answer is no. I probably have more experience with this issue than anyone here. Which transmission has the shorter tail housing? The one you’re going to install or the one you’re taking out?
Well ****. I did some more research online and apparently I should be able to???? The transmission I’m installing has the shorter tailshaft housing.
crownvic05
New member
Crown vic sport has the short tailshaft housing. Either use one from a p71 or the marauder
Comin' in Hot
Supporting Member
The Crown Vic guys will tell you this is OK. But let’s face it, they do things you should never do to your vehicle.
The Issue : The driveshaft is too short, causing improper spline contact. You could install the longer tail housing and use your current driveshaft, but the problem is your yoke has recessed splines. This means there is 1” less spline contact. When I bought one of my marauders it had the shorter output shaft and tail housing with a standard marauder driveshaft. The splines twisted the inside the yoke just enough that the yoke would not slide correctly, but not enough to see easily.
Solution #1: Get a driveshaft that is the correct length. Marauder length +1 inch.
Solution #2: Get a 1” spacer mounted between the pinion flange and the driveshaft flange.
The Issue : The driveshaft is too short, causing improper spline contact. You could install the longer tail housing and use your current driveshaft, but the problem is your yoke has recessed splines. This means there is 1” less spline contact. When I bought one of my marauders it had the shorter output shaft and tail housing with a standard marauder driveshaft. The splines twisted the inside the yoke just enough that the yoke would not slide correctly, but not enough to see easily.
Solution #1: Get a driveshaft that is the correct length. Marauder length +1 inch.
Solution #2: Get a 1” spacer mounted between the pinion flange and the driveshaft flange.
Comin' in Hot
Supporting Member
There’s also a third solution, which involves tearing apart the transmission and changing the output shaft to the longer one, but it’s not at all practical.
Comin' in Hot
Supporting Member
When I say the Crown Vic guys, I’m referring to the guys that take a car with a steel driveshaft and put in a P 71 aluminum driveshaft that is 1” shorter. They are the guys that tend to change the tail housing and think it’s OK without changing their output shaft. I’ve had this argument with them and gave up. They think there’s nothing wrong because once it’s installed it looks like it’s right, but none of them think about the spline contact. Or they don’t have enough horsepower to destroy the yoke/output shaft.... i’ve also heard of the tailhousing bushing failure with this mod but nobody understand seems why it happens lol.
crownvic05
New member
I havent had an issue with my set up on my 05 sport. 5 years running strong with 3.73, marauder drive shaft and extended tailshaft housing. Over 40k miles and ive pushed it hard on occassions. Just speaking from personal experience.
Comin' in hot does have a point though but omce again, i havent had no issues and i know lots of crown vic members with same set up with no issue either.
Comin' in hot does have a point though but omce again, i havent had no issues and i know lots of crown vic members with same set up with no issue either.
crownvic05
New member
So now you have me wondering if my set up is right. I dont have the horse power to worry about it but its good to know
Comin' in Hot
Supporting Member
Sorry. Lol.
88grandmarq
New member
yep, the issue is the output shafts are different and the slip yokes are different to match the output shaft.
marauder, town car and CVPI use the long output shaft, which is not splined all the way up and has an o-ring to seal it. the slip yoke matches this and is smooth in the first half and splined at the end.
you can use the shorter output shaft with this slip yoke, but you end with only a 1/4" of spline contact because the inside of the slip yoke is not splined all the way.
marauder, town car and CVPI use the long output shaft, which is not splined all the way up and has an o-ring to seal it. the slip yoke matches this and is smooth in the first half and splined at the end.
you can use the shorter output shaft with this slip yoke, but you end with only a 1/4" of spline contact because the inside of the slip yoke is not splined all the way.
Attachments
So but if I use a 1” spacer I’ll be fine ?
Comin' in Hot
Supporting Member
As far as I could tell it’s slightly over an inch difference. I had custom biliet spacer made, that I no longer need. Shoot me a PM if you were interested.
http://i22.photobucket.com/albums/b335/Witman40/5c44d574.jpg
crownvic05
New member
Can you please post a pic of the other end if you don't mind. This would be where it goes into the tailshaft.
If our friend don't buy it off of you, I might be interested.
Comin' in Hot
Supporting Member
I don’t have a picture of the longer tailhousing with the shorter output shaft.... I would think it would look like nothing is wrong. You wouldn’t be able to tell until you removed the driveshaft. The output shaft wouldn’t be sticking out of the tailhousing at all.
