[ponys4ever]

i just put an older 25 spline 4 speed Top Loader in my 66 Fastback. Today i went to install the drive shaft found i do not have enough clearance at the rear to set the back of the drive shaft in the rear. i loked hard at the slip yoke and see it is not going in all the way to the U joint. Does this mean that there is something wrong with my OUTPUT Shaft? I f there is something wrong with can i remove it without removing the entire tranny or is the whole trans going to have to come back out?

the only thing that was changed in restoration was i took the C4 out and replaced it with the Top Loader. everything else is from the original car.

Any help or advise would be appreciated.
Thanks jerry

 

[22GT]

Do you have a 25 spline shaft and 25 spline yoke? If there is some thing wrong with the shaft, other than the design flaw that breaks them, you may want to install a 28 spline shaft. Yeah, I know, it's a pain.

 

[ponys4ever]

I have no problem with replacing the output shaft but if i have to do it i am wondering do i have to remove the entire transmission or just the tail shaft section. never rebuilt a trans before.

ps i was told the 25 splines were prone to twist which could cause my symptom.
Jerry

 

[22GT]

Precisely. I saw one just a couple months ago that acted exactly as you describe. Extremely close examination revealed a few thousandths of helical twist in the splines.

I suspect the repair would be a LOT easier if you pull the trans.

 

[cormy1]

About how much of a difference do you need to make up at the rear spline?

can you pull back on the shaft to mate the rear and have enough for proper engagement off the tailshaft slip yoke?

 

[supershifter2]

i twisted the splines of a 31 , yes 31 spline output shaft on a toploader once (and shot it twice) and had to take a hammer to the front side of the yoke and beat it OUT and then replaced the output shaft and stuff and never did what i did agiain that twisted it. try hitting the front side of the yoke with a hammer (ye ole ford tool) ! its possible that the tailhousing was tightened up without a yoke in place and that can cause the tailhousing to be slightly off center and you can try loosening the 5 bolts that hold the tailhousing on but drian the oil out first.:deadhorse::shaking:

 

[roadracer]

I have no problem with replacing the output shaft but if i have to do it i am wondering do i have to remove the entire transmission or just the tail shaft section. never rebuilt a trans before

It is simple to remove the tailhousing of a toploader by loosening the 5 bolts holding it on and slipping it off with the transmission in place. You need to drian the fluid, remove the speedometer drive cable, rear support and shifter. Support the transmission with a jackstand while you do this. Be care not to let the rear output shaft roller bearing (captured in place by the tailshaft housing) slip out of the main case while doing this.

This will allow you to test fit the yoke and figure out the problem.

If the output shaft needs replacement, you must fully remove the transmission from the car.

 

[ponys4ever]

Well men looks like i have to pull the trans tomorrow. i am pretty sure the shaft is twisted at his point. i was hoping for a simpler route as i have just installed all of this in the last two weeks.
thank you men for your help.
Jerry

 

[Mustangerbob1]

I would like to know how you are bolting the transmission to the bell housing and the bell housing to the engine. 25 spline toploaders were for the 5 bolt engines 62 - 64) and have a narrow face mounting flange. The bellhousing for it does not fit against the 6 bolt (65 and up). IIRC, there was only one bellhousing that will work and it was a cast iron truck transmission, and the depth is wrong for a Mustang.

The only other time I saw this even close to working was someone who have taken a 6 bolt bell housing and drilled the narrow pattern onto it, and then bolted the transmission to the bell housing. The problem was the spots that matched were not ribbed or reinforced in the bell housing, and the transmission was tearing the bell housing apart.

Bob

 

[supershifter2]

I would like to know how you are bolting the transmission to the bell housing and the bell housing to the engine. 25 spline toploaders were for the 5 bolt engines 62 - 64) and have a narrow face mounting flange. The bellhousing for it does not fit against the 6 bolt (65 and up). IIRC, there was only one bellhousing that will work and it was a cast iron truck transmission, and the depth is wrong for a Mustang.

The only other time I saw this even close to working was someone who have taken a 6 bolt bell housing and drilled the narrow pattern onto it, and then bolted the transmission to the bell housing. The problem was the spots that matched were not ribbed or reinforced in the bell housing, and the transmission was tearing the bell housing apart.

Bob

my mcleod and my lakewood have both the narrow and wide bolt patterns. many many years ago i knew a guy who said he had to drill holes in a factory bellhousing and bolt the trans to the bellhousing with nuts and bolts and install it like that , i saw the mustang but never looked under it.

 

[ponys4ever]

Men,
i bought the bell and the trans from same guy. i mounted it right up and did not have to drill anything out. i have separate pictures of the two pieces if you would like to see them but i would need you email to send it. everything mounted up to engine pretty well.
lmk if you want to see the photo's. my email is jdyarbrou@yahoo.com

thank you guys for all your great insight.
Jerry

 

[22GT]

The later "hourglass" shaped flange was drilled for the rectangular bell.

There are no absolutes, either. This is the 25 spline I referred to above (which now has a 28 spline shaft):

 

[ponys4ever]

RESOLVED.........
Found my problem....the 25 spline slip yoke was made incorrectly. tried two new ones and the both failed tried a used one worked great. trans was out and now back in and the guide bolts were the trick so thank you very much.