MTFCA Forum

I am working on a minimally touched 15 transmission.
The correct thick clutch disk is present, but the large brass thrust flange has been removed from the bushing.
3 later washers are present. The clutch hub was loose.

My question is: What is the correct thickness supposed to be for the 3 thrust washer stack for proper clearance in this early transmission??

Thank you in advance.

You may be able to figure out the measurement using this info from Langs. Maybe it will help. https://www.modeltford.com/item/3320BW.aspx

As far as the correct working measurement between the drum and disc would be wouldn’t it be the same as the later transmissions used if a good top hat bushing was in it?

Depends on which clutch drive hub you have. Early vs late have different dimension from set screw to thrust face by about .015”

So are the earlier clutch drum hubs visibly different like the earlier drums are from the later ones? Are do you have to only measure to find out.

Thanks.
You steered me to that one thinner washer. Lucky, I had one. Saved me some time.
The clutch hub was an original 6 hole unit.
She went back together fine. If I had used the 3 thick washers again it would have been to tight.

The clutch pack started with 1 thick inner & ended with an inner. Didn't like that. Is that stock in an early transmission? My 14 was not that way.
I added an extra outer as the last disk. Plenty of room. A last inner disk is what wears out the drive plate holes for the 3 finger disk.
No evidence of wear in the drive plate holes.

Motor/trans appeared to be quite low milage with very little notching to the brake drum. Dressed the notches.
Transmission center shaft was dated 1-26-15. It indicated 0 - .002" after assembly. Excellent in my book. That can be a rather involved job to fix.
I did find the drive plate had a nasty warp. That's probably what wore out the 4th main. Pan to be checked next. After removing the warp with some clean up cuts, I ground the output shaft & polished. Fitted a new ball cap to the shaft.

To the best of my knowledge, you cannot go on visibility between the two. I may be wrong on that. But I’ve seen forgings of different design and some early and some late both with six holes around the perimeter. I think most of them had one hole on the perimeter for the late hubs, but I’m not sure of that. The difference between the early and late like I said was the position of the set screw to the thrust face. The early hubs were .515 inches from the center of the set screw to the thrust face and the later ones that used the three washers is .531 inches. Someone may correct me but the top hat bushing has a head that is .110 inches inches and the three washers are .126 inches. Maybe he made the washers out of scrap from somewhere else in the process and that’s why he changed the dimension. Maybe somebody else has the answer for that also because I would love to know.
To the best of my knowledge also, they carry the same part number between the two.

Why he did that? You’d have to dig deep into Henry Ford’s brain.

Thanks greenacres for the update. The reason I asked the question is that the earlier drums are visibly different than the later. I was thinking the clutch drum hub may be too.

That all sounds good dimension-ally.
The only correction would be - clutch hubs have a minimum of 2 holes in the perimeter for a puller to attach.

John- do not end with a small disc- it will put some of the driving load on the push collar and wear out the three pin holes in the driven plate.

Regarding the clutch hub and identifying the two different ones:

https://www.mtfca.com/phpBB3/viewtopic.php?f=2&t=40986

Dan McEachern wrote: ↑

Tue Jan 30, 2024 2:23 am

John- do not end with a small disc- it will put some of the driving load on the push collar and wear out the three pin holes in the driven plate.

Regarding the clutch hub and identifying the two different ones:

https://www.mtfca.com/phpBB3/viewtopic.php?f=2&t=40986

Thanks, Dan.
I did finish by adding a last large disk.
A previous "mechanic" removed the brass hat & used 3 later thick washers.(to tight)
The hub is the original early style.
I got it sorted out.

greenacres36 wrote: ↑

Mon Jan 29, 2024 10:46 am

Maybe he made the washers out of scrap from somewhere else in the process and that’s why he changed the dimension. Maybe somebody else has the answer for that also because I would love to know.
To the best of my knowledge also, they carry the same part number between the two.

Why he did that? You’d have to dig deep into Henry Ford’s brain.

The 3 equal thickness washers were made from cyanide can scrap. But that isn’t why the dimensions changed.