Does a yblock with a 3 speed trans and a yblock with a 4 speed trans use same driveshaft? I found a 3 speed driveshaft and wonder if it will work with the 4 speed? Bill

 

No.
Both are different.

 

thanks----that will save me a hassle. I will keep eye on a driveshaft for a 4 speed. thanks again!!!! Bill

 

Bill, give me the application, and I'll give you all the pertinent details: length, ID color banding (if any), U-joints...etc. I need to know the year, make of 4 speed, and wheelbase.

 

N.D.---I brought a 272 yblock and 4 speed back from Connecticut,for ksmith in March. He just notified me that I could have it and the tranny .....I know it was froma 1956 FORD F600 272 2 barrel and 2 speed eaton rear. I have the frame now as that is my cummings swap truck ....I thought if I could put that into a F100 frame and hook it up,but need a driveshaft. I have an extra F600 2pc driveshaft left-over would that be usable? The new F100 is 110'' wheelbase and so nice to finally work on a F100 instead of F600S..........thanks N.D...........Bill

 

What I will need is the supposed length from the transmission to the rear axle minus the front yoke and companion flange. The wheelbase is?: short bed 110" or long bed 118" An Eaton 2 speed in an F100...that's gotta be a first!

 

Dumb question: Would this apply for my 1959 f-100 with a 292? I'm trying to find a transmission but I can only get a 4 speed instead of my 3, on the column. Will I need to grab that driveshaft off of that truck? Does it matter if it is a long or short box as well? Sorry for stealing your post.

 

If you're changing to a 4-speed then yes you'll need to grab that driveshaft as well.
It does matter if long or short box. The long box shaft will be 8" longer than the shortbed shaft.
So if you have a longbox shaft going into a shortbed truck you'll need to shorten it 8".
Just the opposite for a short shaft into a longbed, you'd need to extend it 8".

 

So since my truck is a long box and the doner is a long box it will work, but if the doner was a short box it wouldn't work right?

 

Correct.
A shortbox has a 110" wheelbase.
A longbox 118" wheelbase.

 

What is the difference in length between the 3speed and 4speed driveshaft?

 

I think the 3-speed driveshafts were all one length for both long and shortbeds, the difference was made up in the transmission tailshaft length, according to my Ford truck shop manual, it shows the 3-speed tranny with extended tailshaft but does not for the 4-speed.
So I may be wrong here, I assumed the 4-speed shaft was longer for the longbeds, 8" difference in wheelbase it has to be made up somewhere, but I have nothing to compare to so I can't be 100% sure on what I told you earlier.
I know the 3&4 speed shafts hook up to the trannys differently, the 3-speed yoke slips right into the tailshaft and the 4-speed shaft has an extension that bolts up to a flat plate coming off the back of the 4-speed with 4 bolts, therefore the 3-speed shaft won't work with the 4-speed trans and vice-versa.
Bottom line here is if you're swapping from longbed to longbed as you say, grab the trans and driveshaft together off the parts truck, you should have no problems.
While you're at it, I'd swap the steering column too so's I would'nt have a 3-speed column with a 4-speed shifter sticking through the floor, but that's just me!

 

Sorry...that's incorrect.

The 110" wheelbase trucks (2WD) have a one piece driveshaft, the 118" wheelbases have a two piece driveshaft.

Examples:

1957/60 F100 2WD 110" wheelbase ~ 3 speed manual: B7C-4605-E .. Driveshaft ~ 63 13/32" long.

1957/60 F100 2WD 118" wheelbase ~ 3 speed manual: B7C-4605-F .. Driveshaft ~ 56 1/8" long AND B6C-4816-A .. Coupling Shaft ~ 21 13/16" long.

 

Then I wonder why the extension on the 3-speed trans?
Do you know anything about that?

 

While the 3 speed manual transmissions are the same, the extension housings may be different lengths between cars and trucks. It depends upon the application. There are 3 different extension housings listed for 1957/60 F100's alone.

The driveshaft/coupling shaft info I typed above in post #13, is direct from the 1957/63 Ford Truck Parts Catalog.