Input shaft on 4 speed too long

[NZ 70 RR]

Took old 4 speed out and tried for hours to get replacement one in, was always 25mm ( 1") gap between housing and 4 speed casing. Finally took it out and used a ruler only to find the input shaft was 25mm longer on replacement one. Looks like the gearbox that came out has had its shaft shortened.
What are my options please.

 

[R/T Boy 67]

It seems your crankshaft is not drilled for a pilot bushing. If there is a pilot bearing in the torque converter pilot area of the crankshaft, then you are good to go, but you will have to trim back the trans input shaft same as the old one. Just make sure there is a pilot bearing in there.

 

[moparnation74]

Cut the input shaft

 

[Charger Dana]

I had to cut my input shaft because the cranks in automatic blocks are shallower than manual blocks. I have a 4 sp, but auto block. I recommend tapering the shaft a little after its cut (I didn’t).

Related info, including required pilot bearing:
https://www.forabodiesonly.com/mopar/threads/pilot-bushing-for-4-speed-swap.365670/

 

[5.7 hemi]

It’s not the block, it’s the crank, some are drilled for the 4 speed, some are not.

 

[flyingfarley]

Just ran into the same problem on my 65 Coronet...replaced the 727 auto with a 4-speed. Crankshaft was not drilled for a standard trans...use the big pilot bearing in the converter area at the end of the driveshaft, cut and tapered the input shaft...and i was out crusin with the four speed....
Good luck......

 

[65 Coronet]

Just ran into the same problem on my 65 Coronet...replaced the 727 auto with a 4-speed. Crankshaft was not drilled for a standard trans...use the big pilot bearing in the converter area at the end of the driveshaft, cut and tapered the input shaft...and i was out crusin with the four speed....
Good luck......

Had the same issue, cut and tapered and had no issues!

 

[Daves69]

What I found on a '68 440 auto crank and uncut 4 speed input if it helps...……..

Some info that may help here (2/3rds down the page) for going with a bearing in the crank register...
https://www.bigblockdart.com/techpages/4sptech.shtml

 

[NZ 70 RR]

Wow , brilliant replies, thanks heaps.
The reason I took the gearbox out was because I did a stupid thing, I had loosened the large bolt below the natural safety switch and had caused the ball bearing the sits on the reverse finger to drop into the gearbox. The box was also hitting the back of the 4 speed hump in 2nd gear because the body guy had re-welded the hump slightly forward. And I had brought a re-build kit for the box.
When I picked up another gearbox that originally came out of a RR I thought do a straight swap.
I have removed the gearbox cover and fixed the ball bearing, I have also used a panel hammer on the hump to make more room and have got a shorter adjustment bolt to got into one end of the shifter.
I have a 440 that I want to put in so will wait a couple of months and put the replacement gearbox in with that after mocking it up to make sure it fits. Fingers crossed I will be driving the RR later today.

Thanks again
Tony