2 speed powerglide transmission question 2

[mc52279]

Hi all - I am swapping a 2 speed powerglide transmission in my 1964 Impala and the replacement transmission is longer than the older transmission. I want to see if it is possible to take the rear 'cone' off of the transmissions and swap them. By 'cone' I mean that there is a cone type of housing at the rear of the tranny - both trannys have the same type of cone that bolts up to the main transmission housing, only one has a longer spline than the other. I have taken the cone off to the point where the drive spline goes into the housing but am stopping here before I get more information. Thanks for your advice.

 

[Fabrico]

The "cone" is matched to the output shaft of the transmission. It's rare at best that you could change the cone without changing the shaft. Most transmissions require complete disassembly to change the output shaft.

It is remotely possible that the shaft could be cut if the remaining spline matches the original. If cutting it provides a shorter spline, then it's not a good idea. If you do cut it, make sure it has a big champher and is thoroughly deburred.

Many swaps involve having the driveshaft modified by a driveline shop. This is not an expensive procedure. Another option is having a transmission shop match things up for you, or do it your self. P/G's are just about the easiest automatic there is to work on.

 

[Greenlight]

As I recall the Powerglide transmissions come in 25.5" and 28" overall length (I may be a little off on the numbers). The rear extension housing, "rear cone", bolt pattern is the same, so yes you can bolt on the short extension housing on to any aluminum powerglide case.

There are also two different output shaft splines (one coarse spline (~14 splines???) and one fine spline (~26 splines ???).

The output shaft is permanently attached to the planetary gear set. This assembly can not be taken out without disassembling the entire transmsision.

If you just try and cut the output shaft to the shorter lenght you will run into several problems.

1 - the speedometer gear on the output shaft will be in the wrong location.

2 - you may not have enough spline remaining on the output shaft to allow the slip yoke to engage into the rear extension housing bushing.

My suggestion to you (if you must use the longer transmission) is to have the driveshaft shortened by the difference in length of the two transmissions.

 

[z06ers]

my advice to you is to contact a transmission specialist such as accurate transmission, certified transmission, or even russ moore transmission. these guys aren't even close and i can't give u advice because of propietary reasons.