1968ragtop

I have a th400 in my 69 cutlass parts car, I think its a long tail shaft (tail is about 9" long) Should I put this long shaft trans in my 68 convertible or look for a short shaft transmission. Can the rear shaft be replaced with a short tail shaft?? TIA

svnt442

It is a long process to change the tail shaft. The trans would have to be completely disassembled to get it out. It would be easier just to find a short tail trans and be done with it.

MDchanic

If it's already in a Cutlass, shouldn't it be a short shaft (I could be wrong here)? Or did you modify it to fit when you put it in?

- Eric

Rickman48

If the parts car has a driveshaft in it, just switch both.
[if it's a 2-dr]

1968ragtop

I'm not sure if its the long shaft. The tail shaft is about 9" long, does that sound like a long or short shaft?? The car its in is a 69 2 door cutlass and it has a driveshaft in it, so it should swap into my 68 no problem. I didn't know a long shaft would even fit in these cars. Can anyone tell me how to identify if its long or short shaft??
TIA

1968ragtop

After looking at my th400 s.p. trans.... this one is definately a long shaft.

1968ragtop

So apparently the long shaft th 400 does fit into a 2 door cutlass, so I'm looking for opinions on if this is a good idea or if it would be better to find the short shaft th 400? Is there any difference internally other than being longer??

kgenesse

No, and in fact, at work we convert them in under an hour. The one you have is a medium shaft. The longtail is 12" and only used in Cadillacs.

If it fits in your car and you have a driveshaft for it, then you should have no problems using it. Or, you can swap the output shafts and covers.

joe_padavano

Since the output shaft is the last thing out and the first thing in to the trans case, I assume that in an hour you are simply pulling all the internal parts out and putting them back in without any parts replacement other than the output shaft. I'm (unfortunately) a MIGHTASWELL guy, so if I've got the trans that far apart, I MIGHTASWELL rebuild it.

kgenesse

No, we rebuild the unit in that hour. haha

1968ragtop

Is it hard to find the short shaft tail and output shaft for these th400s?

ziff396

Really. You can properly disassemble, inspect parts, go through the valve body, replace all seals, bearings, clutches etc in 1 hour?? Along with the tail shaft?? Maybe the haha was a joke.

kgenesse

No, we do them in an hour. Assuming they are on the bench when we start. Disassembly is all done with air tools. We take everything apart and throw it in the washer for 10 minutes and that thoroughly cleans everything. The heat makes the seals easily removed, and we just pluck them off and install the new ones as we go. A TH400 shouldn't take very long for a professional rebuilder. The new stuff is what ties up the bench.

Also, if you are having a hard time finding a short tail output shaft and housing, let me know. Give me the year and spline count and I can find one for you.

1968ragtop

kgenesse... where are you located?

kgenesse

Live in Rhode Island, work in Massachusetts. It is likely that we have a short shaft and housing on the shelf at work.