Hey there peeps - I've got a tranny question or two for the masses regarding swapping hardware back and forth from a 618 to a 518. Dug through many of the related threads but not sure I found what I'm after.

For background, I did a 203/205 doubler gig and bolted it to the back of my 6bt/518 combo. To mate the 203 I drilled the 203's front face to match the 518's tail, but that wasn't the sticky part. The part I didn't like was the 203 only had 3/4" of spline engagement from the 518's output. Granted the 518 is supposed to have either a 241 or a 205 (with the coupler), but I needed to work in a 203. So, to get more spline engagement between the 203 and 518 I stuffed two 1-inch spacers and a 23/23 stub shaft from A.A. inbetween them, and with that setup I got about 1-1/4" of spline both ways - which I feel is plenty.

But, I don't 'like' the spacers - I mean yah they work and nothing leaks, but I'm not 100% convinced the doubler combo is mated perfectly 'flat' to the 518's back side, and I'm just waiting for the 518 to rotate adversly against the 203, bust a bunch of stuff and make a big ole mess. I'd reallyreallyreally like to find a way to get more spline engagement between the 518 and the 203 without the spacers.

The problem...is the 518's output shaft, or rather not enough of it. From everything I've found, the output shaft on all 518's is recessed about 1/4" inside the tail flange. But, if I understand right, I think the 618's have about 1/4" of output shaft protruding past the tail flange.
My first question is, is that accurate? And my second question is, can a 618 OD unit bolt up or be modified to bolt up to a 518 main case, or can a 618 tailshaft be installed where the 518's is?

Another piece of info is all of this is going in a 78 Power Wagon named 'Bud', and believe it or not I do not want or need the lock-up function. I have several reasons why I don't want the lock-up, but if I did I'd simply go with a 47. I have a great pressure switch system to control the od on the 518 and I do not want more hassle for controlling lock-up nor do I want to pay more for another converter.

But, if I can get a bit longer tailshaft to stick out the back end of my 518, life would be golden - This is my mission.

Any thoughts on how to do that would be much appreciated.

- Sam
Falcon, Colorado

 

Does the 47's output shaft stick out past the tail flange?, by ~ 1/4"?

So if I did a newer od unit, I could gain my precious spline length, but I'll lose the function that operates my pressure switch that tells the od what to do with itself, that pretty much it?

If I lose the governor pressure function, any ideas on what else could I use to control the od? Maybe it's time to just do a simple on-off switch....that'd be pretty simple. A bit more 'manual' than I'd prefer but considering the truck this is going in...well it's not gonna be a daily-driver. hmmm....

 

[QUOTE='Mad Max';2774960]Does the 47's output shaft stick out past the tail flange?, by ~ 1/4"?[QUOTE]

Yes it does.

 

Also if you loose the governor pressure function you will need a manual valve body as there will be no more automatic shifting.