We have a http://www.northerndrivetrain.com/product/SPI-2-3-10431X.html yolk for a turbo 400 but it bottoms out a solid inch or so before it should and doesn't sit flush to the tail of the transmission. Is this the wrong yolk or can you put this yolk in incorrectly or something?
The yoke should go in all the way,but not when you are putting the drive shaft in.When you hook-up the shaft to the rear,it should pull back back enough to have about 1 1/4 to 1 -1/2 inch space between the solid part of the yoke and the end of the trainy.If you mount the drive shaft and it goes all the way in,the shaft itself is too long.Bruno.
I understand but what I'm saying is that we have just the yolk right now not connected to the driveshaft. When we put it in to the tail of the transmission, it doesn't go in all the way.
YA, if that yoke has splines all thew way to the end there, I bet it won't go in all the way.. The factory had a long yoke for the 400's, it was actually used with an o-ring on the tailshaft, to provide provide a seal for the yoke. To move in an out, the yoke must be able to pass air.. so it has to be vented. This is accomplished in two ways in a 400, depending on the vintage. From the late 60's thru the 80's, a long yoke/o-ring was used.. the front two inches or so of that yoke was a smooth bore, with no splines. this allowed it to seal on the o-ring on the output shaft. There was actually a hole in the rear of the yoke, to allow it to "breath". Earlier and later 400's, and most of the aftermarket stuff I have seen, uses a shorter yoke, and has a means to pass air from the front to back, inside the yoke.. no hole in the rear of the yoke, it breathes inside the trans, and uses just the outer seal of the extension housing to seal everything up. Most likely that yoke will work fine, but your smart to test fit it, before the driveshaft is built or modified. If it has splines all the way to the end, then stick it in as far as it will go, and mark how much is sticking out with a felt tip pen, so your driveshaft builder can take that into account.
Well is it supposed to bottom out like that? After there's probably about 2" of splines in contact when the yoke is bottomed out. And I think the rule of thumb is to give it about an inch of travel from where it bottoms out so that only leaves an inch of engaged splines. That doesn't seem like enough.
