How to tell if a 727 has a lock up converter? I read on Allpar.com that in 1978 Dodge started making lock up converters for the 727. That is something I would like to have in my 76 W100. Im having some leaking problems with my 727, I have my 727 out of the truck right now and am thinking about having it rebuild. I know of a 78 Powerwagon parts truck that has a 727 in it. On Allpar it says that you can identify a lockup 727 because it has about 5/8 of a inch of the end of the smaller input shaft machined smooth. If the splines go out to the end of the shaft , except for about 1/8 inch bevel, then it is a non lockup 727. Im not sure what shaft they are talking about. Does anybody know what shaft they are talking about?

 

That sounds a bought right. Also the end of the main shaft is drilled through on lockup for an oil passage

 

Lockup input shaft


Non-Lockup input shaft

 

That is what I needed, thankyou. But how do I tell if a truck has it in it, without taking the tranny out?

 

The only way is with how the tranny shifts. In 3rd gear, you'll feel the tranny drop another 200-300 RPM. The only sure fire way is to pull the tranny.

 

Someone told me that only 2 wheel drive trucks got the lockup, why would they not put the lockup in the 4x4s?

 

That is not true as the only difference between the 2wd and 4wd trannies are the tail shaft housings. Depending on when Dodge introduced the lockup 727, you may or may not have one. If they introduced it in 1978 as mentioned before, then chances are fairly good that you do not have a lockup unit (unless someone swapped out the original tranny for a later model unit).

The Jeep J-series trucks also used the 727 tranny behind the AMC inline 6 and V8 motors and some were lockup. I know this as I pulled a 727 lockup from a 1987 J10 with an inline 6 and it was 4wd.

 

Thankyou, mine is a non lockup tranny, I am going to have mine rebuilt but if I can find a lockup tranny, Ill have that one rebuilt and I will put that one in my truck.