Transmission Park rod identification

[gasoline_24]

Below are several pics of the park rod out of my existing transmission that was rebuilt by a local transmission shop. 

I was having problems getting the car out of park.  I would have to physically rock the car before it would come out of park.  I tried all of the shift linkage adjustments, but nothing would work so I pulled the tranny apart to see what was wrong. 

The top one that was in my tranny which is out of a 1967 - 68 383 car had several significant wear marks with some fairly serious sharp edges.  The second one is out of a 68 440 transmission I just found.  They are significantly different. 

I believe the second one is correct and out of a 727, but I suspect that the first one is a 904 park rod.  I am not sure who put it in, the previous owner or the transmission shop.  I have measured them per the shop manual and it appears this is correct, but was hoping someone with more experience could help me out on this one.  I have also attached the photo from the FSM.

[gasoline_24]

and the final pics

[RD]

bingo.. saw the first pic and said to myself they put in the wrong parking rod.  i bet they just replaced the VB with one they had already overhauled to avoid having to service your original one.  Without checking out my manuals, I know for a fact the 904 and 727 VB's are different in regards to their separator plates (separates the upper and lower half of the VB). 


How this, or even if it will, may affect operation is negligible i believe.  I will need to look at my books to be sure. It has been a long time since I have overhauled a 904

Check the casting date on the VB can be found where the red circle is on the bottom, or on the top (see second pic):

[gasoline_24]

Thanks RD....I was hoping it was something that easy.  It was a pain to pull it apart, but it is an easy fix.  Is the VB you posted a 904 or 727?  Do you know what the part number should be for a 727 VB for a 67, 68 or 69 727?

[RD]

Thanks RD....I was hoping it was something that easy.  It was a pain to pull it apart, but it is an easy fix.  Is the VB you posted a 904 or 727?  Do you know what the part number should be for a 727 VB for a 67, 68 or 69 727?

the top VB is a MVB from turbo action, so I am not sure what it came out of... I just took the pic to show you where you may find the date codes.  The bottom pic I found on the internet for the same reason.

If I got time tomorrow (or if John Kunkel doesnt post first ) I will do some research and get back with you on the differences.

[RD]

did the research.. there is no difference between a 727 and 904 VB except for /6 applications.  The /6 applications (up to 73 anyway) did not have a limit valve.  A limit valve "... determines the maximum speed at which a 3-2 part throttle kickdown can be made" (73 Chassis Service Manual).  It is engaged during a full and part throttle kickdown.

Why /6 VB's dont have them?  Well, I am assuming it is due to the lack of HP/Torque the engines had.  Low numbers on their end did not substantiate the need to limit the kickdown process. (John.. if you could elaborate, that would be nice as I am not finding anything on this in my books).

see circle area for picture of limit valve in the first pic (727 VB) and the second is showing it as a 904 w/o the limit valve:

[John_Kunkel]

There is a difference in 904/727 valve bodies as far as interchange goes, the difference is most apparent in the rear center attach bolt hole. The transfer plate casting has a slotted hole, the steel separator plate for the 904 has the hole at one end of the slot the steel plate for the 727 has the hole at the opposite end. Aftermarket separator plates have a slotted hole so they'll work on either one.

[John_Kunkel]

The park rods, bottom is 727.

[gasoline_24]

Thanks RD and John.  I would think for the $500 plus parts I paid to have this rebuilt they would have caught this.  Oh well, I now know more about the inner workings of a 727.  The positive note on all of this is I was able to find a 2892093 transmission for my car which is date coded within 8 weeks prior to the build date of my car.  It has been here in my hometown right under my nose and just traded some other parts for it.  What are the odds?

[RD]

Thanks RD and John.  I would think for the $500 plus parts I paid to have this rebuilt they would have caught this.  Oh well, I now know more about the inner workings of a 727.  The positive note on all of this is I was able to find a 2892093 transmission for my car which is date coded within 8 weeks prior to the build date of my car.  It has been here in my hometown right under my nose and just traded some other parts for it.  What are the odds?

awesome did you see if the tailshaft housing matched?  the 12 blocks on the end of the housing are considered the "months" and any dots you have in the blocks (count them) will be the month in which the housings were cast (if they are indeed a match).

[gasoline_24]

I didn't check that, but I will take a look tonight when I get home.  Thanks for the info.