904 Transmission tail shaft too long?

[Prime72]

I'm in the process of dropping my engine/trans in but the tail shaft goes about 4 inches too far passed the cross member mount where it should bolt up to. With some work, I got the block fully bolted in.

I have a 1972 small block Challenger and am trying to drop in a 318 (from a 1972 dodge truck) combined with a 1976 904 transmission. (I already changed the oil pan and pickup)

What could be causing this issue?

My research says that this should be bolting up fine. I'm not 100% sure on the year of the trans tho (the number stamped on the side of it is PK4028454 5801 3901)

I can get pics if needed, thanks a lot in advance

[blown motor]

That PK number is on the left side, correct? There will be a number on the right side that will be a digit, then a letter, then the last 6 digits of your VIN number if it's a numbers matching tranny. The first digit is the year of the car/tranny.

[burdar]

My guess is that it has something to do with the motor mounts.  Are the truck mounts different?  Maybe the motorhome 904 is a weird animal?

[Prime72]

Thanks for the replies:

Yes the PK number is on the left side, I'll have to check the right side number when I get home. That should be helpful in nailing down the year if that is the issue (the trans is not # matching). I bought a 904 torque converter and it fit well.

The truck mounts were different (much taller, different shape) but I forgot to mention that I swapped in small block car mounts.

I don't believe they put 904's into motorhomes because they're "light duty," only 727's? But I'm not sure on that.

I have 3 bolts through the block "ear tabs" to the motor mount brackets on each side, then the single nut holding the bracket to the mount, and then the single bolt through the mount to the K frame. There's only one side that the brackets could go on on the block tabs, there's really no where to make an adjustment. All 1972 318's are the same length right? I have a spare in the garage actually so I'll get the measuring tape out when I get home.

A custom plate could be made (not by me) to attach to the cross member mount to make new bolt holes farther back but I really want to figure out why this combo isn't fitting.

Thanks for any additional ideas

[burdar]

Where did I get "motorhome" from? 

I've got a 76 904 in the garage.  It looks exactly the same as my original 73. 

Do you have the motor mounts bolted infront or behind the "ears"?

What trans mount are you using?

Are you using a stock V8 K-member?

Pictures would help!

[Prime72]

No worries 

That's good info on the 904.

I believe the mounts are in front of the ears, but I know they can only go one way due to a curve in the bracket on the passenger side.

The trans mount was just what was on the 904 when I got it. Right now the trans is "bare" mount-wise and is on a jack while the cross member has the trans mount already bolted to it (1 bolt). The member has 1 bolt out of 4 in so I could swing it up and then bolt the mount the the trans, except the mounting location on the trans is too far back.

Stock V8 K member as far as I can tell.

Pics:






Left are BB brackets, I'm using the ones on the right with new rubber mounts.


Not a great pic, but you can kinda see the K frame. (Day before I bought it)

These are what I already had uploaded, I can get better pics of specific parts tonight tho if it would help.

[tactransman]

All 904's have the mount holes in the same spot on the extension housing. They even share the same mount spot as a 727. You are saying that the mount holes are 4 inches too far towards the rearend?

[burdar]

The engine brackets mount behind the ears.  Double check where you have them.  That would pull the engine/trans back too far if they were mounting in front of the ears.  Also, how do you have the trans mount oriented on the trans?

[Prime72]

All 904's have the mount holes in the same spot on the extension housing. They even share the same mount spot as a 727. You are saying that the mount holes are 4 inches too far towards the rearend?

Yep, that is what has me stumped.

The engine brackets mount behind the ears.  Double check where you have them.  That would pull the engine/trans back too far if they were mounting in front of the ears.

Thank you, I will check this out when I am home in about 4 hours. I think they may be on the wrong side, however the curve in one of the brackets wouldn't allow it to sit flush on the other side of the ear (unless I switched the driver/pass brackets). Curved bracket - pass side, straight bracket - driver side. If you refer to the picture of the brackets that I posted you may see what I mean.

Also, how do you have the trans mount oriented on the trans?

The trans mount is on the front side of the cross member, and can only be oriented one way due to two metal tabs that stick off it

[burdar]

This is a picture of a 727 but they bolt up the same way.  Double check and make sure this is how you have your trans mount and x-member bolted in.

http://www.moparaction.com/Article/PoP/II.jpg

[Prime72]

Cool, thats what it looks like, except a bit rustier.


Perspective is a little off but you can see where the cross member attaches to.

It looks like my mounts are on the wrong side tho. Gonna start on switching those around. Hopefully that'll get it where it needs to be. Thanks for the good reference pic!

[moparmaniac59]

This may sound dumb, but are you sure the tranny is a 904 & not a 727. I had a '73 Barracuda and switched from the stock A-904 transmission to a 727. The 727 was about 3 inches longer and I had to have my driveshaft cut (shortened) and balanced before I could install the transmission.


                                                                                  Matt B.

[Prime72]

This may sound dumb, but are you sure the tranny is a 904 & not a 727. I had a '73 Barracuda and switched from the stock A-904 transmission to a 727. The 727 was about 3 inches longer and I had to have my driveshaft cut (shortened) and balanced before I could install the transmission.


                                                                                  Matt B.

Yeah, the PO actually told me that it was 727 so that was the torque converter I bought, had to return it after it didn't fit and I looked up the number. 904 TC fit easily the first try.

So, I guess third times the charm cause I flipped the brackets, curved one to driver side, straight to pass side, and I ended up getting it all bolted in. Then jacked the tranny up and it lined up almost perfect.

Maybe I'll get it started this weekend??

Thanks a lot for the suggestions and then final solution burdar! Noob mistake but maybe it'll help someone out in the future.


Linin up! Not fully bolted in yet.


Driver side curved bracket. Passenger car oil pan changed last week.

New power steering pump cap was found at:
http://www.summitracing.com/parts/rnb-82581

Thanks again!

[burdar]

Glad you got it figured out. 

[moparmaniac59]

  




                                                                      Matt B.