I have started work on a 1953 pickup that will be updated with a 5.0L engine, fatman front suspension, 9-inch rear, AOD transmission and disk brakes. I want to keep the body as original as possible because it sports a beautiful, honest 60 year old faded patina. My question is thus: Will I have to remove the original transmission crossmember? I would like to keep it in place if possible.

 

Pretty unlikely. The stock trans is very short and modern transmissions are much longer. The only way to be sure is to take some measurements. Assuming the crank pulley on the new engine remains in roughly the same location as the original engine measuring from the pulley to the trans mount should give you a good idea of where the new trans mount will be in relation to the original.

 

Thanks for the reply Mike! Your reply reminded me that I need to further explain my question. I know that I will have to install another trans crossmember for the engine/trans combo that i mentioned. I just hope to keep the original crossmember, which happens to be adjacent to the front cab mounts, and thus maintain frame stiffness.....that's the plan anyway.
Again, thanks for the reply!!

 

I don't think the AOD will fit. The pan will likely interfere with the stock X member. A T5 might, just might, fit over the stock X member. There are others here running AOD's and T5's that will be able to tell you what it will take to make it work.

 

The cross member should stay to keep the frame rails from twisting but modified so it can be removed for transmission servicing.

 

As John has said, the crossmember is a necessary structural support (I'll save you the engineering analysis I posted some time ago) but it will need to be modified to make it removable. Here is a pic of my 56 chassis with a 302/AOD combo. The AOD will sit in the frame just fine but once the cab is in place it is virtually impossible to pull the trans without modding the crossmember.

 

CharlieLed/56panelford:
How did you make the original crossmember removable? On the surface, it would seem the rivets should be removed and the crossmember bolted into place. Are my assumptions correct?
BTW, good looking frame CharlieLed with the exact setup I want when my 53 frame work is done.
Lastly, thanks to all the help and replies and the effort you take to make them.

 

Not the best pictures unfortunately but I cut the cross member where it narrowed. I was going to reuse what I cut out but it hung down lower than my new front cross member so I welded up a new piece from 1-1/2" square tubing and is now the same level as the front member. Four bolts hold it in place.

 

56fordpanel:
Looks good and I like the idea. Your pictures are fine. I will save them as reference as I fabricate my crossmember.

 

There are various ways to go about it, John's solution is one of the better that I have seen. Take a look at the attached drawing/force vector analysis and hopefully it will give you a better feel for why this crossmember is so important. Whatever way you choose, make sure you weld a couple of cross supports on the top and bottom of the frame before you cut the crossmember. Most of these frames are under some amount of tension so when the OEM crossmember is cut the frame will want to move.

 

CharlieLed:
Yep, that's what I'm talking about. The drawing represents what I expected to be true with the the front cab mounting on the supports cantilevered outboard of the frame rails. Good stuff and the advice is loud and clear.
Thanks to all you folks for going the extra mile to explain, sketch and photograph the problem and solution.