transmission crossmember

[Mikedub82]

I'm just about finished z'ing my frame 2.5 inches and 2.5 in drop spindles with bags. I was looking for some advice on the transmission crossmember/support. How would I raise this for the 3 speed manual trans. It will not let the truck lay all the way out. Pics would help a lot. I am trying to keep the 3 on the tree.
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[smashingchuck]

I've got the stock "double hump" trans crossmember and I just counter sunk the bolts and and used tapered hex heads.

[NZSquare]

I made a new one, took a couple of hours and gave me another 2 inches or so of breathing room underneath.

Here it is installed when I first made it with a T350



Then I just had to remake the mount when I switched trannys

[N2TRUX]

Originally Posted by NZSquare

I made a new one...

Same here...

[smashingchuck]

If you do plan on making a new one be sure to tie the frame together top and bottom you would be surprised how much that trans crossmember holds everything together.

[SBTork]

Originally Posted by smashingchuck

If you do plan on making a new one be sure to tie the frame together top and bottom you would be surprised how much that trans crossmember holds everything together.

not that I am doubting you at all, what is the basis for this? I am just curious because my plan is just for a basic one to run between the frame, not tied to the top or bottom.

[Shane]

Originally Posted by SBTork

not that I am doubting you at all, what is the basis for this? I am just curious because my plan is just for a basic one to run between the frame, not tied to the top or bottom.

several of the aftermarket transmission crossmembers bolt ONLY on the bottom of the frame ... you'll be fine ...

[smashingchuck]

Originally Posted by SBTork

not that I am doubting you at all, what is the basis for this? I am just curious because my plan is just for a basic one to run between the frame, not tied to the top or bottom.

The frame rails tends to want to deform when you remove the trans crossmember like this \ / .

[N2TRUX]

Originally Posted by smashingchuck

The frame rails tends to want to deform when you remove the trans crossmember like this \ / .

Very true. So much so that it sometimes requires brute force to reinstall the stock crossmember.

[NZSquare]

I have read on here before that some feel the need to tie the frame rails together top and bottom, I measured mine (cab on, fully assembled) with the stock crossmember in and out and got no deflection.

I realise these frames have a huge amount of flex in them, I just dont think the tranny member is the source of the issue, but it all helps. Im not running big HP though. So I went the way of the Porterbuilt and SD ones (tranny members).

[SCOTI]

Originally Posted by NZSquare

I have read on here before that some feel the need to tie the frame rails together top and bottom, I measured mine (cab on, fully assembled) with the stock crossmember in and out and got no deflection.

I realise these frames have a huge amount of flex in them, I just dont think the tranny member is the source of the issue, but it all helps. Im not running big HP though. So I went the way of the Porterbuilt and SD ones (tranny members).

I have the PB style trans x-members but still used a different part that secures the top & bottom rails as part of the structure.

Both types will work, but securing the top & bottom is best.

[N2TRUX]

Originally Posted by NZSquare

I have read on here before that some feel the need to tie the frame rails together top and bottom, I measured mine (cab on, fully assembled) with the stock crossmember in and out and got no deflection.

It might not be enough to cause concern, but it is there. On my 77 when it still had the stock crossmember we pulled it for some work. I had to use a prybar and BFH to get it back in place. Trust me, the frame does flex there.