T5 Crossmember

[Jemezcrusher]

Am in the process of mocking up my 50 3100. Using a T5 tranny and replacing the original master cylinder with a power booster M/C to operate the four wheel discs. I thought I would be able to use/modify the original crossmember but after I set the new master cylinder in place, it is obvious that won't work.

Anyone have a similar set up and if so, did you fab a crossmember or was there one available from a vendor?

[Lo1dakota]

Search for my thead about my build. There's a little info and photos in there.

[nvrdone]

I've got an m21 in my "49. added power brakes under the floor. used the stock cross member mounted under the frame rails. works great. lots of clearance for the m/c

[mr48chev]

Problem is that not all Power booster installs for these trucks put the booster in the same spot. Some are up forward and some have a long push rod between the pedal and the booster to set the booster back a ways.

On the crossmember you may be able to fab your own or one of the aftermarket tube crossmembers that you might even be able to get though your local speed shop or parts house that sells speed goodies. Trans dapt shows a bunch of them .

[Lo1dakota]

So I removed the factory crossmember. I cut the flange on the factory crossmember off flush with the top. I then slid it into place under the trans. Once it was in the correct location I welded 1/4" plate to the sides of the frame with holes corresponding to the factory crossmember essentially making it removable. I think kinda had to make a hokey for my standards mount from the trans down to the crossmember utilizing a factory T5 tailshaft mount. I'm sure this is confusing so I'll just post the photos.

[Hampshire]

I like Lo1dakota's setup...

Below is mine in process with a Tremec & fabbed crossmember. 4Wh discs & frame mtd power booster. Have a better pic somewhere with exhaust & driveshaft (it was finished a couple seasons ago). Plently room for the exhaust.

[dsraven]

I like lo1dakota style which looks like a factory member. could the frame pieces be bolted on instead of welding to reduce frame stresses? does it become a "high centred" restriction over speed bumps etc? a brace from the top rail would also add strength between the upper and lower areas. nothing wrong with the square tube idea either. both function well and leave room for other stuff like exhaust. remember to leave room between the brake booster or even add a heat shield to protect the booster and brake fluid in the steel lines.

[Lo1dakota]

Originally Posted by dsraven

I like lo1dakota style which looks like a factory member. could the frame pieces be bolted on instead of welding to reduce frame stresses? does it become a "high centred" restriction over speed bumps etc? a brace from the top rail would also add strength between the upper and lower areas. nothing wrong with the square tube idea either. both function well and leave room for other stuff like exhaust. remember to leave room between the brake booster or even add a heat shield to protect the booster and brake fluid in the steel lines.

You could bolt it but it's not really that much weld. Your choice. No it doesn't get high centered. And I'm fairly low.

[Jemezcrusher]

I was under there looking tonight. I have some 1.25 PVC that I could fashion a crossmember using some 45 degree fittings and cut and fit until correct to use as a pattern. Would like to have it attach inside the frame rail, drop down to pick up the mount, then back up on the other side. My 6cyl dual exhaust runs under the crossmember so should be able to fit it between the exhaust and trans/ master cylinder

Hampshire, is that a universal poly mount you used?

[nvrdone]

I used lo1dakota's idea. just made up plates that bolt to original mounting holes & mounted the factory cross member under the frame. so far I haven't high centered on it & the exhaust has plenty of clearance. im happy with it

[Lo1dakota]

Glad my idea has helped. I drug it for the first time today and just barely. Like I've said I've got a 3" drop axle and 3" lowering leafs. In the back it's 3"leafs and 2" blocks. I went out of a drive way today that hade at least 12" drop within 2 feet so steep. It just barely touched it. And made my butt pucker because I just painted the frame lol

[Gippetto]

I recall a debate in this forum a few years ago between guys not using a cross member with a T5 and those who felt it was necessary. I am surprised no one stepped up and says you don't need it and to save your time. I believe it was a 235 /T5 combo that was disputed. Any votes for no cross member at tranny?

[iowaboynca]

For those of you looking for a x-member, this was posted on hotrod's website today.

Don't know the shop, don't know the cost but looks like an interesting design.

http://www.hotrod.com/articles/jbc-9...n-crossmember/

[solidaxel]

Originally Posted by Gippetto

I recall a debate in this forum a few years ago between guys not using a cross member with a T5 and those who felt it was necessary. I am surprised no one stepped up and says you don't need it and to save your time. I believe it was a 235 /T5 combo that was disputed. Any votes for no cross member at tranny?

I think the cast iron bell housing has alot to do with holding the transmission.
I have a Tremac TKO 600 mounted to a stock cast iron BH in my 55 GMC and I have "used" it hard for the last 70,000 miles and all is well!
The ZZ4 has side motor mounts and the BH is mounted with stock two piece rubber mounts

[Jemezcrusher]

You would think that if the original needed a crossmember, so would any replacement. I am not going all out on one, just something to solidify the tail housing.

May not be necessary, but will make me feel better