(bigblock73) Your tranny height?

[swervin ervin]

Jeff,

I think I've found out why your tranny sits to high or up against the floorboard. I bought a crossmember like your yours from Jeremy. Well I was out a little bit ago test fitting everything after I ripped out my old exhaust. I had the tranny jacked up about 1/4" between the mount and crossmember to get my stock crossmember out. Well I stick the new (to me) mount in there and it won't go. I would have to jack the tranny up at least another 1/2".

So, I stick my stock crossmember back in there and put the new one beside it. I lay a straight edge across the bottom of the frame rails and measure the distance to the top of the crossmember where the mount bolts to. My stock crossmember that came stock with a 700R4 was 1-5/8", and the one like yours was 2-3/8". This is 3/4" higher. Just for giggles, I see how high I would have to go to get the mount on the crossmember. It was almost up against the floorboard.

The thickness of my Energy Suspension mount is 2".

My question is what can be done to solve this. Is there another year mount that's 3/4" thinner which would make it around 1-1/4". Do you have to get different mounts according to what tranny you have? I'm guessing the bolt pattern on the tranny is different for different automatics. I checked some online sites and they list different part numbers for different trannys. I'm guessing this has something to do with it being a 700R4 and the dual hump crossmembers were made for TH350's and TH400's.

[MylilBowTie]

I know my cab floor and transmission space isn't all that much either. I put a th400 in, energy suspension mount, and double hump crossmember. Not sure exactly how much but I do know its a very small amount.

[bigblock73]

Mike, You are now in the same boat as me. My next step is to look at different trans mounts. I believe all GM auto trans (350,700,200,700) use the same mounts...or at least the bolt pattern is the same. I am hoping to find a different application where the bushing is shorter (maybe a Monte, GP, Impala, etc..).

I have not messes with it lately, been more tied up on the interior as of late. Please please let me know if you find something out before I do. If I figure it out, I will let you know right away.

[swervin ervin]

I checked the mount in my 79, which came with a TH400. It is maybe 1/4" or so thinner. I know Energy Suspension's tranny mount is listed to fit from the 60's up to 98 or something like that. My mount came with a metal spacer to go between the mount and tranny. Leaving this out will bring mine down to right around 1-5/8" or so.

Anyway, I just came in from working with it some more. I can leave the metal spacer off the mount and it's almost the same clearance and height. Maybe 1/4" lower with my stock crossmember using the spacer the way I had it. Seems like I remember Energy Suspension saying to use this spacer plate if your tranny was a 700R4, or of a certain year. I'm guessing and trying to remember that it had something to do with the way the crossmember is made. Anyway, 1/4" is nothing to worry about for me.

On to my next problem now. With the mount bolted to the tranny and crossmember, and the crossmember square, none of the frame mounting holes will line up. The way my stock crossmember is, only the passenger side had the extra brace on it. The drivers side wrapped under and around the outside the frame because of the cat needing to go over the crossmember. Anyway, if I put the brace on the crossmember and put it in the stock frame bolts coming through the top of the frame, it throws the crossmember out of square. Looks like I'll have to jack up the cab and drill new holes, since you can't get the bolts out of the frame with it down on the body mounts. The drivers side don't even have holes for the brace to begin with.

Looks like I can make it fit, but damn, it's going to be a lot of fricking work. Of course this fits right into every thing I do. Nothing can be simple with me.

[bigblock73]

Originally Posted by swervin ervin

Looks like I'll have to jack up the cab and drill new holes, since you can't get the bolts out of the frame with it down on the body mounts. The drivers side don't even have holes for the brace to begin with.

Looks like I can make it fit, but damn, it's going to be a lot of fricking work. Of course this fits right into every thing I do. Nothing can be simple with me.

Sounds like it is time to do a "body-off" Mike.

So how much clearance do you have between the cab abd trans with your new crossmember installed...with the spacer removed.

[N2TRUX]

Mike I read and re-read your post but I'm still not certain about something. Did you take the tranny mount off the tranny? If so, did you put it back the same way?
The reason I ask is recently I dropped the X-member on my 77 to replace the mounting bolts that had fallen out. While it was apart I cleaned and painted everything so it was the next night before I put it all back together.

I couldn't remember which way to tranny mount went and put it on the way I "thought" it should go. When I tried to mount the X-member I lined up one side and started all the bolts. When I went to the other side, the holes wouldn't line up in the frame.

It turns out I had installed the tranny mount backwards. The bolt holes are offset just enough to make a difference. When I flipped it around everything went back together like it should. This may not be your problem but it sounds similiar.....

[swervin ervin]

Jeff,

with the new crossmember installed and the metal plate spacer not used, right at the very back of the tranny where the tail shaft meets the case, I have around 3/4".

Ken,

The mount I have is in the center. It didn't matter which way I installed it. I installed everything this way, and that way, rotated the crossmember around, but it still didn't matter.

What I did, was to hook up the passenger side, brace and all. I measured this side from a point toward the rear. Then I measured the drivers side from the same place to square it up. With it square, I had to redrill the mount bolt holes in the crossmember 1/2" toward the front. So now, it has two slotted bolt holes about 1" long, front to back. I also had to drill new holes in the frame for the crossmember itself.

It was a tough job, but it's in and looks good.

Now I'm waiting for my exhaust system to get here.

Mike

[N2TRUX]

Originally Posted by swervin ervin

....
The mount I have is in the center. It didn't matter which way I installed it. I installed everything this way, and that way, rotated the crossmember around, but it still didn't matter....

Cool! The stock mount "looks' like it will go either way too. It won't.... .

[1FaastC10]

geez Mike, you dont waste any time putting stuff togther do you?

i just got home from a mud bog, and happened to see this post. i went out and measured 4 mounts i have. the stock mount, a stock replacement (single bolt, which is what was stock in my 86) one from a '77 C20 w/TH400 (2 bolt style, the actual one i had used with this crossmember, and an Energy Suspension poly mount, all came in at 2". as for the mount bolts not lining up with the ones in the crossmember, are the bolt holes on the trans side of the mount slotted by chance? 2 of the 4 i have are, not trying to insult your intelligence here, but did you tighten the mount to the trans before attempting to install the crossmember? when i installed it i started all of the bolts, and then tightened them. somehow i did get 2 of the factory crossmember bolt holes to work, the other 2 would have had to have been drilled. since i havent even put 500 miles on this truck since i bought it, and even less than that with the double hump installed, i never got around to it. i never installed the upper braces either. my 79 SWB C10 frame was drilled for everything though, hence the orange paint.

[swervin ervin]

Jeremy,

no I didn't tighten the bolts anywhere putting it in, trying to get something to line up. My Energy Suspension mount is slotted from side to side, but not front to rear. Even then, when it's fastened to the tranny, it won't move since both bolts end up being all the way to the inside of the slots.

Although I've never tried it, seen plenty of times where folks say when the put a 700R4 in place of a 350 all they needed to do was drill 2 holes. Well let me tell ya, going from a stock over and under, single hump crossmember to a double hump, nothing lined up.

I got everything in and all holes drilled, etc. Now I'm going to pull it back out and sandblast it and get it painted up pretty.

[SanitysBane]

were do u get this double hump cross memeber?

[swervin ervin]

Originally Posted by SanitysBane

were do u get this double hump cross memeber?

Here is a pic of bigblock73's. I'm not exactly sure what years came with these things. Only thing I can figure out is they came in pre catalytic converter trucks.

Mike

[SanitysBane]

interesting, not really seeing any differnce between that one and my '83 xpt for the diagonal brace on the drivers side...i just ran my over it on the drivers side and under on the other due to the way the engine flexes when u give it gas(pulls up on drivers side) all i did was get 2 3inch turn downs from autozone and welded them together to make a step up(welded the endds together), and that is one very nice looking truck.

david, but y'all can call me bo jangles,