700r4 snug to trans hump

[triophan]

just as the title says, my trans tunnel seems a little snug and I can hear it a little too clearly running down the road.

Could my crossmember push it up? could the driveline angles be off?

THANKS
-david

[bigblock73]

Mine is close too, I would say less than an inch. I am assuming your truck is a 2wd, low hump?

Mine is not running yet, but I was wondering the same thing.

[triophan]

2wd, low hump.
its RIGHT there too... If I brake hard or do anything else that I know causes a little flex in the drive, I hear it.
Higer speeds too.

Easiest solution would be add an inch to either side of the tunnel??? effectively raising it an inch-ish?

[S10Fan]

I have roughly 2" clearance with mine, 454-700R. My transmission support is a hybrid though, altered version taken from a 67-72 series C-10.

[Tx Firefighter]

You haven't mentioned your cab mounts. Old cab mounts will sag like grandma's you know whats. There might be an inch of clearance missing right there.

[bigblock73]

Kevin, mine has all new mounts. I think it is simply the 700 swap, its a longer transmission and the case girth seems to be larger than that of the old th350.

David, I think the easiest aproach would be to section the trans crossmember an inch or so. I may do this once I get the truck on the road and see how it responds.

[Tx Firefighter]

Jeff, do you think the earlier cabs are snugger in the floor tunnel area ? Did GM make it more roomy when they went to the 700R4 in the later years ?

I have done extensive swapping of TH350s and 700R4s, but only on 67-72 trucks and 82 and newer square bodies. I have never swapped one into a 73-81 model.

[bigblock73]

Kevin, I am not sure to be honest. I know the trans crossmembers changed slightly thruought the years, perhaps that is how they compensated for the larger/longer transmission.

[bigblock73]

Kevin, went and looked at your trans hump thread..the tunnel in your 85 looks just like the one in my 73 for what it is worth. I'll try to find the pic I took of my transmission/tunnel, or take a new one if I can't locate it, and post it here for you guys to see.

[johnnypop]

When we installed the 700 in my 4x4 we had to drop the trans crossmember about an inch to get some extra clearance without lifting the cab. New cab bushings were installed as well. Not sure if that is an option with a two wheel drive, but for me it actually made the driveline angle to the rear end better.

[Toxic Redline]

If you don't like the noise try putting some noise barrier stuff on the floor maybee....

[triophan]

^thats like, "if you don't like rust, just paint it."

I was thinking it could have something to do with the crossmember, I'll get out there this weekend and play with it.

All new cab mount bushings BTW, and new trans mount bushing. I am almost to where I can get into the engine bay... I'm going to double check and make sure everything's in line. if something is off fractions, seems like somewhere down the line the issue could be compunded. May hit the junkyard and get another crossmember to section per Jeffs advice.

We'll see...

[Toxic Redline]

Or you could put in a kicking system and not even hear your self thinkg