Welded or not? 72 transmission suport

[Calvin C.]

OK I have heard it two ways now, which is it? I have been told that if the crossmember is welded it is an automatic, if the member is bolted it is a 4 speed, and I have heard it the other way. I have also been told that it is welded for the 4 speed because you can remove the unit with the cross member in place, while with the auto you have to remove the member. So what is the real answer.

thanks
cal

[Harmon C.]

Re: Welded or not? 72 transmission suport

4-Speed=Welded Automatic=Bolted

[Calvin C.]

Thanks once and forall,

Thanks! That's two NCRS guys, that makes it final.

[Joe L.]

Re: Thanks once and forall,

Cal-----

I agree; it's as Lyle mentioned. However, the bolted transmission crossmember can be used with cars with manual transmission. From 1978 onward, both manual and automatic transmissions used a bolted crossmember. Also, many SERVICE frames for 68-77 Corvettes sold after the mid 80s were of the bolted crossmember variety regardless of transmission application.

A welded crossmember cannot be used for any 68-82 automatic transmission application UNLESS one plans to ALWAYS remove the transmission as an assembly with the engine.

[Chas Henderson #28127]

How do they remove the tranny ina 4-speed?

at a tranny shop? I cant believe they would pull the engine to do it in a 68-77 car. And if so, that seems like a poor design when they had the crossmember of the same design bolted in for an automatic. Why not have all crosmembers bolt in for thoes years?

Chasman

[Patrick H.]

Re: How do they remove the tranny ina 4-speed?

It's not horribly tough to remove the driveshaft and shift linkage, then back the 4 speed up until it's as far back as you can, and drop the front down and out. I've done a couple of them. An automatic is about 50% larger than a 4 speed in every dimension except length, so I'm not surprised it can't be done.

Patrick

[Joe L.]

Re: How do they remove the tranny ina 4-speed?

Chasman------

A 1968-77 Corvette with manual transmission can be removed from under the car even though the crossmember is welded-in. It's the automatic transmission cars that cannot have the transmission removed seperately if someone installs a welded-in crossmember frame to an automatic-equipped car. No cars with automatics EVER were factory-equipped with a welded-in crossmember frame. However, when frames are replaced or if a manual trans cars is converted to automatic, the problem can occur.

[mike cobine]

Poor Design - Corvette? You are kidding

Try the '63 to '67 frame. The change came in '68 because the Turbohydramatic 400 would not work in the existing frame setup for service.

They saved money by not having a extra bolts and welded nuts with a bolt-in crossmember on all the others.

A list of things designed better that would have improved our lives greatly could be very, very long here.