Parts with new transmission mounts (400TH)?

[71CHEVYSHORTBED402]

Might be dumb questions, but I'm trying to determine which of these parts are "souvenirs" Vs what's re-used. The mount is still in good shape, but I'll replace it anyway for the restoration. Thank you.

[B. W.]

the mount is one piece

spacers & bolts don't come with the new mount

[71CHEVYSHORTBED402]

Originally Posted by B. W.

the mount is one piece

spacers & bolts don't come with the new mount

Thanks BW. Go figure I have two different bolts. One GR 5 stamped with a triangle. Might be original. The other is a pinch shorter, GR 8, and is stamped MR. GASKET.


Happen to know why spacers are used and when? The suspension was original on this truck. 2WD. Edit: Seems grade 8 is in order. The threads on the GR 5 bolt were beat up.

[Steeveedee]

Those spacers set the level of the engine in the truck, I'm guessing. I've not seen this before, but then I don't specialize in these trucks. I don't know if mine even has these. If you weren't having drive line noise, I'd put 'em back in. That amount of shim would change the angle a fair amount.

[71CHEVYSHORTBED402]

Originally Posted by Steeveedee

Those spacers set the level of the engine in the truck, I'm guessing. I've not seen this before, but then I don't specialize in these trucks. I don't know if mine even has these. If you weren't having drive line noise, I'd put 'em back in. That amount of shim would change the angle a fair amount.

Agreed. At some point I'll have the drive line professionally done, so I'll let them figure what's what. Truck is being dropped 2.5 / 4.

[Steeveedee]

It occurs to me that that beat up bolt should have been beat up before being installed, since the transmission case is aluminum and would have suffered damage before the bolt did. You might want to check the threads in the tail shaft to see if they are beat up. If it were me, and the threads in the tail shaft were damaged, I'd consider putting in a stud with something like JB Weld to keep it from stripping more. Then, just a nut on that stud. You might not have room, though, since the trans would have to lift a ways to be removed. Just something to think about.

[71CHEVYSHORTBED402]

Originally Posted by Steeveedee

It occurs to me that that beat up bolt should have been beat up before being installed, since the transmission case is aluminum and would have suffered damage before the bolt did. You might want to check the threads in the tail shaft to see if they are beat up. If it were me, and the threads in the tail shaft were damaged, I'd consider putting in a stud with something like JB Weld to keep it from stripping more. Then, just a nut on that stud. You might not have room, though, since the trans would have to lift a ways to be removed. Just something to think about.

Tail shaft bolts were like new or close. Id have to measure, but I'd say the threads are bad where it met the mount or spacers, not the transmission itself.

[Steeveedee]

Originally Posted by 71CHEVYSHORTBED402

Tail shaft bolts were like new or close. Id have to measure, but I'd say the threads are bad where it met the mount or spacers, not the transmission itself.

Good to know. If those threads are beat, the bolts may be a tad too long, allowing them to get against the spacers while the truck was in motion. How do the spacers look, in the holes? Are they marked by threads? Just something to check.

[notsolo]

My 71 Long bed 350/350 only had 1 spacer. Did the rear of your truck have any mods done to it? Are the motor mounts original? that might change how level the engine and trans sit.

[71CHEVYSHORTBED402]

Originally Posted by Steeveedee

Good to know. If those threads are beat, the bolts may be a tad too long, allowing them to get against the spacers while the truck was in motion. How do the spacers look, in the holes? Are they marked by threads? Just something to check.

Pretty (*^(*^ smart Steeveedee. I read your post and did my homework. That bolt is what I thought was (still could be) an original bolt. It's 2" from the bottom of the head. The grade 8 undamaged MR. GASKET bolt is 1.7/8".

Anyway, the damaged bolt is 1" longer than the mount and spacers, and yes it was rubbing against one of the spacers. And yes the transmission threads take approx. 7/8", so yes, the bolt is too long. They took lock washers, but the application calls for 1.7/8" bolts, IMO.

Here I was prepared to order new 2" bolts. On second thought, probably have to anyway, scarcity of 1.7/8, but that's what washers are for. Learn something new everyday, appreciate the edgeucation.

EDIT: Thought of another ?.........I wonder what's best GR 5 or GR 8, considering the transmission is just aluminum? Maybe it doesn't matter.

[Steeveedee]

Not so much smart, as having a ton of experience, not all of it in my favor.