HELP! - Mating tub to chassis - TC high/low shaft is hitting bottom of the tub

[Steve Abbott]

I need some quick help. I'm finally mating the tub and chassis on my '65 after about 5 years of being disassembled. My 40 had an old worn out SBC and AT mated to a 3 speed TC when I bought it. I have since replaced the SBC with a fresh '78 2F with 4 speed trans and 4 speed TC. I am using an Energy Suspension body mount kit.

I noticed as I was installing the body mount kit that the tub wasn't fully resting on the frame up front. I quickly realized that the TC high/low actuator shaft was hitting the cross brace on the bottom of the tub. I am completely stumped as to what the issue is. I assume it has to do with the motor & transmission mounts not allowing the TC to sit low enough to clear the tub. I did have to source the 2 front motor mount brackets since mounts for the SBC had been utilized as well as all frame brackets. Mount insulators are aftermarket from SOR. Is it possible the trans mount brackets are the wrong ones, causing the trans to sit too high? Also the clutch arm is hitting the tub as well. I assume it should be below that cross brace that it's hitting. Any other ideas as to what the issue is? Here are several pictures showing my clearance issue and the motor mounts.

 

[brian]

put a 0.75 or 1'' body lift on it.....you'll find that the trans cover doesnt clean the transmission as well.

 

[Skreddy]

The 4 speed tunnels are taller than the old 3 speed tunnels, as well as slight floor differences. My guess is that’s what you’re running into.

Can you shim up the front motor mounts 1/4-1/2”? May be enough. You’ll need to shim your radiator up or at least slot the fan shroud mounts and slide it up to center the fan blade in the shroud.

 

[Steve Abbott]

put a 0.75 or 1'' body lift on it.....you'll find that the trans cover doesnt clean the transmission as well.

Yeah, I knew about the trans tunnel, but was unaware that the TC would be an issue.

 

[Steve Abbott]

The 4 speed tunnels are taller than the old 3 speed tunnels, as well as slight floor differences. My guess is that’s what you’re running into.

Can you shim up the front motor mounts 1/4-1/2”? May be enough. You’ll need to shim your radiator up or at least slot the fan shroud mounts and slide it up to center the fan blade in the shroud.

I was wondering about that. Not sure if it will create other issues in the process. The other possibility would be to shave some meat off the upper insulators in the rear, or maybe a combination of both???

 

[Steve Abbott]

It looks like I can buy additional Energy Suspension polyurethane pads that are 7/16" thick and stack them. They also have some that are 15/16" thick that I could use rather than stacking two together. Other than needing longer bolts and probably needing to shim the radiator, are there any other things to consider?

 

[pb4ugo]

Steering box and column rag joint alignment.

 

[Living in the Past]

Steering box and column rag joint alignment.

Unless it's been replaced the steering has a solid shaft all the way to the steering wheel. 9/73 was when. The steering box changed and steering shaft attached to the steering column with the rag joint.

The breather is hitting a brace because it three and half inches further back with a four speed. I switched to a four speed thirty years ago. I added some fender washers to the front motor mounts which raised the front and lower anything behind the rear motor mounts.

 

[Steve Abbott]

Steering box and column rag joint alignment.

Good point. Fortunately for me, I don't have a steering column or shafts purchased or installed yet.

 

[Steve Abbott]

Unless it's been replaced the steering has a solid shaft all the way to the steering wheel. 9/73 was when. The steering box changed and steering shaft attached to the steering column with the rag joint.

The breather is hitting a brace because it three and half inches further back with a four speed. I switched to a four speed thirty years ago. I added some fender washers to the front motor mounts which raised the front and lower anything behind the rear motor mounts.

I'm at the hardware store now so I'll pick up some big washers. How far did you have to raise the front mounts? Also how big are the mount bolts?

 

[Living in the Past]

I'm at the hardware store now so I'll pick up some big washers. How far did you have to raise the front mounts?

That was Thirty years ago. It wasn't much, maybe two thick fender washers.

 

[Steve Abbott]

That was Thirty years ago. It wasn't much, maybe two thick fender washers.

Do you recall if you had to modify/change anything else after you shimmed the mounts? Thanks!

 

[Living in the Past]

Do you recall if you had to modify/change anything else after you shimmed the mounts? Thanks!

Mine still has the original engine. Were you originally motor mounts riveted to the frame? I shimmed mine for a little extra clearance at the back of the transmission cover opening. It a trail and error. On mine the brake drum on the back of the transfer case is very close. Everything clears and has rubbed anything.

 

[Steve Abbott]

Mine still has the original engine. Were you originally motor mounts riveted to the frame? I shimmed mine for a little extra clearance at the back of the transmission cover opening. It a trail and error. On mine the brake drum on the back of the transfer case is very close. Everything clears and has rubbed anything.

When I bought it, the frame brackets were missing due to the SBC/AT install by a PO. I sourced used frame brackets and installed them using bolts through the rivet holes in the frame. I have been wondering if those frame brackets varied over the years in terms of how far up/down the mounts sit. The rears seem right based on the fact that the DS rear mount basically sits on the frame.

 

[Steve Abbott]

Well, I tried to shim up the front engine mount insulators by about 1/4" but that caused the bolt holes to be out of alignment to the point where there was no way to bet a bolt started. I did determine that 1/4" Spacer was just enough to keep the TC HL shaft from hitting the bottom of the tub but only by about 3/32". Short of doing some cutting under the tub, I think using 1/2" thicker body bushings might be my only fairly easy solution...

 

[Green Bean]

Well, I tried to shim up the front engine mount insulators by about 1/4" but that caused the bolt holes to be out of alignment to the point where there was no way to bet a bolt started. I did determine that 1/4" Spacer was just enough to keep the TC HL shaft from hitting the bottom of the tub but only by about 3/32". Short of doing some cutting under the tub, I think using 1/2" thicker body bushings might be my only fairly easy solution...

This is the shims that worked on our 4-speed conversion.

 

[Steve Abbott]

This is the shims that worked on our 4-speed conversion.
View attachment 3724948

Did you put them under the pictured mount? My first attempt I put them on top between the mount and the bracket that bolts to the block.

 

[Green Bean]

Did you put them under the pictured mount? My first attempt I put them on top between the mount and the bracket that bolts to the block. View attachment 3725011

I can’t specifically remember but I think that the shims went on top of the mounts. (between the motor bracket and the mount)

 

[Skreddy]

My shims for my 4 speed conversion are on top of the rubber frame side mount and below engine side mount. I feel like I was right about 1/4”. Loosen the bottom of the rubber mount too and it should give you enough play to get them to line up.

 

[Living in the Past]

Well, I tried to shim up the front engine mount insulators by about 1/4" but that caused the bolt holes to be out of alignment to the point where there was no way to bet a bolt started. I did determine that 1/4" Spacer was just enough to keep the TC HL shaft from hitting the bottom of the tub but only by about 3/32". Short of doing some cutting under the tub, I think using 1/2" thicker body bushings might be my only fairly easy solution...

Bolt didn't line up with the thread not the bolt was too short? Did you loosen the back motor mounts? I did the front one first then the back which it just a bolt with loose nut. With front loose can use a larger punch to line up enough to get the bolt thru. The four speed is a tight fit with out cutting anything on tub or frame. I used a later four speed transmission cover which is taller and set up for the four boots for the shifters. The fan shroud hole might need to be enlarged to move the shroud up.