Going back to H42 - 78/40 Yertle's no Turtle

[1phrogguy]

Hi All,

A while back I purchased a 12/78 40. It needs attention in several areas. Plan to start with rebuilding the existing 70's Chevy 305 and replace the 3spd TH250 transmission with an H42 next month. It has the OEM transfer case afaik. Research has led me to believe that for a street/fire road driven 40, the H42 is a good choice for a replacement transmission.

It had ATF in the transfer case and it was leaking like a stuck pig when I bought it. I removed the transfer case because it was whining pretty bad and wanted to see what was up in there. The TC input bearing had some rust, still rolling ok but that needed to be replaced. When I inspected the transmission output shaft I knew it was toast, it had about half of the material left on the output shaft. New bearing installed in TC and buttoned back up with gear oil and it's running ok. One day it's going to go boom and leave me stranded.

I could have the existing transmission rebuilt, but I really prefer stick in these. Now's the time to get it done, including the engine. I'm having a local shop rebuild the engine and I've got an H42 w/ 60 series shift plate coming from @65swb45. Still need to get the correct bell housing, flywheel, clutch, mounts. Probably new TC input gear, drive shafts, and a bunch other things. I want to be sure all this stuff lines up. Any help is much appreciated. Hoping to have the drivetrain work complete by February '18 then dive into body work/power steering.

Here's some pics

Transmission output shaft ... How'd this happen?

Engine placement

 

[spotcruiser]

That wear on the transmission output shaft is really common. You'll find similar wear on the associated TC input gear.

 

[65swb45]

Ok, I can see the wear. As @spotcruiser indicated, you will probably need a new gear.

 

[65swb45]

John

it just occurred to me that one of the things we haven't talked about is propping this whole thing up. Is your current setup using the propeller mount on the back of the t-case?

 

[1phrogguy]

Here's what I've got going on now at the TC.

 

[65swb45]

Yup, you've got the propeller mount. Next time you're with the truck take a look at how the angle brackets are attached to the frame. You're going to need to move them if you want to reuse the propeller mount.

Another option is to build a 16 spline trans in an FJ60 housing that utilizes a mount UNDER the cast iron housing instead of screwing into the aluminum t-case. I don't have one ready to go, but I could build you one. I've done a number of these over the years. @Stumpalama comes to mind as one of many.

You'd have to fab a different crossmember to use it. But it is a vastly superior mounting platform. Especially for a V-8.

 

[1phrogguy]

I'll take a look at Stumpalama's threads. Right now let's plan on moving the mounts.

 

[1phrogguy]

Here's the current positioning of the shifters and my TC linkage. I assume that the TC shifter position will have to move forward.

It goes into and out of 4 hi and low, but it doesn't feel smooth.

Anything else I am missing? No idea if this linkage will work with the new set up or if it's been modded to work with the automatic.

 

[reddingcruiser]

Yup, you've got the propeller mount. Next time you're with the truck take a look at how the angle brackets are attached to the frame. You're going to need to move them if you want to reuse the propeller mount.

Another option is to build a 16 spline trans in an FJ60 housing that utilizes a mount UNDER the cast iron housing instead of screwing into the aluminum t-case. I don't have one ready to go, but I could build you one. I've done a number of these over the years. @Stumpalama comes to mind as one of many.

You'd have to fab a different crossmember to use it. But it is a vastly superior mounting platform. Especially for a V-8.

Totally agree. I couldn't wait to get rid of the propeller mount when I did my LS swap, wish I had done it years ago.

 

[1phrogguy]

@reddingcruiser why couldn't you wait to get rid of the prop mount?

No doubt that one can make a stronger setup mixing parts around and fabbing stuff made to fit. I certainly don't want anything to fail but it seems like overkill for a street/fire road cruiser to have that setup.

Ya'll are making it sound like a prop mount is a bad thing? @65swb45 How especially for a V-8? This adapter is made for V-8 conversions afaik.

 

[reddingcruiser]

@reddingcruiser why couldn't you wait to get rid of the prop mount?

No doubt that one can make a stronger setup mixing parts around and fabbing stuff made to fit. I certainly don't want anything to fail but it seems like overkill for a street/fire road cruiser to have that setup.

Ya'll are making it sound like a prop mount is a bad thing? @65swb45 How especially for a V-8? This adapter is made for V-8 conversions afaik.

Serving the t-case is a PITA.

And, IMHO, the propeller mount, especially on a A/T conversation, stiffens the frame too much because of the 4 point mount over such a long span. There is no flex in the engine/transmission combo. Mr. Toyota keep the mounting points closer to the front of the frame.

 

[65swb45]

@reddingcruiser why couldn't you wait to get rid of the prop mount?

No doubt that one can make a stronger setup mixing parts around and fabbing stuff made to fit. I certainly don't want anything to fail but it seems like overkill for a street/fire road cruiser to have that setup.

Ya'll are making it sound like a prop mount is a bad thing? @65swb45 How especially for a V-8? This adapter is made for V-8 conversions afaik.

In a nutshell, the torque often ends up pulling the studs/bolts out of the aluminum t-case housing, stripping out the threads in the process.

 

[1phrogguy]

AA bellhousing #712532 has arrived. Should have the rest of the kit Mark is making up for me shortly.

Never having seen an AA adapter like this in person, I took some pics to share. There are three machined holes that don't go all the way through the housing, remainder are finish type pictures, not sure even what to look for.

Two holes are like this, one on each side. The middle hole is not completely drilled though the back side.

This one is on the right side, that's showing the inside of the housing.

Finish pics

All probably normal for a Chevy 305 adapter afaik. Thoughts?

 

[65swb45]

Thanks for the pics John. If you could take a couple from further away, to get perspective, that would help.

 

[middlecalf]

That’s a new adapter?

 

[reddingcruiser]

Looks like the Quality Control department was out of the office the day this one went to shipping.

 

[1phrogguy]

@65swb45 Pics as requested.

@middlecalf It's supposed to be a new unit. Is there a sign I'm not seeing?

@reddingcruiser I was thinking the same.

The cast is pretty porous as you can see, just not sure if there's an issue or not?

Thanks all.

 

[65swb45]

Ok. If I understand correctly what you're questioning, it's on the two verticals at the front of the bell housing (the large opening) that faces the motor. It would be the two larger holes, between the mounting holes.

Those larger holes that are not drilled all the way through the housing are for the locator pins on the back of the engine. The holes only need to be deep enough to seat the pins. Form follows function.

Aesthetics? Well that's obviously another story.

 

[1phrogguy]

Those are the holes, thanks for clarifying. Is the third one on the side is for the clutch slave or something and meant to be the same way?

I don't need a shiny bellhousing, just want to make sure this is normal and will perform as advertised. Should I be concerned?

TIA all!

 

[middlecalf]

If Marks ok with it, then I’m ok with it. For me and my use of my rig functionality trumps aesthetics. Road crude does wonders for aesthetics.