HELP!!!! I need some C4 transmission help

[GatorDoc]

Hey guys,
I recently rebuilt and reinstalled my transfer case. While I was at it I decided to tackle trying to fix some leaks on my 1975 C4. I replaced the pan with a deeper B&N cast aluminum pan, replaced the seal/filter. It still was leaking like a sieve. I looked closer and found it was leaking at the vacuum modulator. It is the press in style. I bought another ( green stripe), replaced it, and it still leaked. I removed it and put a little permagasket around it and...... it still leaked. So I removed it today and holy smokes did I find a mess. There are some massive cracks running through the insertion site for the vacuum modulator. Maybe from overtightening the bolts on the pan? I am thinking I probably did not do it with the replacement because it has been leaking pretty heavily for a while. Either way its leaking now to the point that I cant really even drive it. Is there any type of fix that does not involve removing the transmission? A sleeve possibly? JB Weld? Anything?
Thanks in advance for any and all help
G

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[pcf_mark]

Maybe the bolts were too long and bottomed out? Then as you tightened them it cracked it. Sorry you are in some real trouble now. Maybe ViperWolf can throw in some ideas.

Spray it down until is clean and squeeze some RTV in there?

 

[needabronco]

I'm assuming you could 'half ass' repair it, but you'll more than likely have to tear it down in order to determine the extent of the cracks. You might be able to TIG weld the area and either re-machine the hole or put some kind of sleeve in? Perhaps a new case would be a better/cheaper solution?

I personally would be very careful with RTV in an automatic transmission.

 

[Broncobowsher]

The crack goes through the bore. How much further does the crack go? How much further will it go?

I think the case is toast. A case replacement isn't that bad. Don't look for a Bronco C4, just a pan fill car C4. That will have the case you need. Lot easier to find and cheaper than a Bronco C4. Look at big 70's cars with a 302.

 

[Viperwolf1]

The crack goes through the bore. How much further does the crack go? How much further will it go?

I think the case is toast. A case replacement isn't that bad. Don't look for a Bronco C4, just a pan fill car C4. That will have the case you need. Lot easier to find and cheaper than a Bronco C4. Look at big 70's cars with a 302.

X2, it's done. Don't settle for a '60s pan-fill case because all your guts won't fit in it.

 

[GatorDoc]

I kind of figured it was toast. Thanks for all the help. I guess I will start looking for a new case.
G

 

[pcf_mark]

It can also be 2WD or 4WD case if you are hunting in the junk yard. I grabbed a bunch of external parts (linkage, kickdown, wiring, carb) from a rusted to death late 70s 2wd pickup.

Did you confirm the cause so they rest of us do not do that?

 

[GatorDoc]

I am almost positive it came from the bolts that came with the new B&M cast aluminum pan. The pan is the deep style therefore the bolts were longer. I should have measured them. It might have already been cracked as I was having a leak there before changing the pan. I probably made it worse with the new bolts. I rebuilt my transfer case and figured while I was at it I would fix the tranny leak....... Story of my life
Interestingly enought I only tightened the pan bolts 1 turn past hand tight. I didnt torque them down and they all sat even with no pan leak.
I am thinking I may try to clean it up and patch it with Cold Steel to get me through the summer. Then I would have a nice winter project. I dont think there is a lot of pressure at that area so maybe it will hold for a few months. Also I figure even if it doesnt work, the worst that would happen is I have a broken leaky transmission that needs replacing��.

 

[Viperwolf1]

You can try to plug the cracks but I don't think it will work. There is a throttle valve just inside of the modulator which controls the shift points. Not sure how high the pressure is there but it's got to be significant.