Delta88conv455

Look what i found under the car today when i was changing left exhaust manifold!?

Looks like i have some welding to do...

It's a good thing that i noticed this at this point.. because if those last bolts had been broken all hell would have been loose.

What has caused this crack? Too much torq?
I bet those bolts have been too lose.

oldcutlass

Tough choice, I would get another case.

lshlsh2

I think I would replace the trans housing or the whole transmission rather than welding it. Either way as along as the trans is out you MAW,.....

Larry

Delta88conv455

Yeah, i thought about new case but my budget is very limited at this point.
It certainly would be the wisest thing to do.

Professur

I can't recall the details, but someone I used to talk with online had that happen to an automatic, and he got a replacement for just the bellhousing. Cut off the cracked cast from the trans body and the new one bolted up (I think) using the pump bolts to hold it on. I know it's common with manuals, but this was definitely for an automatic. Might be worth the time to look into it.

Found it.
http://www.summitracing.com/search/b...ion-type/th400

droldsmorland

Nice work. Something came unglued. Maybe a flex plate bolt or converter bolt? Or someone installed it wrong by not fully engaging the dowel pins and tightened her down anyway. Gota love the shade trees...Is the converter damaged too?
IMO DO NOT drive it! If in fact their is more damage than just the case which would be hard to believe there isnt, a flex plate will sheer through a floor tunnel and sheer your foot (feet) off.
Get a new case or a new trans. Welding old dirty aluminum is tricky it can cause brittle spots. Id be leery of driving it after welding. You want confidence dont you? As well as safety. TCI sells great street n strip trannys for around $1100. Put the numbers matching case on the shelf and call it a day.

svnt442

This is probably more than you want to spend, but it would probably be your best and safest bet for repairing that case.
http://www.summitracing.com/search/p...l-bellhousings

nsnarsk65cutlass

That doesn't look good it needs a case or like others suggested one of those bellhousing deals,it looks to badly damaged to weld back together.

MDchanic

Am I mistaken, or is that ALL of the attachment points on one side?

I agree that this looks like an installation error, rather than too much torque.

If you are a VERY good aluminum welder you could weld this, otherwise, it's new trans time.
Used long-tail TH400s are not hard to find or expensive.

- Eric

edit:
ps -
1. Change the flex plate as well - once the flex plate has done some flexing, it's had it.
2. post those pics on the "Wall of Shame" thread, 'cause someone really screwed up there!

Delta88conv455

Well... i'll get a transmission jack today and then i will get a better look at this disaster.
Looks like 4 out of 6 attachment points are loose...
I have a professional welder friend so he shall have to look at it.
Sure there has been a TRUE MECHANIC at work here..
Cracks looks like old ones, so there has been some GOOD LUCK.
I'll post some sad pictures as soon as i get the tranny out.

And thank you all very much for advice! My english ain't so good so sorry for any misspelling.

droldsmorland

I have a 63Kmile/101KM long tail TH400 from a well serviced 69 88, with paperwork to prove miles and service. But Im on the other side of the pond.

Delta88conv455

Ok...this is not what you see everyday
Pieces goes nicely in to their places.
There is one piece missing. I feel...angry and sad, but also reliefed...odd

Delta88conv455

MDchanic

I think it's broken.

What is the condition of the locating pins and their holes?

- Eric

Delta88conv455

Pins are fine and left hole is fine but right one is missing a little piece.
Flex plate and turbine is fine and tranny worked very well as i was driving.
I did not notice anything wrong while driving.

Professur

There's not a lot I wouldn't give to a good welder .... but I wouldn't give that. Yes, a good welder could save it, but nothing takes a beating like that well. You're going to have metal fatigue through out the piece. A welder that knows metallurgy would be the only one I'd ask to attempt it.

joe_padavano

I'd have no problem welding one tab on the bellhousing, but this is probably not worth it. My biggest concern is loosing registration of the passenger side dowel pin. If you loose concentricity of the trans with the crank, you'll have problems in the long run. I'd either get a different case or a Super Bell.

MDchanic

Not to be contradictory, but TH-400s are nearly indestructible in ordinary use, full size cars are in low demand and are being stripped and scrapped constantly, and the long-tail transmissions from these are in relatively low demand.

I'd recommend buying a used trans. from a junked car over your alternatives, for a non-souped-up daily driver like this.

- Eric

joe_padavano

That's likely the lowest cost/least effort solution, but I'm not sure those transmissions are as readily available as you might think. The last long-tail BOP TH400s were built in the latter half of the 1970s. They may not be as easily found as you might think. Any BOP TH400 case will work, of course, but you need to transfer all the internals to the new case. The nice thing about an Ultra Bell (sorry, I mistakenly said "Super Bell" above) is that you just cut off the old bell at the front pump and bolt this on. It has the added advantage that now you're NHRA legal.

Professur

I figured B bodies would be in fairly generous supply, having been the core of every police force forever ... only to discover that one local boneyard had brought in a shredder and virtually wiped out the 400 former cop cars they had. Old heavy cars for them are $$$ in metal. Less so in parts.

oldcutlass

After looking at the pictures, I would chance welding it. I would think alignment would be the only issue, would probably fab a mounting plate to insure that everything lines up.

Delta88conv455

Allright, the wisest thing would be a new tranny, i get that.

My professional welder friend looked at gearbox and he said that it can be done.
We are going to take a block and attach box to it so that tranny will line-up with engine.
He will weld bellhousing and reinforce it.
So lets just see how he does his miracles, and what is the result.
But i am going to be looking for a used non-welded case in the future.

MDchanic

Maybe I'm just getting old.

Has it gotten hard to find Model T coils and flathead Ford core motors, too, recently?

- Eric

joe_padavano

So long as it's only you...

oldcutlass

X2, I'm older, not old.

Lady72nRob71

Yowch! I have never seen that before... Certainly looks like an installation issue. Did you find the missing piece?

I think I agree.
However with a little JB weld and some duct tape, it will be as good as new in no time!

Delta88conv455

Nope. The missing piece is gone
But the hole is only about inch by inch wide so it can be done by welding.
And one thing is good that location holes are in place, though right one is little bit broken. I checked flexplate by measuring and its ok which is kinda weird because there was only one bolt holding... talk about luck

Seff

I have a BOP TH400 from a Buick if you need another case. A little closer than the offers from the US.

MDchanic

You da Man, Seff!

- Eric

Seff

Well, it's still heavy as hell to ship, but at least it wouldn't be going as far.

BA-68-5310 is the code, that makes it a '68 Buick GS 400 transmission. Should work JUST fine.

Delta88conv455

Thanks very much for the offer Seff, but it just turned out that a friend of mine has a TH400 at 20miles far from my house
The only thing is that it has a short tail. My tranny has a 9" tail. Well a few inch more to propeller shaft would do the trick

Seff

That sounds much easier.

This guy had some of the same problems: http://www.chevelles.com/forums/showthread.php?t=255244

Seems like you could change the needed parts over from your broken transmission and put them in your new one.

Delta88conv455

TH400hitsattuna (3) small.jpgAll welded up!
Was a easy thing to weld. Lets just see how this works..

lshlsh2

Glad you got it fixed. I would keep an eye on it for a long while and make sure it is holding up.

Larry

Delta88conv455

Yes, i thought about painting it mattwhite so i can see easy if it starts to crack again.
The welder said that the material was very good to weld.

MDchanic

That looks like a good welding job. I expect it will hold.

- Eric

oldcutlass

Hopefully it will hold.

don71

Amazing! I'm not sure I know of anyone that would tackle that welding job around these parts.

Professur

And now we wait. Best of luck ... looks like he poured plenty of heat and metal into the job ... fingers crossed that he got the metallurgy right.

svnt442

It looks like there is a broken bolt on the lower hole on the right side of the case?