TH400 "K" case question

[Corey Young]

Does a TH400 with a K cast into the bellhousing exist?

I have had TH350s and 700R4s with the K but all the 4x4 TH400s I have seen have large numbers, HD or both on the bellhousing. Post pictures of your TH400 bellhousing casting marks. Thanks!

[spidr]

The one that just came out of my 88 3+3 has an HD cast into it. I'll check it and see if it has a K, but didn't see one.

[Corey Young]

Here is a 4x4 case with a 39 casting, .25" bellhousing flange and a thin cast tailshaft housing .

[Corey Young]

Here is another one just like it, both had 205s behind them

[Corey Young]

Here is a 2wd TH400, no casting marks, thin casting for a platic or tin screwed on converter cover, .65" bellhousing flange, thin cast tailshaft housing.

[Corey Young]

Here is a rare one: x HD 44, .40" thick bellhousing flange and a solid tailshaft housing.

[Corey Young]

Here is a couple AMC pattern 4x4 TH400s, thin cast tailshaft housing. Watch for cracks where the pen is pointing, they will crack all the way around.

[Corey Young]

Campbell racing TH400 trans

[CtChevy]

so what your saying is if your building a th400 you want one with an HD cast in it

[Corey Young]

Here is a good comparison picture of the torque converter cover flange. The thicker one is for a cast cover with two reinforcement rods that go to the motormounts. The thinner one has a plastic or tin screwed on cover to keep dirt and rocks out of the converter. I had one HD case with the thick flange but it was not tapped for bolts, it had 4 screw holes which is an oddity. I drilled and tapped it for a cast cover.

[Corey Young]

Originally Posted by CtChevy

so what your saying is if your building a th400 you want one with an HD cast in it

Im just trying to see what the casting variations are. I have broken 3 TH400 cases and I know other people have too. I have read that some are stronger then others but have never seen pictures of where the strengths and weaknesses are.

[86DieselBurb]

Originally Posted by Corey Young

Does a TH400 with a K cast into the bellhousing exist?

I have had TH350s and 700R4s with the K but all the 4x4 TH400s I have seen have large numbers, HD or both on the bellhousing. Post pictures of your TH400 bellhousing casting marks. Thanks!

The TH400 in my 86 3/4, 6.2, Sub had the K case. Sorry can't post pics. But the K case must be fairly common because I bought a rebuilt TH400 from some guy on ebay and it also was a K case.

[spidr]

Originally Posted by Corey Young

Campbell racing TH400 trans

Mine looks exactly like this, it's too dark to get a decent pick, but same numbers and HD, same location. The flange section is approx. 3/8" thick, and it uses a cast aluminum cover for the torque converter.

[Jason4x4]

mine has 2 lines and 2 x's like this

-
-
x
x

[tacoma73]

I have a couple K case 400's, but they are buried in the garage. They do exist, I assure you.

[420willys]

I got this tranny in storage but can get some cast thickness for you if you need. But this is a TH475 from frito-lay truck.

Jason.

[Corey Young]

Originally Posted by tacoma73

I have a couple K case 400's, but they are buried in the garage. They do exist, I assure you.

Please dig one out. I just went to a friends house that said he had a K case but it was a HD bellhousing with the thick tailshaft casting.

[onetonwillysands10]

I have never seen a TH400 with a K on it . Until you have a picture of one I won't believe you. I have seen plenty that have HD or numbers on the housings that were in 4x4's. I own 5 CUCV TH400s and not a ONE has K. HD on two, and numbers on 3. Watched all but one be pulled from the vehicle to.

[Corey Young]

Originally Posted by tacoma73

I have a couple K case 400's, but they are buried in the garage. They do exist, I assure you.

Uncover these yet?

[tacoma73]

nope, they are behind 3 sets of tires w/rims and runflats, a 454, a Cummins drivetrain, and a freezer.

All of that stuff is heavy, and I'm not moving any of it to take a picture of a case that does exist in quantity.

[jeffers389]

so why does the 2wd version have a thicker bell housing flange? I ask because I am using it on my K5...... would a 2wd really be stronger????

[nvrenuf]

It's not a 2wd strength thing, at some point in the early to mid 80's they went to one type of casting so while they may have different markings on the bell they all have the 6 bolt flange (some drilled, some not - depending on application).

[RockTonka]

Same HD/28 case here with 3/8" flange, drilled(tapped) for cast converter cover...

[Corey Young]

Originally Posted by jeffers389

so why does the 2wd version have a thicker bell housing flange? I ask because I am using it on my K5...... would a 2wd really be stronger????

2wd TH400s don't have the heavy duty bolt on cover so they made the top a little thicker. RockTonkas has all the braces in place

[Corey Young]

So I broke another case and have been shopping for a replacement. The case that broke had a little crack when I bought it as a core but I didnt notice it. Here are 3 different Chevy TH400 cases

Left: standard 2wd
middle: standard 4wd
right: military or light commercial

not shown is a motorhome/commercial TH475 like the one 420willys posted. His has a rare aftermarket pan. Most have tin deep pans and drum e-brakes on the tailhousing.