The newbie and his TH400

[wikd69]

Ok, a buddy just dropped off a used TH400 at my shop. This trans is out of a 1 ton pickup and is the HD case. Assuming its usable I'm going to transplant everything from my current TCI trans into it. This is the second TCI competition trans this little blower motor has eaten. The first one lasted 4 days before I spun all the case lugs out of it. This one has a couple thousand street miles and about 18 track runs on it. After the last track visit I dropped the pan and found one case lug laying in it so it's only a matter of time before it checks out and leaves town too. Never again will I do business with TCI. Your mileage may vary.

So. I've never been into a TH400 before (or any other automatic for that matter), so I'm looking for some advice from the group. Can you point me in a good direction for shop manuals or other sources of information on rebuilding one of these puppies ? My current trans has some good hard core parts in it and I'm thinking I should be able to transfer everything from the old to the new, without running into a lot of issues. I do have a transbrake and a vasco solid input shaft but I don't think they really have anything to do with the case. As far as I know, a case is a case is a case...

I'd expect to replace the soft parts (seals, gaskets, o-rings, etc.) but unless I find bad clutches or whatnot, I should be able to transplant everything into this new case.

Any advice for a newbie ? I'm not gonna dive into this thing for a couple of months, but I do want to have all my ducks lined up.

So, besides finding a reputable trans-shop to do this instead, what advice would you all offer up ?

[DOTracer]

Better off finding someone who knows how to build the trans without stipping the lugs out. Also there's a case saver that slides on the band pin to support the spirolock.

I ran a th400 for several years running mid 9's at 3400 lbs and never once had an issue with the case lugs.

[vegaracer]

You can get a Haynes manual I think or try this: http://www.themotorbookstore.com/howtowowiand.html

[wikd69]

Better off finding someone who knows how to build the trans without stipping the lugs out. Also there's a case saver that slides on the band pin to support the spirolock.

I ran a th400 for several years running mid 9's at 3400 lbs and never once had an issue with the case lugs.

And I now have two of them in a row with this problem. Lucky me

Yeah, Coan sells a nice CNC piece that conforms to the case inside.

[ytnova]

They sell a full size HD snap ring so you don't do that to the case. I dont have a part number, but any good trans guy should know exactly what it is.

[molevolent]

one thing you will want to watch is the check ball location, depending what tci did for a shift kit they might have eliminated some from the valve body.
just incase your still doing it on your own.

[wikd69]

one thing you will want to watch is the check ball location, depending what tci did for a shift kit they might have eliminated some from the valve body.
just incase your still doing it on your own.

thanks

[Shoedoos]

http://www.v8buick.com/showthread.php?t ... on+rebuild

http://smartflix.com/store/video/3098/G ... ing-Series

http://www.nastyz28.com/ubb/Forum12/HTML/005249.html

[evil16v]

The one on the Buick board is pretty damn good. Pictures galore.

[wikd69]

The one on the Buick board is pretty damn good. Pictures galore.

Yep, and there's another great photo thread on MinnesotaMud too.

[Ls7camaro]

I came into some money when I got my Camaro, rebuilt the 327 and bought a new transmission, I got the whole kit from TCI(this was about 6 years ago) trans, conver, cooler. I bought everything they recommended. TH400, 10"converter and Super Trans Cooler. It lasted about 20 miles. The Sprag??? was out, a good tranny guy looked at it for me. I had to pay the shipping back, and they sent me a new trans. This time, right from the get go, did not work, again, pulled the trans and looked in the pan, and my buddy immediately started pointing out problems, just by looking(I don't know what he was looking at but he was pointing things out that he said where not right), so it went back to TCI, I got another Transmission but this time I had pulled the motor for a rebuild (summer was pretty well gone from dorking with this) and I got the new transmission, stupid me, I never opened the box, in the spring, I put everything back together, and guess what, it backed out of garage and spewed trans fluid everywhere, the case was cracked from by the pump, it moved, but poorly, so I called TCI, and they told me it was out of warranty, I should have checked it when I got it. SO, I con't care if TCI sales Oxygen to breath, I will not buy it from them. They have good salesman, and terrible customer service and a product that I will never use again, I took the trans cooler off and gave it to some import kid, NO TCI crap on my car.

[wikd69]

I got the whole kit from TCI

Yeah, my story is similar. I bought the hardcore 212506 TH400 from TCI, though I'm using a B&M converter.

Installed the first TH400 I receieved from them and it would not stop puking fluid out the top vent. I screwed with it for a week or two before I finally pulled it and shipped it back for replacement (from Calif to Miss).

The second transmission lasted all of 4 days, split the sprag, took out all the case lugs.

The third transmission (another warranty replacement) spit some case lugs into the pan after about 16 runs down the track. I probably don't have 3,000 miles on this trans, plus the track runs. Go figger.

All of this over just about a year and a half or so - I had the Camaro up on stands forever, waiting on TCI to return or replace my trans.

So, yeah, I feel your pain. I have this HD case sitting in the shop and I need to swap the internals from my (still) functional TH400, *before* I lose the rest of the case lugs and shred the trans. This time I'll do it here locally and install the case-saver piece from Coan. That should help a bunch in longevity.

I'm thinking I'll attack this over the next two or three months, pull the motor and trans, and do the case-swap while I have other things going on with the motor. We'll see.

[Ls7camaro]

Have you ever heard of REDNECK PERFORMANCE? My dad was looking at their stuff, TH350 w/Trans Bracke and 9.5" converter, for not quite 1400 bucks, I was interested to see if any one else used their stuff.

[wikd69]

Have you ever heard of REDNECK PERFORMANCE? My dad was looking at their stuff, TH350 w/Trans Bracke and 9.5" converter, for not quite 1400 bucks, I was interested to see if any one else used their stuff.

I have not heard of this outfit. I'd hit Google and see if anything at all popped up. Are they local to you, or at the end of a shipping delay ?

[krazyhorse1]

well wicked you are in for a surprise there is really nothing to building one. i do suggest you use the coan piece. there should only be five check balls when you pull it apart. oem there are six but you take the one out for third so you get more flow to hold it from slipping. i will find you you a diagram for the placement of the check balls. i would recomend you completely take apart your valve body to clean and check for galling of the slide valves and for excess wear. if it is wore out you could either replace or repair with bushings I.E. machine work. if you need anything new i would go with hughes stuff. for what it is worth i would go ahead and replace the clutches while your in there so you dont have to go back to soon. also take your pump apart and inspect it also mostly for trash and galling of the gears. oh yeah in case you want to know you are breaking case lugs because you have to much line pressure. you need to limit it to about 150 to 175. tci is notorious for to much line pressure. not that you want to but tci has a great rebuild book that is a copy of the gm original. tons of pics.