Author Topic: Cracked th400 case, wont drive, only moves in neutral  (Read 1530 times)

Offline fugett87

  • Newbie
  • Posts: 4
  • Newbie
Cracked th400 case, wont drive, only moves in neutral
« on: September 22, 2015, 09:56:43 AM »
Well, ill start by saying I drove past this truck everyday as it was sitting in a guys driveway. I could tell it moved from time to time but it was always there when I drove by. I stopped by one day to talk to him about it and ended up buying it, changed the carb, put a few degrees in the timing, checked the fluids, did a once over to make sure nothing was going to fall off, packed up the cooler and headed to the desert to see what she could meet some buddies at the fire pit and had a good time. When I was trying to leave she would not even turn over. Lights worked, fuel pump kicked on, just no crank. Traced the problem to a burnt fuseable link. Temp fixed it, got her home and re did all the engine wire harness and installed blade fuses in the place of the fusables.  She did great by the way, loose sand, hard pack creek beds, lo loc creeping over anything.

Thought everything would be good until some hard parts broke, and boy was I right.. and wrong at the same time.

About an hour into my next trip out she started popping out of gear, I know the shifters (column shift) are problematic on these trucks sometimes, so I checked it out, It was a little loose like I think it should be. I delt with it and kept on trail riding, until the throttle cable broke, I zip tied it and headed home.

The next morning I was checking some stuff out and I noticed the trans case was cracked. Right above the alignment dowel and went up over the top. Started looking, trans is missing a bolt, trans crossmember was now loose, missing a bolt and nut,  left engine mount was hand tight, and the 4x linkage was held in with bailing wire or the like.

So I drove this truck home the night before, I wasnt that drunk but i dont remember getting towed home, thats for sure... I hop in and try to drive it in the garage, it dont go anywhere, just revs. Im not a trans guy by any means, but Im certain the pump is out, I think maybe the stall came off the shaft somehow and the pump fried, somehow..

Case is cracked, pump is out. I need a new trans. Im not upset about it, $1500 truck..  :D 

But while im here, What is a good route to take? I got a 5spd sitting already, need a clutch, z bar thing, pedal.. or should I just stick a th400 back in and bolt the np203 back up and call it good? np205's require what exactly? a different output shaft? 27 spline? This is the first chevy truck ive had the pleasure of throwing my money at. I have lots of questions. is ORD really that good? I had like a hour long talk with a jeep guy who swore by some of their stuff.


Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18126
    • http://www.73-87chevytrucks.com
Re: Cracked th400 case, wont drive, only moves in neutral
« Reply #1 on: September 22, 2015, 02:05:06 PM »
If you like shifting gears then it comes down to what you have and how to get it bolted to the 205.  There are companies out there that make adapters for anything but if you have a well built TH400 it will go right back in and you are driving again.  And it will take all the abuse and break everything around it before it dies again.  If it isn't too far of a crack (past the pump) you can save the case and add a bolt on bell housing...

Offline Dr_Snooz

  • Junior Member
  • ***
  • Posts: 532
Re: Cracked th400 case, wont drive, only moves in neutral
« Reply #2 on: September 22, 2015, 09:27:14 PM »
I have a hard enough time juggling a clutch and brake when taking off on a hill. I can't imagine 4-wheeling that way.
1986 GMC C-2500 Crew Cab, 7.4L, TH400 -- RIP Chester

1989 Chevy Suburban V-2500, 5.7L, TH400

1990 Chevy C-3500 Ext. Cab, 7.4L, 3L80

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13270
  • Family is not an important thing. It's everything.
Re: Cracked th400 case, wont drive, only moves in neutral
« Reply #3 on: September 22, 2015, 11:22:52 PM »
heres my take. you can get the case welded back up, might not be the strongest weld but it should hold. many run the trans with only 4 out of the 6 bolts just cause they are too lazy to do it right. so as long as you dont try and pull the trans to the motor by tightening the bolts you will be ok (sounds like something like that was done already). make sure your transfer case is actually in gear. if you made it home somehow and no one gave you a tow then i dont see why you wouldnt even have 1st gear.
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline roundhouse

  • Senior Member
  • ****
  • Posts: 1474
  • Newbie
Re: Cracked th400 case, wont drive, only moves in neutral
« Reply #4 on: September 23, 2015, 09:22:31 AM »
We swapped in a NV3500 5 speed and love it

We used a 208 although your 203 May bolt up to a 5 speed


Sent from my iPhone using Tapatalk