TH400 issues with no gears

[madd0nk3y]

I had a TH400 that was dripping really bad in my 86 C30. So I decided to replace the seals. I ended up replacing the front pump seal and the O-ring around the Oil Pump and gasket. It was running perfectly before hand and when I re-installed it it was sluggish. At that time I just moved it about 10 feet and parked it as it was getting late and all gears were grabbing. The next morning I checked for a leak and nothing so I tried to drive it around the block. Took off kind of hard but it went. It did not make it around the block so I parked it and walked home to get my tools. I came back checked the tranny fluid, clean and full enough (read a little low) added 1/2 qt. Tried all Fwd and reverse gears and nothing.

Called friend over to see if he would help me push truck back. When he showed up, it took off under its own power so I drove it home but could feel it slipping really bad. Dropped the pan and it had metal sludge around the magnet and the bottom of the pan and new filter.

Checked online and read that maybe I did not seat the torque converter correctly, but this is just a wild guess.

What I would like is to get my truck moving again, I bought the ATSG and checked the following "NO MOVEMENT ANY RANGE"
Fluid Level...OK
Oil Pressure...Did not check before removing
Manual Linkage...OK
Torque Converter...Not sure how to test out of vehicle.
Transmission Internal...Afraid of damage because of sludge.


What could have happened? What can I do?

I bought a used TH400 off CL but have yet to attempt to install it with a brand new TQ converter.
I doubt the used tranny is going to work but with the new tq conveter I figured it was worth a shot but was told it had sat for 6 years.

[csb#356]

There is two sets of splines to engage and then some keys where the torque converter seats in the pump. So you will feel the converter "fall" in 3 times when it is fully engaged. If you didn't have the converter all the way engaged I wouldn't think the bellhousing would mate all the way up to the engine, but I haven't installed one incorrectly yet so I don't know for sure. Your converter can be checked by putting some pliers in the stator splines and making sure the one way clutch lets the stator freewheel in one direction and locks in the other. There is also an endplay spec for the turbine but it requires a special gm tool to measure.

The first thing I would do is pull the pump and see what kind of shape its in. You can put new clutches in it fairly cheap.

[Wrecked1982]

to know if the torque is set correctly remove the torque dustcover shield and unbolt it from the flywheel. it should turn freely. but i also doubt that the bellhousing would have bolted correctly if the converter wasnt fully in its notch.

[beamn7]

First thought was not seating converter all the way but I'm wondering if the pump gasket was lined up properly, did the pump seat straight, and did you damage the Teflon seals on the stator support (back side of pump)? If you unbolt the converter from the flexplate, you should be able to pry the converter away from the flexplate easily and have approx 1/2" and be able to spin the converter easily. If all is well, I would pull back out and inspect pump installation. Be sure to lube the pump "O" ring and teflon seals with trans gel or Vaseline before you reinstall.
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