I asked this at CK5 too but didn't get many tips there:

Engine starts as fine as ever, but is shaking terribly. No strange noise from the motor. No cracks on flexplate, removed the cover and inspected it (while engine running). If in P, the shaking is most. With rear wheels on jackstands and in N, driveshaft and wheels are turning but I could stop them easily by hand (no throttle). In D, 1, or 2 with no throttle they do turn stronger but still are stopable by hand and the shaking is not that much. I don't know if this is normal slippage of the converter. When in D and brakes are applied, there's a whining sound at the converter/transmission area. When NP208 in N and engine running I cannot engage 4H or 4L (tranny in P,N or D, with or without braking); every try ends in a very bad noise as like hitting something that isn't synchronized; have to shut down engine in order to shift.
So how is the best way to determine where the problem is?

CUCV K30, 6.2L TH400 NP208

Walter

Sounds like no slippage in the torque converter. These things don't have a lockup torque converter do they?
Does it move when the wheels are on the ground? You may have blown the spider gears. My Suburban acted similar when I blew up the Gov Lock. No shaking, but all other symptoms. When it was on the ground you could put it in gear, the driveshaft turned but the vehicle did not move=blown up rear end.

no lock up tc in th400, correct!
I put it in 4wd with wheels on ground and truck doesn't move, so it shouldn't be axle related.

Walter

sound like a bad tranny.

if the t/c is tight on the flexplat and the flexplate checks out i would say that you t/c shit its guts or the trunny pump did.

what is shaking? the motor? th etrans? t/c something should be visably moveing.

Whole truck is shaking :( but i think it comes from the converter-tranny area. Don't know what to do first:
- separate Np208 from TH400 or
- separate converter from flexplate
and run engine again

Thx so far.

Walter

its only 3/6 bolts and no spillage to do the t/c.

Sounds like its flexplate, or pump.

If its doing it in park.

its only 3/6 bolts and no spillage to do the t/c.

Unbolted the t/c now - 6 bolts on that old diesel ;)
Engine runs normal. Turning the t/c by hand sounds very bad, like you're shaking a can of metal balls. Definitively inside the t/c. I do have a spare, but am afraid that some chunk from t/c already found its way into the oil circuit of the th400.
Oh my, unbolting the transmission housing from the engine is such a pain! :mad3:

Anyway, thx again for all your advices.

Walter

Pulled the torque converter today. Something internal must be broken; when i shake it, there is a loud metallic sound like lots of needle bearings inside.
Don't know anything about torque converter internals. The oil from the converter seems not being contaminated or burned. Is it save to install the spare t/c and give it a try or could have some of the converter parts already found their way into the transmission?

Walter

Take this with a grain of salt, but if some metal chunks already found their way into the tranny, it's too late for it anyway, right? What would be the harm in putting on the spare converter and trying it out?

Flush and clean the old torque converter and drain the trains and put new fluid and filter in it. If the trans fluid looks good and there is not a lot of junk in the bottom of the trans pan...you're probably OK. Let us know how it turns out.

Put the new (used) converter in today. Drives like it should be. Thx for all your help here.

What caused the t/c failure. Maybe the broken converter wasn't built for the 6.2l/Th400? I changed it about 30.000mls ago, when i thought it is part of my driveline vibrations (was a bent rear shaft). Or my old detroit diesel has THAT much power, never noticed it though lol

Walter

I'd say the fins broke loose and were rattling around inside. Could be something else. I suppose you could empty it out over a 5 gallon bucket and see what falls out, might be interesting! You can find schematic pictures online of a torque converter, it is easier to view it than explain it. Then you may get an idea of what broke in it. Glad you got it fixed. Your 6.2 liter diesel engine is not a Detroit by the way. It is manufactured by GM. Lots of good info at thedieselplace.com.

I looked at some diagrams and how far i understand there are 2 turbine wheels (correct term?). One connected to the outside of the t/c and the other connects to the tranny via the output shaft. While spinning, oil is forced from wheel #1 to #2 and thats it (?).
Only oil (clean, more or less) comes out of the converter. It's broken anyway, maybe i open it.

6.2s were designed by Detroit Diesel Division of GM, at the time. ;)

Walter

Designed as a diesel engine from the ground up by the Detroit Diesel Division of General Motors, the original 6.2L diesel engine was introduced in the 1982 model year GMC and Chevy C/K pickup truck and full-size SUV lines.

Designed yes, but it is not commonly referred to as a Detroit Diesel. People think of a much different engine when you speak of a Detroit Diesel.

I would say the stator and/or the one way came apart.It settles in one spot and stays there when you start it :D

So cut it open and see :p

Designed yes, but it is not commonly referred to as a Detroit Diesel. People think of a much different engine when you speak of a Detroit Diesel.

but the 8.2/8.3 detroit is nothing more than a bigger 6.2 motor. 4 stoke, factory underpowerd, pretty much universaly hated.

When I think of a Detroit, I think of an engine like yours or a 60 series inline six.

I would say the stator and/or the one way came apart.It settles in one spot and stays there when you start it :D

So cut it open and see :p

Yepp, that will be done next . . .