I need a Torque Converter Cover for a TH400

[TimK]

Last weekend I was driving from Portland Oregon to Phoenix Az. I did the trip in 2 very long days. I got within 140 miles of Phoenix when my torque converter parted ways with the flex plate. It made one hell of a mess of the transmission, torque converter, flex plate, starter and torque converter cover. I have been able to replace all of the broken pieces with exception of the torque converter housing cover. I have tried the dealership and the local junk yards and no one seems to have one for a 1985 GMC Suburban, 4x4, 3/4 ton , TH400 and 6.2L Diesel.

Does anyone have one they would be willing to sell me?

Thank you.

TimK
kuhlrover@aol.com

[Dan]

While I can't help you out with the needed part I am curious to know if you sensed anything prior to the tranny going. Sounds, vibrations??

[TimK]

Dan,

I did here something different. I did this trip over 2 -14 hour days of driving and I think that contributed to the problem. Although I have put 20,000 miles on the setup I had, I believe the affects of running the engine not stop for 14 hours was key in the torque converter bolts vibrating loose. I believe the long duration of heat soak the engine sustained and the constant vibration over that extended period of time has a different impact on the engine components then if I were to get the engine up to temperature and drive it on 14 seperate 1 hour trips.

I noticed about a 1/2 hour before the torque converter seperated what sounded like an exhaust leak at idle. It was a popping sound that came from the back of the engine in about the same location as the exhaust header pipe connection. I assumed that over the long drive that an exhaust gasket had failed or and exhaust bolt had worked loose. At this time there was no noise at higher idle or at hiway speeds. Write before complete failure I started to here a tapping sound from underneath the truck. As I was slowing down and headed for the off ramp the truck made the distinct scrapping and popping of metal as if I was dragging a muffler or the rear drive shaft. I can remember looking in the rear view mirror fully expecting to see the muffler pop out the back side of the truck. When I got to the top of the off ramp I had no power to the rear wheels although the engine was still running but now it sounded like an ice crusher at idle. I was very disappointed to see no exhaust pieces on the gound or a busted drive shaft. At that point it was obvoius to me that it was a major failure of the torque converter.

I picked up the truck yesterday from the transmission place and I inspected the busted pieces. What a mess. The starter had a chunk of metal missing from the front bushing support. The tranny case had major cracks and metal separeration at the mounting bolts. The torque converter mounting bolts were stripped out. The Flex plate mounting holes for the torque converter were elongated, the transmission oil pump had some chunks of metal missing from the front cover and there is still a big hole and some crack in the torque converter cover. I have used some duct tape to keep the dust out until I can find a replacement cover.

TimK

[britannic]

Originally posted by TimK:
Dan,

I did here something different. I did this trip over 2 -14 hour days of driving and I think that contributed to the problem. Although I have put 20,000 miles on the setup I had, I believe the affects of running the engine not stop for 14 hours was key in the torque converter bolts vibrating loose. I believe the long duration of heat soak the engine sustained and the constant vibration over that extended period of time has a different impact on the engine components then if I were to get the engine up to temperature and drive it on 14 seperate 1 hour trips.
TimK Very sorry to hear about your disaster.

The engine, torque convertor and transmission are designed for continuous operation if necessary, punctuated only by fuel stops, fluid top ups etc.

If the T/C bolts were torqued correctly, the flex plate was in good shape and the starter wasn't loose, then you might consider an out of balance T/C, bellhousing not installed/secured properly, worn transmission and/or engine mounts as contributors to the catastrophe you had.

[john8662]

If still looking for a dust cover for a 4x4 I seem to think that the dust cover off another 4x4 that had a 700R4 is the same for the TH 400. I think that to be true!

[TimK]

I think this is more than just a dust cover. This is a cast aluminum cover with some pretty good size bolts attached to it. I have seen other tranmission covers that are just stamped sheet metal and this is a lot beefier than that. When bolted up it appears the cover on the TH400 makes the tranmission bell housing to be a complete 360 degree houseing. I also don't think the cover from a 700R4 will fit a TH400. A 4l80E might though.

TimK

[john8662]

On my 4x4 burb the cover is a cast aluminum cover that has bolt holes on the bottom of it that have rods that bolt to the engine mounts for stability of the trans and case, or to keep from breaking the trans case. I am not sure, but I think the covers were the same. I have a cover from a military blazer that had a TH400 in it. I don't have the trans but I have the cover from it and it looks just like the one from the 700. I will look tonite and see if they are the same. The stamped sheetmetal version of the dust cover you are referring to is the one used on the 2wd trucks.

[john8662]

Update: As best I can tell, the cover I have for a turbo 400 with a 6.2 and 4x4 is the same as the cover for a 700r4 with a 6.2 and 4x4. I think the 700 & 400 cover are the same as long as its in a 4wd truck that has a 6.2DSL in it.

I have an extra one if interested..

[britannic]

I used the cover from my TH400 on the 700R4 and it fits fine, the only difference is that the "K" case 700R4 doesn't have the top 2 bolts as the bellhousing ears are removed - it doesn't affect the cover's function or fit.