Otis

Well, it looks like the valve body lock up spring is the culprit. As always, Goerend has been very helpful. Craig spent quite a bit of time helping me diagnose the problem and shipped out an updated (larger) spring. I'm also going to replace the lock up solenoid as long as I'm digging into the valve body. It seems like I had several unrelated issues all causing problems. I should have more updates in a couple days once the parts get here.

9812vram

Lockup spring? What's that? Where's that? I never heard of a lockup spring before. I thought there was just an on/off solenoid to control hydraulic pressure to the piston inside the converter....

Otis

I'm pretty sure that's what Craig @ Goerends called it. It's on the driver's side toward the front of the valve body. He sent me a new one today. Here's a pic he emailed me today to help with the troubleshooting. The spring is behind the round plug in the bottom portion of the valve body (just left of center). It is obscured from 3-6 o clock in this pic.


I'm new to this voodoo world of the auto trans internals, so my terminology may not be correct. I'm comfortable putting them in and taking them out, but this is the first time I've done anything beyond that.
-Jon

9812vram

I'm interested to see where this goes. Post some pics when you get it apart....

infidel

Yes, I'm interested in how that plug comes off.

Otis

First, I'd like to apologize for the poor picture quality and lack of Photoshop skills to point out landmarks. I'll do my best to detail the progress...

First, remove the forward 2 T-25 Torx head screws, and loosen the rear one. (all 3 are perpendicular to the truck frame). Remove the vertical T-25 in front of the plug. There is enough play to move the cast housing aside to get a magnet in the plug. The plug is in the shadow in the center of this pic:


Here's a brighter shot after the screws have been removed, housing shifted, and plug with broken spring removed.


The damage:


The spring was in 2 pieces coiled together but was so brittle it broke a couple more time as I was separating the pieces. That's all I can do until the replacements arrive. I think we're on the right track.

-Jon

patdaly

I think you mean the switch valve spring. This is the picture I got from Dave when we were diagnosing my no lockup condition. Sorry, guess I gotta post the thread it is in.

https://www.dieseltruckresource.com/...d.php?t=258311

9812vram

Sure looks like you're on the right track! Thanks for the pics.

Otis

Close, but its a different spring. In the attached pic from this post:
https://www.dieseltruckresource.com/...94&postcount=5

The spring I broke is behind the plug on the very right of the picture, just above the transmission filter.

Otis

Its up and running again. I got the new spring and plug installed, new TC lock up solenoid in, the TPS linkage bushings replaced, and the TV Kickdown cable adjusted. Smooth sailing. Here's a pic of the new vs. old spring and plug design.



I should have put something in the pic for scale. Those plugs are just over 1/4" in diameter. Thanks for the help.

-Jon

9812vram

Aaaawwww heck. That's not so bad! JB Weld that thing back together!
Thanks for the pics!

infidel

Maybe now that spring is short enough to use in your overflow valve.

Nice to have a somewhat complicated problem with a simple fix.

Otis

Its funny you mention the OF valve. I just put in a new Larry B's valve and shut down solenoid today.