Originally Posted by moaccountant
Thank you for all of your help. I still have to find the time to do the repair.
While I plan to do it, though, is there anything else I should do while I'm in there? That is, while I have the pan off? I have never touched a tranny, so this will certainly be a learning experience.
In addition to the code error, I do have a weird noise while idling in drive-- kind of a grinding/rattle noise. It also whines/rattles a bit when I back up. Any thoughts?
The whine in reverse is normal actually, it is due to a high pressure leak at the pressure regulator valve. The fix is to replace the pressure regulator valve with the sonnax replacement, this replacement will cure the whine noise and it also will give a smoother apply of the rear clutch when you shift the transmission into reverse.
When you have the pan off, check the 3-4 shift shift spring; this spring is located in the 3-4 shift servo. Also aside from the usual band adjustment I would seriously consider replacing the front servo cover with the sonnax replacement cover, this will correct the long slide 2-3 shift which all of these older 4spd torqueflites suffer from. Not only does this cure a long slide 2-3 shift but it also prevents burning out the rear clutch during the 3rd gear engagement.
The noise in idle with the gear selector in drive could be associated with the torque converter, the grinding can be because the torque converter clutch is broken or a piece of a vain has broken off and is circulating around inside the converter, this isn't very common however the torque converter clutch issue is very common. If you want I could suggest that you replace the spool valve, this won't fix the issue however it will prevent any future damage to the converter and it also makes for a firmer application of the lockup clutch. If you do want to replace the converter, you can get the pro king one from advanced auto it is part number CR63, I have used this converter before and it performs well. Not a racing converter but it is more than sufficient, consider it a stock replacement.
NOW, make sure that there isn't anything loose that is causing the rattling, check any heat shields, the hood, etc before you dive in and replace a converter. I could be wrong about the converter, but I could be right about it; so just be sure to rule out any possible causes.