c6 clicks into park and reverse but not in park or reverse
 

Hello,

I have an issue with a c6 and cant find any similar issues online anywhere. Your group seems to have a good knowledge base so I thought I would try here.

I have a c6 transmission that after disconnecting the linkage will click through all the gears including park and reverse but the truck rolls freely in park and wont move in reverse. It drives in low 2 and drive and has neutral, but no park or reverse. I dropped the pan, no metal or debris or visible issues. I can watch the arm go through all the gears but when it is in park I can roll the truck and it does not drive in reverse.

Any ideas would be appreciated.

Sorry to have to tell you this, but you will need to drop the pan again.
What you will be looking for is the inner detent that is moved by the lever on the outside of the trans. That detent has the 5-6 notches in it that a spring loaded roller rides in to keep it in the manually selected position. There is a connection either with a rod or a link that positions the parking pawn in one of the notches on the output shaft. It is very easy to see if it is functioning. The parking pawl could be broken or the pin that it pivots on may have come out.
At this time the only reason I can think of as to why you are not getting reverse is the link from the detent lever to the manual valve is either off or went somewhere.
If time permits when you get the pan down again, let us here know what you see or find and maybe we can provide some addl direction.
Last but not least the inner detet lever may have come loose on the shaft that is moved by the outer lever. Check that the nut is tight.

I would add one thing to Hanky's VERY expert advice: while in the pan, take a look at the rear (low/reverse) band and make sure that the anchor ends are there and intact. If they aren't you'll never have reverse.
Also, does it have 3rd gear?

I didn't want to go too deep on this because if everything appears OK with the parking mechanisms you may need to remove the driveshaft and tailshaft housing to get at the complete parking pawl system. It's not difficult, but time consuming and I don't know what your time schedules are. Let's hope you don't have to get that involved.
I agree with Greasemark regarding the reverse problem because reverse and direct clutches are both used in this problem.

Thank you all for your help. You were correct it was a broken reverse band and parking pawl. 2 different problems at the same time. Now I get to pull the trans.

Every once in a while, the old man gets one right. But not to worry, it's a really easy trans to pull and fix. It's kinda like eating a spam sandwhich; nothing too hard about it.