Hello all,
I'm hoping someone can chime in with some advice. I've been working on fixing my truck up - sandblasted/painted frame, 'new' cab, etc. When parked, the trans worked just fine (351W 4bbl with a C6 trans 4wd), but now all gears go in reverse. It's sure an odd one. Even when the trans is in park it seems like it wants to fight to drive in reverse, but the parking prawls are holding it from doing so. Other than that, R, N, D, 2 and 1 all = reverse.

Now that the truck is almost 100% back together, I'm guessing I'll have to pull the trans for a rebuild huh?

Thanks for any input!
Chris

 

Before you yank the transmission check and make sure the linkage is intact.

 

Maybe some thing froze in the trans. I know what you are saying I have seen this happen before and I just changed the trans be cause I dont rebiuld trannys. I would say your trans is bad but I am no pro at trannys

 

Sounds similar to something I had years ago with a Mercury station wagon, also with a C6. That one everything (including park) was 2nd gear. Tranny shop found the clutches welded, said it was common on vehicles that had been rocked forward/backward like getting unstuck. This one hadn't been stuck, had been driving normally, tried to back out of a driveway and went forward. So rough guess it's a clutch problem, time for a rebuild or swap.

 

The virtually bomb-proof C6 roared back to life tonight. So for those perhaps curious or for future search/answer sake, here's the 'fix'.

Since the trans had worked the night or two before, I figured it was something in the valve body that went out, like a o-ring or something on the reverse circuit. So I proceeded with drilling a hole in the bottom of the oil pan (yeah I know it sounds ghetto, but I've had it with some engineer thinking "we don't need a drain plug" or "we can save .005 cents per car if we don't include a drain plug" on the transmission pans, so after cleaning the pan up I proceeded to tig weld in a drain plug ). Now with that CLEANLY out of the way (it pisses me off having to clean oil off the shop floor if you haven't noticed by now lol) it took about 2 seconds to find the problem - somehow the shift lever post inside the transmission came out of the manual valve slot, leaving the hydraulics forever in a reverse selected position. I can't for the life of me figure out how this came out as it took undoing the neutral/backup safety switch and linkage, swinging the shift selector all the way forward as far as it would go, pushing the manual valve in the valve body all the way forward, and still having to (quite) forcefully pull the shift selector to get it to fall back in place. I few swings from park to first and back showed no signs of it popping out again, so on went the pan and in went the oil. After changing every fluid on that truck, and the transmission twice I feel like I've kept a small refinery in business for the month.

Diagnosis: This one goes in the book as a "wtf?" It's nearing x-mas so it must be them elves...

So it's again a happy purring C6 trans (albeit with a slightly shortened life span after trying to go forward and reverse at the same time). I'll probably give it a full rebuild this coming summer when I fix up the body. For now I just want a dependable winter/plow truck. We'll just look on the bright side and say it has "freshly resurfaced clutch packs"

 

Worn or missing shift lever bushings. Worn or broken shift detent. See my post in your other thread on this topic,