TH350 always in drive

[Chevy]

My '51 chevy p/u with 350/350 combo, ifs, power steering and power brakes is getting close to road-worthy.

I started the motor and needed to move it around the yard a bit so put it in gear; first and reverse worked OK. But i had more pressing issues than the tranny, like engine cooling etc to get worked out, so was concentrating on those. I was just getting back to the tranny and the car started up but was in reverse, even though the selector was in P! I have a later model chevy truck steering column, with column shifter, and linkage to the TH350. You can feel all of the detents. I started the truck again and i only got forward gears. Truck starts up in "drive", stays in "drive" no matter what gear you put the selector in. I pulled the pan, there was a little sludge in there but the fluid was still nice and pink, not black or smelly. I confirmed that the linkage has no binding, and when the column shifter is in "P" the internal linkage is in "P" and the "s" link connecting the linkage to the piston is in place. I took three quarts out with the change so put a new filter and three quarts back in, Valvoline Dex plus Lucas Transmission Fix, which states "frees stuck valves" which i assumed was the problem. Since i can't place the vehicle in park, i can't get a reading of fluid level according to the owner's manual. With the car in "P" (but trying to drive away) and the brakes applied, the fluid level is just at the add line. I still only have drive no matter what gear the selector is in.

I searched lots of forums, found a few people post this problem but no solutions other than check the "s" link...so hopefully someone here can help.

Any suggetions?

Thanks!
Paul

[Jake's Performance]

There is a nut that holds the "rooster comb". Is it secure?
The S link is in place?
Did you watch the internal linkage while someone shifted the trans at the column?

Does it drive forward in neutral as if in low, stall in reverse and rev against the converter but not move? Does it stall against the converter in park?

Jake

[Chevy]

There is a nut that holds the "rooster comb". Is it secure?
The S link is in place?
Did you watch the internal linkage while someone shifted the trans at the column?

Does it drive forward in neutral as if in low, stall in reverse and rev against the converter but not move? Does it stall against the converter in park?

Jake

Jake--thanks for the response! I haven't been able to get the truck started the last few days so sorry for the delay in getting back to you. I had to run a new fuel line to get it started back up but was able to do that today. Here goes:

The nut holding rooster comb is secure. I did watch the internal linkage when someone shifted, and it seemed to work fine (went through each location in the rooster comb, and pulled the piston in and out via the S link. The S link is in place. Or at least was, when i put the pan back up.

As for your last question, it acts like it's in drive no matter where it is. So, it drives in P, R, N, D, 2, 1. As far as i can tell it behaves exactly the same at each of these locations. If you hold the brakes and give it gas it will spin the rear wheels no matter what location the column shift is in. If you let the brakes go it will sorta idle forward. Foot on brakes, it idles like it would in D at a stop light with foot on brakes.

Any ideas?

Thanks!
Paul

[Jake's Performance]

Sounds odd,
If all the linkage is working internally and externally, something is amiss.

I suspect we are missing something with the diagnosis.

The reason I asked the above questions, if the forward clutches are cooked, they weld together and the trans will always try to drive forward.
In reverse, you basically get a transbrake effect, it will stall against the converter but not drive.
In neutral it will act as 1st.
In park it will stall against the parking pawl and may overcome the pawl and go forward but it will be noisy.

All the drive gears will act normal.

I think you have a "loss of motion" somewhere in the linkage causing your problem.
I would suggest you go back over everything and check it out, not with the mindset that "I've already checked this" but with the mindset "my twin brother worked on this thing and now I have to figure it out". :D