I’ve been away from my car and the Cougar community for about 10-12 years. As such, my car has sat neglected for too long. I finally got around to the car and after dealing with fuel system issues, got her started. And she sounded awesome.
Unfortunately, the joy ended there. I put the car in Drive and nothing. I then ran through the gears and still nothing. Added some fluid and was able to intermittently engage the gears and move the car back and forth. The transmission would more likely engage when I reved the engine, but that was a bit unsettling as I never knew when it would engage. I also noticed there was a faint high pitched noise when engaged. I tried checking the fluid level, but had a hard time seeing the level on the stick. I may have overfilled it a bit and will look at the level again and adjust accordingly. I’ll also look at the vacuum connections and make sure they are good.
Any thoughts or suggestions? Tests? Inspections? I’m not a transmission guy, but I’m willing to dive in and give most things a try.
You can get a pressure gauge and hook it up to the C6. Read the line pressures as you move through the gears. The FSM will have the specs for each position the shift indicator is in. If the car has been sitting for 10-12 years, the rubber seals in the clutch/ drums are probably hardened up. They will not hold the line pressure to engage. Your valve body could be gummed up from sitting that long. Between the factory service manual and a rebuild video from Bad Shoe Productions, you can rebuild a C6 pretty easily.
I’d probably replace any rubber vacuum hoses that run from the intake down to the transmission. Also related rubber plugs on the intake carb if any.
Fluid level is very very sensitive to oil temperature. So it needs to be up to temp for proper level check. That’s problematic if it’s hard to drive around. Bubbles that show on the dipstick can indicate overfill.
Check the vacuum modulator connections carefully. Your description sounds like it’s still low on fluid. The C6 holds a lot of fluid and one quart - the last one - barely moves the level on the dipstick.
I have had a few C6s that sat for 20+ years and one had trans fluid like syrup. You need to drop the pan and look inside. If its thick or gooey wipe it out the best possible and put in new fluid. Disconnect one coolant line at the radiator and with a pan underneath run the engine for about 10-15 seconds and then check that pan to see if the gunk is coming out. May need to repeat a few times. You need to clear out the pump, converter, and lines or you’re just mixing it with the new fluid and will have to drop the pan again.
Thanks for the replies. I really appreciate the input.
I think I found the pressure ranges in the FSM on page 07-5-02. For all drive positions at my altitude, the pressure should be between 49 and 56. Unfortunately, I don’t have a pressure gauge nor did I find where to hook it up.
I inspected the vacuum line from the carb/manifold to the vacuum modulator and all connections were tight and the rubber was pliable.
I then drained the transmission fluid and got about 2 quarts from the pan and another 6 from the torque converter (didn’t drain the converter completely as I ran out of drain pan ). Seems a bit low. I noticed a bit of sludge in the bottom of the pan and while cleaning it up noticed some “chunks”. I took pictures and have attached. The fluid was clear for the most part except in the bottom of the pan and completely clear coming out of the converter. It seemed like it flowed normal was not syrup like.
Seems to me that i may have been low on fluid as Royce mentioned. I’m still open to other ideas. My current plan is to pick up a new pan gasket in the morning and refill with fresh fluid. Thoughts or ideas?
I had the exact same thought. I looked up replacement filters and they look like my existing “filter”. Correct me if I’m wrong, but I don’t see how the screen mesh is going to filter the small stuff. Am I missing something? I did take my “filter” off and clean it up.
I just swapped out the fluid/filter/pan on my C6…the “filter” only seems to capture big chunks. I replaced the pan with a low profile aluminum one with a drain plug which makes it much easier to drain fluid, although a drain plug could be installed in stock pan.
The screen mesh filters can be cleaned. They are not meant to capture the old friction material which is what you see in the pan. You did good. The material in your pan is 1/10 as bad as I have seen with a perfectly good transmission.
These things (C6 + converter + cooler + lines) hold something like 12 quarts of fluid if dry. They are notorious for having a crack in the dipstick tube behind the O - ring which makes it appear you have a leaky pan gasket.
I just got back from a test drive and the transmission felt good. I’m still having a hard time reading the dipstick, but I think it’s about right. Shifted through the gears in drive and manually. The car was responsive. Had one time where there was a slight delay while starting from stop, but “hoping” it was a one time event. I’ll be driving close to home in the immediate future.
I’ll check out the FSM on band adjustment and do that in the near future.
). Seems a bit low. I noticed a bit of sludge in the bottom of the pan and while cleaning it up noticed some “chunks”. I took pictures and have attached. The fluid was clear for the most part except in the bottom of the pan and completely clear coming out of the converter. It seemed like it flowed normal was not syrup like.
