C6 Sat for years, ready for duty?

[sideoilercat]

My car sat unstarted since 1982, someone stated that the clutch material can deteriorate from sitting. Any thoughts? I went through the motor, started it and all the gears engage. It's an early box around 66, if I remember we used stock ford clutches in it, has a B&M manual reverse pattern valve body and deep finned pan and also a B&M 8" torque converter. The fluid in it is the B&M Trick shift? blue colored stuff which I plan on changing. It had very few 1/4 miles on it before I spun a bearing and parked it in 82.
I don't want to tear it down if it's not necessary.
Thanks for any comments or suggestions.
John.

[Falcon67]

I'd be more concerned about seals in the unit getting hard over that time.  FWIW - and this has worked for me even though I called "BS" on it when it was recommended:  add a can of Trans-X to the unit, run it through the gears a few times, drain and add Type F.  If it gives trouble (usually delay in change from R to 1st or D) add another can of Trans-X.  We had a C4 in a street/strip car that had the "when cold" issue of backing up then not engaging the forward clutch until the unit got some heat in it.  My good trans guy said "try this as a temp fix" and damned if it didn't fix the issue after a couple of drives.  Usually, the only snake oil fluid fix I recommend is a cold beer after getting trailered at the finish line stripe by 1/2 of a 3rd decimal place.   

[gt350hr]

    Clutch material will NOT deteriorate over time. That is BS. As Chris mentioned there is a "slight" possibility that the seals fir the clutches "could" harden but this is usually only in high mileage dtreet transmissions. If it does have an engagement issue follw Chris 's suggestion of using TransX and MAKE SURE you drain it out as he's mentioned. It does NOT need to stay in there.
    Randy

[e philpott]

I would pull the pan for a look see , if visually looks fine and no rust install new filter , fluid and pan gasket run it through the gears with the wheels off the ground and see what happens  . If it shifts well and has all gears including reverse then check it for leaks

[fryedaddy]

i have a 66 model c6 in my comet rebuilt in 1987,drove it till 2005 then it sat till 2015.i changed the seals front and back,checked the filter and filled her up with fluid and i have been beating on it for the last 4 years,no issues.in fact i have been extra hard on it because i said im changing back to a 4 speed if the c6 will ever tear up.i dont want to change it till then,but the way its looking,its going to last forever

[cjshaker]

There is a chance that the front and rear seals will leak after sitting for so long. The front seal will often get a "set" after sitting for so long, and then leak when used. No way to know until you try it though.

I'd probably pull the pan also, just to look for rust. Condensation will do that, and I've seen it happen more than once. If it plugs up the filter, it can do more damage. Cheap insurance for the price of a gasket. Other than that, I'd say Chris is spot on. One of my first jobs as a mechanic out of school was rebuilding transmissions.

[Rory428]

Just my experience, in 1980, I bought a 70 R code Mach 1, that was originally a 4 speed, but a few years before I bought the car, the Toploader had been replaced with a correct 428CJ C6 transmission. The guy I bought the car from, had the C6 rebuilt in 1977, and when I bought the car, the trans worked perfectly, ATF was bright red, shifted great, it worked great. I drove the car maybe 2000 miles before I decided to a partial restoration (engine rebuild, bodywork and paint, and switch it back to a 4 speed.) My buddy was starting to build his "Pro Street" 67 Fairlane, with a 6.71 blown 427, and wanted my C6, so when he bought  it, he removed the transmission oil pan, and it was virtually spotless inside, and the ATF looked like new. Fast forward several years, and he finally gets his Fairlane driveable, and within 50 miles, the trans starts slipping badly, and the ATF is getting dark. Pulls the pan off the C6, and it had about 1/2 inch of clutch material laying in the bottom of the pan, and when the trans was torn down, most of the clutch plates had no friction material left on them, just bare steel. Now, maybe clutch material has changed over the years, but it would certainly appear that in this case, that sitting for several years did cause a problem, as the pan was clean before he stored  the transmission in his basement while building the car.

[sideoilercat]

Thanks guys I feel a lot better about the tranny. I did replace the front converter and tail shaft seal when the motor was out. I'm gonna change the filter and what fluid comes out (no drain on the converter) with type F, I think it's the same as the B&M blue fluid.
John.

While I was typing this I got the post from Rory428 and not feeling quite so good now, I would hate to send metal through an expensive converter let alone the rest of the trans. I guess if it slips I can shut it down before metal migrates, maybe. I might run it a bit then drop pan and check for clutch material.
Thanks again.

Then again it's pretty tough to tell if it's slipping with an 8" torque converter!

[Falcon67]

Hey - 8' converters need periodic service, so don't sweat talking it to your converter/trans shop and having it cut open.  I bumped my 9" converter to the max this year.  Pull the pan, clean it out, put in Type F and run it a bit, then do it over again.  Better if you have a deep pan with a magnetic drain plug.  Expect to fine at least a little metal - normal wear and tear.  If really worried, plumb in a filter between the pump output and the cooler. 

[67xr7cat]

Unless the transmission was submerged in water only reason for clutch plates failing is if they slip and that is what did in the clutches in the example above. If you don't have enough line pressure or the seals are leaking they will slip.

If it was mine I'd pull the valve body and make sure all the valves move freely. I'd also visually inspect that there is no rust in the pan, etc. Transmission fluid tends to suck up water so if it was stored in a damp area could have some corrosion.

As for clutch material the original ford clutches needed the type f fluid to help with the static holding capacity. Clutch material has improved a lot and on stuff since at least the nineties can run better fluid. That trick shift fluid is just dyed type f is all marketing hype. A good full synthetic be light years better today.

[e philpott]

I would imagine that the 671 Blower 427 contributed to the clutch failure

[67xr7cat]

Clutch friction material failure always is a result of too much slippage which causes them to heat up them the friction material fails. Only exception is if they are submerged in water.

Now is possible the unit was not built to handle the power of a blown 427 meaning there was not enough holding pressure (line pressure) and enough surface area (number of clutch plates) to keep from slipping, but the failure was not because the clutches sat around for years unless of course it was in a lake. 

[Rory428]

Actually, the blown 427 was quite a turd, the single time we took it to the track I only ran a mid 12 with it, so I doubt that the power hurt the C6, I ran mid 10s in my Fairmont with a non CJ C6 for years with no issues, this trans was a CJ version, and I really find it hard to imagine that 50 miles of mostly cruising around, on treaded tires would have cooked a trans that had been working perfectly in my 428 Mach 1. The clutch steels were not burnt up at all, it looks as if the material has just basically fallen off the steel plates in shreds. He had the trans rebuilt, and never had any more trouble with it, although to be honest, I doubt he put more than 500 miles on the car before he sold it.

[RustyCrankshaft]

C6 in my 73 Camper Special is the original 75k miles transmission that sat for 12 years (that I know of) until I pulled it out of a coworkers yard. Front and rear seal seep a little, but trans works fine, even towed a car on a trailer with it right after I got it running. In a month or 2 the 360 is coming out and a 390 is going in with nothing other than finally changing the 40 year old type F and filter. Ok, I MIGHT spend 3 bucks on a front seal when I swap the 390 in...maybe.

Have a 73 F350 dump truck factory 460/C6. Trans was swapped at some point with one from a Lincoln. Had been sitting for 4 or 5 years before I bought it. Didn't do anything but a fluid and filter change and it's been running ever since. Pretty much every time I patch a spot in the driveway I come out of the pit with 10-10.5k of gravel in the bed and it's still shifting fine 5 years later.

Have several more examples, but if the trans was in good shape when it got parked and didn't go through a flood then chances are it'll be ok. There are always exceptions, stuff happens, but I wouldn't be too worried.