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74 f100 390 C6 Transmission started to shudder when hot. Drained 24oz. Added 24oz of Lucas transmission fix. After adding the lucas it drove great! Less rpm, hooked up perfectly. Was very happy. But when the trans warmed up more and more it started to slip more.
Shudder mostly gone. Yesterday I drove it again to see if the lucas still had effect. It's now slipping a lot. in all gears. Turning more rpm's. It's very noticable.
Noticed that on the bottom of my drain pan is a lot of black stuff. Cant see any metal shavings (perhaps caught on the magnet in the oil pan??). The fluid looks clean and bright red on a white paper towel.
I noticed that the level on the dipstick is pretty high, I've got a picture included. (Yes trans warm in Park and engine idling). No visiable foaming on the dipstick.
Question is: should I drain out some fluid and see if it stops slipping?
Should I also change my fluid and filter? I dont have any service history of this vehicle I've had it for 3 months and driven about 900 miles with it. Dipstick reading
Is Lucas compatible with a transmission that takes type F fluid? I could be wrong, but I think the type F fluid has more frictional material in it than the common fluid. Removing 24oz of your old fluid and replacing it with one that doesn't have that extra frictional material (plus the loss of the stuff from your transmission that was floating around) you've removed the ability for it to grab on.
Since you don't really know what's in it, perhaps you should drain everything, including the converter, change the filter, and refill with some type F and see what that does.
Since you don't really know what's in it, perhaps you should drain everything, including the converter, change the filter, and refill with some type F and see what that does.
That is a good option. Hopefully it will grab good. This could perhaps be a situation where the clutches are only operating on the left over clutch material thats floating around like caravaggio is saying..
Since you don't really know what's in it, perhaps you should drain everything, including the converter, change the filter, and refill with some type F and see what that does.
Update, yes it's been a while but I have finally got around to doing the above. Changed about 8,5 quarts of fluid, cleaned up the pan which was covered in fine metal shavings. Changed the filter. I also noticed that my vacuum modulator has dual lines, the secondary line wasn't plugged, plugged that up and man what a difference this made.
It hooks up great, shifts firmly into gear from neutral/park and the stall speed of the stock converter is just right. Should have done this earlier but oh well. The transmission doesn't shudder anymore when creeping at a stoplight for instance. Very happy, hopefully the trans holds up for a while, I know it will need rebuilding some day. I will add a shift kit to firm up the shifts, it's stock, so it's soft, I prefer a more firm shift. Thanks for the advice!
If by Lucas transmission fix you mean Automatic Transmission Fluid Conditioner https://lucasoil.com/products/proble...id-conditioner you may want to read the panel that has the bid red "Lucas Oil" at the top... there is an asterisk by where is says 'Compatible with most ATF fluids' and at the asterisk it specifically says it is NOT compatible with Type F. Would seem to suggest you replace all of your transmission fluid sooner than later. You might also note that while you drained the pan, from the amount you say you got out, you failed to drain the torque converter so you still had about 5 quarts of contaminated fluid remaining.
