About a year ago I asked a mechanic about changing the fluid in my C6 automatic transmisson. I was told not to change the fluid in the torque converter due to the age of the transmission. But I could have the filter changed and the fluid from the filter change replaced. Do you all think he knows what he is talking about? The color is pink on the dipstick, orange on the rag. I have no idea if this was ever done on this truck. The transmission works good, and I want to keep it that way. I've had the truck for two years.
Thanks in advance for responding!

 

I thing that mechanic was smoking something when he told you that one.

All automotive fluids need to be changed at recommended intervals because they breakdown with heat, pick up dirt and sludge with wear, and pick up mosture. Some torque convertors have a drain plug and some don't, so draining the torque convertor may not be able to be done easily.

 

If you don't drain the converter you are wasting time and fluid. Dropping the pan and changing the filter only replaces about half the fluid and once the engine starts the old and new fluid just mixes. best to go ahead and drain the converter. It's easy to do because all Ford trans up to 2000 has a drain plug in the converter.

As a side note if you don't change all the fluid in a Ford Aode at regular 30000 mile intervals then you are going to have the dreaded lock up converter shudder as per the Ford TSB. Just went through that with my 97 Mustang GT.

I have heard some old trans guys say don't change the fluid at all if the truck has over 75000 miles and never been changed and isn't burnt. Reason they give is if you put new clean fluid in you run the risk of the cleaner in the fluid breaking loose particles that may get in the valve body and stick a valve. Never seen that but I have seen total fluid changes in a trans with lots of miles cause the trans not to go into gear and/or shift right. Not from stuck valves but because the new fluid is thinner than the old fluid and would get pass the old hard clutch seals and not apply the piston properly. If that happens, then the trans needs rebuilding anyway.

 

I think that for the time being, I'm going to leave it alone. The trannie fluid's color is OK and the level is good. Yes, I too, feel that the mechanic was smoking some of that funny stuff. I stopped using his services due to some other off the wall theories of his. Being that the truck is not a daily driver anymore, This is not an urgent issue. Thanks for the replys, everybody!

 

If you drop the pan change the filter more then half of the fluid is being changed, especially if you let it sit for a while with the pan off. All thats left in the system is the 3 or 4 quarts in the tq converter and the quart or less in the cooling system. When you add the new fluid it will mix with the old and increase the friction modifiers in the old fluid.

He was giving better advise then you know. If you were to drain the tq converter theres always the chance it will not fill back up before you put it into a gear and it can be damaged. Of course this isnt likely but is possible, always better to be on the safe side. Of copurse ford put drain plugs on these for a reason now if they just stoped using studs we'd all be better off.

 

I aquired a 1983 F-150 with a 351W and C6 tranny. It has 160,000+ on it, and had never had a fluid change. The fluid was red, but smelled funny. I changed the fluid, strainer, and the torque converter fluid. Friends here told me that it was certain death changing the fluid in such an old tranny, but I went ahead and did it. The transmission shifts perfectly. Actually, it shifts more smoothly than it did before the change. No hesitation when putting it in gear or anything. I'm glad I did it.

I was really glad that I changed the fluid. I got to see the inside of the pan. Thankfully, it had nothing in it besides fluid.

 

The problem with changing transmission fluid that has been in forever is one of viscosity.

The new oil will be thinner and it will move around easier, that means it could seep out of gaskets and seals. I have seen three in the past that after a fluid and filter change the front seal blows out almost immediatly. It doesn't happen every time but don't be surprised if it does happen or if the transmission starts leaking in other areas.

 

Add a quart or 2 of Lucas Transmission addative with the oil change. I've flushed out black tranny oil on my 93 E4OD tranny at 200,000 miles and every 40k since. Have 270K on it now and will be changing it again soon, but i will be doing it myself this time since i was unhappy with how clean they got the oil last time. However, it still shifts excellent, and I have no slip.

 

I am not one to argue because all logic would say your correct.
But I just changed mine and thats why I am here searching old posts
because I changed mine and now the darn thing don't work at all.

 

i personally do know that if you can empty your converter when changing filter and fluid , all the better for your transmission, and to put it in a better perspective , following his advise would be like taking only half a bath, i know, i've built enough of them, later skm.