OT Auto Tranny Fluid Change

John T · Dec 6, 2011

Okay, lookin for good reasons why and why not. I inherited the "preventive maintenance" gene and usually do it and never had a problem thereafter. Some say if it aint broke dont fix it, but Ive often violated that rule lol

When I have a vehicle with an auto tranny and even thought it shifts PERFECT, somewhere around 100,000 miles I get this uncontrollable urge to have the tranny fluid power flushed (supposedly that changes the torque converter also??, mechanic buddy has huge expensive Snap On or other brand of power AT flusher) and refilled and change the filter also, and nowadays I refill with Synthetic Fluid. IVE NEVER HAD ONE GO BAD AFTER THAT. Ive also considerd hanging a magnet on but never have.

NOTE Im my RV or trucks I also add a big honkin external tranny fluid cooler, I think they help big time if youre pulling something.

ANY GOOD REASONS WHY I SHOULD STOP THE PRACTICE???? Ive heard some say never change it is why Im asking

John T Just a Preventive Maintenance Kinda Guy (Heck I may run out and change the air in my tires, that nasty stale air in there is gettin old lol lol)

rhouston · Dec 6, 2011

"(Heck I may run out and change the air in my tires, that nasty stale air in there is gettin old lol lol)"

You need to change that air to winter air if you have summer air in there.

There is/was a thread on that somewhere around here.

Anonymous-0 · Dec 6, 2011

I change mine and don't have any problems either. Heck I even change my manual gear boxes and transfer cases to 0W30 synthetic and notice smoother shifts and zero leaks after hundreds of thousands of miles. If you feel froggy, jump!

Ky. Hauler · Dec 6, 2011

Change it!! I do.

IaGary · Dec 6, 2011

I had a 2004 or so Ford Explorer. First time I got an oil change at my buddies shop I did some looking around under neath it.

There was no way to drain the tranny and no dip stick to check it if I remember right.

Buddy said if it doesn"t leak and still works you just leave it alone.

Gary

Ray · Dec 6, 2011

I was going to check the tranny fluid in my sons 08 pontiac and couldn't find the stick.The owners manual says you don't need to check it.

oldtanker · Dec 6, 2011

John this is what I was told by a tranny guy in his own shop. "I love those system flush guys, they keep me in work". He claims that most of the time what he is seeing is cars that have been flushed for the 1st time around 150K without a filter change. He thinks that the flush and fresh oil creates enough action that it is breaking up deposits and crud in the pan and the filter gets plugged. He also says that he has never had a customer that they had the flush done at a place that insist on changing the filter too.

The cooler is a big help as heat is the worst problem with slush box trannies. The lock up converter, synthic oil that withstands more heat and imporved coolers have seen auto tranny life about double sense the 60's. On 1/2 ton pickups they stopped putting car trannies (C4, TH350 and 904A) in them and are now using trannies designed for a lite truck.

Rick

davediehl@hotmail.com · Dec 6, 2011

I bought a new Thunderbird in 1995 and it was a left over 94 model. After the warranty period expired, I took it to my regular oil change shop about a block from my home. They claimed the tranny fluid was discolored and 'scorched'. I refused the change as I really didn't trust their judgement when the dealer said all was normal only a few months before. Well, that fluid is still in there and it just rolled 124,000 miles. Never a problem...

Anonymous-0 · Dec 6, 2011

Several years back I had a pickup with about 100,000 on it and was talking to a Ford mechanic one day and stated to him that i needed to change the transmission fluid. Had never changed it. He said not to as he would just a about guarantee me that the transmission would go out. Never changed it and was still good at 170,000 miles. Have never changed one since, but i don't do a lot of heavy pulling with them either.

evilboweivel · Dec 6, 2011

had the fluid changed in a 03 PT Cruiser at 110000
changed the trany less than 5000 later
mechanics who did the trany change said it was due to fluid change.
said to change it before 60000 or not to change at all
Ron

M-MAN · Dec 6, 2011

John T;
I prefer the old fashioned way. Pull the pan, drain it and change the filter. Like you I get that urge around 100,000 and change it. After that I go 50 to 60,000 between changes. The Taurus I'm driving now will get another change when it get's 25,000 miles on it because I don't think the previous owner changed it. I think it's more important to change it now a day's with all the electronic's in the tranny and torque converter.

BTW, there's already a magnet in the pan. lol

Anonymous-0 · Dec 6, 2011

Change it don't flush it. Use the proper oil and you will have satisfied your curiousity about the condition of your oil.

Nancy Howell · Dec 6, 2011

Asked abut that when I bought my truck. My mechanic (who rebuilds trannies) said if you don"t do it before 100k, don"t do it at all. The new fluid could cause deposits to break loose and cause problems.

I change the tranny fluid & filters on my 97 7.3 diesel F350 4sp auto every 25,000 miles. It had 97K when I bought it and went ahead and changed it. It has 161K on it now and no problems.

I am absolutely a preventive maintenance person since I do 99% of my driving by myself. Last thing I want is to be a couple of hundred miles from home with horse & trailer and have a break down.

farmer boy · Dec 6, 2011

I wouldn't touch it with a power flusher. Drop the pan, change the filter and put new fluid in the pan. Get the pan cleaned out and take a look at the magnet and clean it off. A cooler will help any vehicle. Can never be too cool. The TC lock will only lock up when it's warm enough anyways, and unlocked it builds heat fast.

Mike M · Dec 6, 2011

Now on the tranny oil ? who knows what to do. May be best to follow manufactures recommendations.

Now on that stale air you may want to change it to nitrogen. I have it in one of our cars and it sure does keep the pressures stable. I use my air/chuck gauge combo and likely get some air back into them so I hope a little doesn't bother it.

slim · Dec 6, 2011

Here's what I do. Do with it as you wish. I don't drop the pan at all. Don't want to get crud in it and don't want a leak. Instead, I take the return line from the cooler loose, start the engine and let it pump out. Stop the engine, fill with fresh fluid and repeat until I am only pumping out fresh fluid. Then I add an inline filter, reconnect the line, top off with fluid and I am ready to go. This way I have a fresh external filter and fresh fluid. However, my internal filter is still dirty but that's the tradeoff.

If you only drop the pan, you are only changing about a third of your fluid. I firmly believe in external filters and coolers and fresh fluid. I don't believe in flush machines at the lube shops. This way takes about 12 to 15 quarts of fluid. It would be better to also change the internal filter but I have not had any problems yet doing it my way.

slim

37chief · Dec 6, 2011

I have been told never to have a trans flushed. That is all I know about that. Now as for the fluid change I do it a bit different. I pull the pan, install a new filter. I add just the same amount of fluiid I removed. Then I remove the pressure cooling line to the radiator from the trans. I attach a hose to that line. No need to do anything with the return line from the trans.Then start the motor and remove a qt of fluid. This happens very quick. Add a new qt to the trans, and repete this until you see new fluid comming out of the line. This is a little messy and may use a bit more fluid, but you will get almost all the old fluid out. I could never understand why do just a half of a oil change. Stan

Dave Sherburne NY · Dec 6, 2011

Ask the car doctor he's done more than all these guys put together.
Texas car doctor

S2710 · Dec 6, 2011

I just got a 99 F250 with a 7.3 power stroke this fall with 240,000 on it and the tranny fluid and filter has been changed every 30,000 miles. The tranny shifts smooth and the TC locks up just like it should. I had a Tranny guy look at it and he said that if you change the oil and filter and don't abuse them they shoud never give you any problems. Now watch the next time I pull something the tranny will go out. LOL

Bob

donjr · Dec 6, 2011

Good friend of mine is in the automatic transmission rebuid business. About 15 years ago my Dynasty decided to lock up, about 50 moles from home. It had about 90,000 miles on it, and hadn't been touched with a wrench. Ralph said 50-75,000 miles is about the limit for tranny fluid (like motor oil) to be dependable. It just wears out. Been keeping things changed at about 60,000 miles since, and had no more problems. It costs about $100, but a new tranny is $1500 or better. Vet always costs $50 or $100, but is cheaper than losing a cow. Oil change costs $39 or $40, but beats an engine rebuild. Guess I can afford a buck to get another 50,000 miles.

dhermesc · Dec 6, 2011

You can't change it the old fashion way. Few transmissions have drain plugs on their torque converters.

I wouldn't use a power flush either - let the transmission pump do the work.

Some people claim you have to replace the screen (not really a filter) to change the fluid. If your transmission is working as it should the screen will be clean - the clutch packs wear with small enough particles to pass through the screen, it they are breaking off in big enough chunks to get caught in the screen the transmission is toast anyway.

Best thing is to read your owners manual and service at the intervals it says. Usually you need to follow the regular or extreme duty schedule for the warranty to be good.

Texasmark1 · Dec 7, 2011

My current '11 Silverado 1500 has absolutely no listing for differential nor auto trans oil/filter changes in the owner's manual. I do know that the fluid in both is either semi or full synthetic.

The 1500 Dodge trucks I have owned prior to this made mention at 100k to change both in the tranny, no mention of diff.

So, having lived through many 10's of iterations of having the mess of getting the pan off, making the filter change, and getting the pan sealed again, I said XXXX with it.

I have an orange/black topped suction pump I bought from Autozone for $10 and every time I changed my engine oil I would run the suction hose down the dip stick tube and suck out all the fluid I could get....between 1 and 2 qts. I carefully measured what got out and replaced with ATF+4 which I know has synthetic oil in it. Every bit I got out I analyzed for condition of oil and it was usually pretty clear with no burnt smell. I pull a boat and stock trailers occasionally.

I will probably never change those fluids in this truck and probably die before I put 100k on it.

That is how I do it.

Mark

OT Auto Tranny Fluid Change

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