General Automatic transmission question

[DMC3165]

I recently acquired a low mileage 03 Chevy impala. The car is in fantastic shape overall. Some minor issues with the cooling system but other than that it is literally like a brand new 13 year old car.
My question is I'm going through the car and want to change all the fluids. The recommended service interval for this particular transmission is 50,000 miles. The car currently has 41K. There seems to be a lot of mixed opinions on changing the fluid or leaving it alone. Since its under the recommended service interval it should be ok. But I know it was generally used for short trips and up until last week probably never left the Tampa Florida area it's entire life. Fluid seems nice and red and no issues at all. Just like being proactive with maintenance. Thoughts?

[PJ Grady Inc.]

I'd say change it. It's when it smells burnt that you risk finishing it off with a fluid change. If you wait too long you lose that maintenance window that you should still be within.
Rob

[DMC3165]

Thanks Rob. Changing it was my gut instinct. I may let the local Chevy dealer due it. They get $230. For it and they flush out the old stuff rather than just dropping the pan and filter. I always hated servicing automatics myself anyway.

[Farrar]

Received wisdom is that you should change the fluid on schedule, but don't let any shop guy sell you a "flush" unless you've been having problems.

Hm, that reminds me, it's time for my 100,000-mile transmission fluid change ... Thanks! :)

[DMCVegas]

Received wisdom is that you should change the fluid on schedule, but don't let any shop guy sell you a "flush" unless you've been having problems.

Why wouldn't you want to change out the fluid? I mean, unless it's a car you're trying to unload onto someone, don't ever add any sort of additives, sure. But hydraulic fluid does break down, and given that it is hydroscopic can cause delayed shifting problems as the water content within it is compressible. Just like a brake line.

Now if the fluid is burned like Rob says, yeah, there is a possibility that standard detergents can knock already damaged friction material off. So you're in for an unavoidable rebuild either way.

[Farrar]

Why wouldn't you want to change out the fluid?

Please re-read my post. There's a difference between a change and a flush.

[DMCVegas]

Please re-read my post. There's a difference between a change and a flush.

http://media4.popsugar-assets.com/files/2013/07/31/693/n/1922398/37440dc8fd59db0b_wuse1z.xxxlarge/i/When-He-Said-Quit-Isnt-Way-We-Roll-NYC.gif

I give up. How you you change all of the fluid inside of a transmission system without flushing it?

[Michael]

I give up. How you you change all of the fluid inside of a transmission system without flushing it?

The two services are quite different.

One is simply a drain and refill, maybe drop the pan and change the filter if possible. This gets about 80% of the fluid. The other requires fluid or sometimes special cleaner being injected through the cooler lines. This is a debated service that a lot of techs say is not necessary and can damage your transmission.

[DMC3165]

My understanding of a flush was that they run fresh transmission fund through the collateral lines into the unit until all the old stuff was out. Not any sort of detergent or other materials.

I recently spoke to someone about changing the fluid myself and they said to take the cooling lines off the radiator and run the car until fluid stops coming out and that removes about 98% of everything in the transmission. But screw that up and you'll burn up the pump.

It seemed reasonable to let my local Chevrolet dealer due it and not a third party shop. But since I still have a little while to think about it. I'll just run it for a little bit first.

[Farrar]

Thanks, Michael, for explaining the difference.

I'll buzz off now.

[Michael]

If you really want to flush the trans, the safest way is do what I did. Just drain and refill 3 or 4 times over a 500 to 1,000 mile window. Seriously you can do this without even jacking the car up.

I did this during the testing phase of my filters, and ended up putting over 1,000 miles on the prototype filter and during this I dropped the pan for the prototype replacement, and inspection a few hundred miles later, as well as dumping and inspecting the fluid even later on. I figure 3 fluid changes with some mileage in between should effectively "flush" all the old out.


I recently spoke to someone about changing the fluid myself and they said to take the cooling lines off the radiator and run the car until fluid stops coming out and that removes about 98% of everything in the transmission. But screw that up and you'll burn up the pump.


I would fall into that catergory that is against power flushes and I sure as hell wouldn't run the trans dry EVER! Even at idle, the transmission needs fluid. The 4141 is quite possibly the worst transmission ever made. It just wants to break so you have to be gentle with it, that means a complete stop and rpm drop before going to park, drive, reverse, etc. They are very unforgiving so blasting high pressure fluid through the lines and running them dry is something that you shouldn't risk. My way is a bit extensive and possibly excessive, but it's safe.

PS: if you follow Dave Swingle's service method (and one that I like) just dump and fill the fluid at every oil change. You are right there so what is it to remove one more drain plug and pop in 4.5 qts of ATF?

At every 15k, drop the pan and change the filter.

[PJ Grady Inc.]

My understanding of a flush was that they run fresh transmission fund through the collateral lines into the unit until all the old stuff was out. Not any sort of detergent or other materials.

I recently spoke to someone about changing the fluid myself and they said to take the cooling lines off the radiator and run the car until fluid stops coming out and that removes about 98% of everything in the transmission. But screw that up and you'll burn up the pump.

It seemed reasonable to let my local Chevrolet dealer due it and not a third party shop. But since I still have a little while to think about it. I'll just run it for a little bit first.

Yes a flush pumps in new fluid to replace the old which is the only way to replace all the fluid. Solvents are not typically involved. There is no other way to drain the converter other than drilling a hole in the housing (after R&Ring the trans. to access it) and that typically traps a quart or more of dirty fluid. You're doing the right thing...now lets just hope I didn't jinx you by saying so!
Rob

[DMC3165]

Yes please don't jinx it!

[David T]

On newer cars it is recommended that fluids be flushed. This means the power steering, coolant, and transmission. Each one is separate and requires a different machine. Because of the longer service intervals it makes flushing necessary. If you stick to the recommended service intervals for the older cars, flushing is not generally required. Flushing can become necessary especially if you are "resurrecting" a sleeper. The drain and refill method is wasteful and inefficient but it can work. Better to have it flushed in a shop but there can be problems. If the transmission is REALLY dirty and the fluid is all dark and smelly you run the big risk of breaking loose an avalanche of debris which will plug things up inside. In some cases it is better to leave well enough alone. It is a judgement call. The pros and cons should be decided on an individual case basis with the shop. In some cases the drain and refill may be a better way to slowly clean the transmission. Stay away from additives, sealers, and cleaners, they will only aggravate the problems. The filter must be either replaced or disassembled, cleaned, and reassembled. Don't forget the gear oil in the final drive, it is separate on the automatic. Whenever servicing the auto trans you should inspect the wiring harness for damage and security away from the exhaust and all of the external On-Car adjustments. As a general rule on older cars if you don't know what kind of fluid in in there or when it was last changed, it is time to replace it. Fuel is no good after 6 months, brake (and clutch) fluid after 2 years, anti-freeze after 5. Motor oil should be changed annually. Transmission fluid based on condition.

[DMCVegas]

Yes a flush pumps in new fluid to replace the old which is the only way to replace all the fluid. Solvents are not typically involved. There is no other way to drain the converter other than drilling a hole in the housing (after R&Ring the trans. to access it) and that typically traps a quart or more of dirty fluid. You're doing the right thing...now lets just hope I didn't jinx you by saying so!
Rob

That was precisely my understanding as well. The flush pumps out all of the fluid, but it's just regular ATF (or whatever specification you use) and has absolutely no additives. If simply replacing fluid were to cause problems on old transmissions, that would mean that when draining a pan in order to replace a filter, you'd have to catch all of the old dirty fluid and put it back in to avoid a problem. 80% versus 100% doesn't make a difference at all.

I've done the transmission flush before with a vehicle, then waited 2 weeks and replaced the old filter. Even after just the initial flush the truck shifted better.

Flushing an automatic transmission doesn't cause any problems in itself. Mechanic in a Bottle additives are what will cause problems. Existing damage not withstanding of course. Because if you've got a transmission that's already on it's way out, flushing isn't going to help at all. The irreversible damage is already done.

[DMCVegas]

...anti-freeze after 5.

That however depends upon the anti-freeze and the design of the cooling system. DEX-COOL comes to mind. DEX-COOL is *supposed* to be good for 150,000 miles. BUT that is only if it remains clean and uncontaminated. GM has had lawsuits over this in the past. If you have a vehicle that has an overflow bottle attached to the radiator where it is vented to the atmosphere, dirt and grime gets in, contaiminates the coolant, and will subsequently cause premature failure of the coolant and the cooling system when the dirty fluid gets sucked back in.

However, if you have a sealed system with an expansion tank like the DMC-12 uses (which Ford also seems to have adopted for their vehicles) the coolant remains sealed and is protected from external dirt. So you can reach the 150,000 limit on extended life antifreeze with no problems. But still, keep an eye on that fluid.

[Michael]

Only DeLorean owners will put 200 bucks down an AutoArt DMC-12 scale model without batting an eyelash or throw 100 bucks away on a raffle ticket for just a chance to win a car, but when it comes to spending an extra 25 bucks on 5 qts of ATF or 20 bucks on a few gallons of coolant...then we start splitting hairs.

Just an FYI, A new Auto transmission is almost 6 grand plus labor.

[DMC3165]

The only problem I've seen with the transmission I was posting about originally is problems that arise from power flushing at a shop. If there is any metal in the Trans power flushing from the coolant lines has a tendency to jam those particles into areas where the internal pump wouldn't and this can cause damage. I think I might just drop the pan change whatever comes out and due it again in another 10K miles.

[DMCVegas]

Only DeLorean owners will put 200 bucks down an AutoArt DMC-12 scale model without batting an eyelash or throw 100 bucks away on a raffle ticket for just a chance to win a car, but when it comes to spending an extra 25 bucks on 5 qts of ATF or 20 bucks on a few gallons of coolant...then we start splitting hairs.

Just an FYI, A new Auto transmission is almost 6 grand plus labor.

Actually...that IS a very valid point. Not accounting for the fluid drain that goes along with every time you replace the filter, just dumping out the fluid at least every-other oil change would be much cheaper than the flushes, and would keep fresher fluid in place to where they wouldn't be needed at all. And that would be speaking for any vehicle out there.

[DMCMW Dave]

Only DeLorean owners will put 200 bucks down an AutoArt DMC-12 scale model without batting an eyelash or throw 100 bucks away on a raffle ticket for just a chance to win a car, but when it comes to spending an extra 25 bucks on 5 qts of ATF or 20 bucks on a few gallons of coolant...then we start splitting hairs.
.

I don't think it's the same people.

[PJ Grady Inc.]

Actually...that IS a very valid point. Not accounting for the fluid drain that goes along with every time you replace the filter, just dumping out the fluid at least every-other oil change would be much cheaper than the flushes, and would keep fresher fluid in place to where they wouldn't be needed at all. And that would be speaking for any vehicle out there.

I agree that with more frequent changes you negate the need for flushing but some of the newer cars require it as the only means of changing the transmission fluid possible.
As for coolant change intervals on a Delorean I would go with every two or three years....not five as has been suggested in an earlier post.
Rob

[DMCVegas]

I agree that with more frequent changes you negate the need for flushing but some of the newer cars require it as the only means of changing the transmission fluid possible.
As for coolant change intervals on a Delorean I would go with every two or three years....not five as has been suggested in an earlier post.
Rob

Agreed. 5 years is for extended life coolant. Which unless you have a car made for it, you're using the regular green antifreeze which is 2-3 years.

Thank you for clarifying that.

[David T]

Agreed. 5 years is for extended life coolant. Which unless you have a car made for it, you're using the regular green antifreeze which is 2-3 years.

Thank you for clarifying that.

I have not seen any problems going to 5 years on the coolant as long as it is tested every year for ph and strength. That's with the green Prestone. If it starts changing color, the ph goes acid, or the strength gets diluted it should be flushed and changed. All too often regular changes and inspections are a moot point, few owners do it. About the only time they will change the brake or clutch fluid is when they see it on the floor! Who checks tire pressures? That should be done monthly at least! 5 years on the coolant is also considering a car that gets some use. If it is just sitting the coolant can go bad sooner.

[DMC5738KC]

Can anyone tell me which solenoid goes in which side of the transmission valve body. I was installing my rebuilt shift govenor and thought I would pull the solenoids to make sure they were unobstructed and then realized I didn't pay attention to which one goes in which hole! I noticed that one has clear insulated wires and the other one has solid insulated wires. Help!

[David T]

The solenoid with the clear wires goes into the position nearest the manual valve. Refer to G:06:02 1st column under NOTICE: