Transmission servicing revisited

[Roger]

I’ve read the various posts about is it better to flush than dropping the pan method. It seems like the flush method is the preferred one. However, I’ve been advised that you should switch back and forth, because it is wise to drop the pan and clean the filter every other time (Prior Service advisor who has now moved on to his own dealership in another state). What’s the feeling towards that? I’ll be taking my 01 in for servicing on Tuesday and last time I had the flush method done. I like to know what my fellow Silverado owners prefer and why.

[ken1mod]

Gentlemen,

 

Changing the filter is CRITICAL. Besides, what sort of hairballs from the previous flushee are going into your transmission? I really doubt that they are going to flush your trans with 20 quarts of premium new fluid.

 

Just do what the manufacturer wants. drain the pan and replace fluid regularly.

 

Just exactly how do these flushing machines work anyway, does anyone really know. No manufacturer recommends flushing.

 

Ken

[fossil]

You don't need to flush as long as your regularly change the trans fluid and filter. Even with a flush, I would hope that the filter gets changed after the flush or else you just wasted your money.

[rmreid]

Large Chevy dealership here in Western TN routinely does tranny power flushes and only changes the filter on request by the customer.

Not being a mechanic I aksed them why They said that by doing the power flush it gets all of the old tranny fluid out where a pan drop does not.

[pm26]

If you change the transmission fluid and filter often, you do not need to "flush" it. Seems to me that flushing is for those who have had their original fluid and filter in their transmission for 10 years/150k miles.

[fyarbrou]

You had better watch doing a flush. Yes, it does remove all of the gunk that is built up in the transmission. Sometimes that is not a good thing. An old transmission pro told me that you are far better off to introduce new transmission fluid gradually in a higher mileage vehicle.

 

Sorta like running is good for you. If you have not exercised in a few years it would not be good to go and attempt to run a marathon.

[C & A s Dad]

Why flush machines? This is an easy question to answer. The flush method can generate a lot of easy and quick $s for a service dealer. Think about it, hook up a machine in ten minutes or less, let it do it's thing for 15 to 20 minutes at the most and hand you a nice ticket. The technician has not gotten dirty, has not gotten under the vehicle and it has not been put on a rack. He can also be performing other jobs while the machine is running.

 

With that said, there is nothing wrong with using a flush machine as long as you still drop the pan and change the filter. A filter cannot be flushed, it is that simple.

 

I am employed in a closely related industry and for the most part it is about turning the $ out of the bay.

 

For those doing it yourself, there is a very easy way to completely flush your trans yourself. Simply drop the pan, change the filter, replace with the amt of fluid you drained and then locate the cooler lines. This part takes two people. Disconnect the cooler lines that rtns to the trans. Hold a clear glass container under it and have someone start the truck. Pump our one qt which will take only a few seconds. Add one qt of fresh fluid. Pump out another qt and replace a qt. You will need to do this apprx 10 times depending on your trans capacity. If you want blow by blow details, go to Amsoils's website. By the way, I would stongly suggest a premium syn fluid such as Amsoil.

[RyanZ71]

There are those on here who are concerned about the possibility of the flushing machine re-introducing junk into the transmission. That doesn't happen, those machines have several filters of their own which get changed and serviced.

 

A flush will be just fine as long as it is done right.

[ken1mod]

Gentlemen,

 

So is it correct that the machine reuses filtered fluid that is used? What if the previous flushee had horrible nearly burnt fluid in it? No amount of filtering will restore additive balance.

 

Gee, no thanks.

 

Ken

[RyanZ71]

The modern machines do NOT reuse the fluid, why would they want to do that? The filters exist on the machines so that any small metals or whatever that may still exist in the pump area do not get re-introduced into the tranny. I think the safest thing would be to visit your local repair shop and have a talk with the transmission expert or tech who does the flushes and express your concerns with them before deciding upon a flush, that should give you some peace of mind

[ken1mod]

thanks ryan

 

ken

[100R1]

Power flush a "JUST REBUILT" tranny to flush any metal patricles out of the lines, cooler, valve body, converter etc.

 

but on a perferctly fine running tranny, Drop the pan (add a drain plug if not so equiped) change the filter add fluid to top off to correct level. Then drive for a week, pull the plug drain & re0fill to proper level.

 

The theory behind no power flush on a tranny running OK with some miles and time between fluid changes is that the power flush could knock loose metal shavings and not fully remove them, the shaving could then get caught someplace like the valve body, converter etc.

 

also power flushing a high millage tranny that has not had any service in it's life usually will cause rubber seals to start leaking.

[RyanZ71]

FYI it is NOT a high pressure flush they are doing.

[jhm]

Power flush a  "JUST REBUILT" tranny to flush any metal patricles out of the lines, cooler, valve body, converter etc.

 

but on a perferctly fine running tranny, Drop the pan (add a drain plug if not so equiped) change the filter add fluid to top off to correct level. Then drive for a week, pull the plug drain & re0fill to proper level.

 

The theory behind no power flush on a tranny running OK with some miles and time between fluid changes is that the power  flush could knock loose metal shavings and not fully remove them, the shaving could then get caught someplace like the valve body, converter etc.

 

also power flushing a high millage tranny that has not had any service in it's life usually will cause rubber seals to start leaking.

 

<{POST_SNAPBACK}>

 

 

How does adding fresh fluid "knock loose metal shavings"? When done correctly, including changing the filter, a total coolant flush is perfectly safe and beneficial. Where this misinformation comes from about fresh fluid causing leaks is anyones guess, but talk to a tranny expert, someone who actually services them for a living and you will not hear that. Adding just a couple of quarts then driving around is probably worse then just leaving it alone. Go check out the Amsoil site and see why. To each his own but I had a total flush with new filter at 50k and no leaks, no problems. By the way, I wouldn't go to a quick lube place.

[B33tl3]

I dropped off my 2002 Sierra Z-71 for oil change this morning. I asked the guy how much they would charge to change the transmission fluid and filter. He told me he would suggest a flush and if I wanted they filter changed they could do that too for an extra charge. I started grilling him about the flush.

He said that just dropping the pan removes about 5 quarts of fluid and the system holds 12 so you still have a lot of old fluid in there. When they do a flush they send a cleaner through the system through one of the lines like an IV and it drains through the plug. After they have done that they push 16 quarts of fluid in, the theory is that the first 4 quarts will flush out any remaining fluid or cleaners and then you have 12 quarts of clean fresh fluid. After that they add an additional anti-friction agent.

I had him do the flush and new filter.

Charges

Oil Change $14.95

Transmission Flush $99.99

Labor for filter change $50

New filter and gasket $25

 

 

-Beetle