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Discussion Starter #1
i've been thinking of having my trans fluid changed on my '03 it has 79,000 mi. on the odo. i've heard pro's and cons. what are your thoughts? is it a good idea or should i leave well enough alone? thanks in advance for your input.
 

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Personally I see nothing wrong with doing it early. Its a time consuming, dirty process but worth the effort. There is alot of clutch material that is floating around in the fluid which may increase clutch wear since the fluid is now abrasive and not clean. The viscosity of the fluid has been reduced with that many miles and things will just work smoother with clean new fluid. I say go for it
 

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There are no cons to changing your transmission fluid. There are cons to having your transmission "flushed" by a machine and I wouldn't recommend that.
 

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There are no cons to changing your transmission fluid. There are cons to having your transmission "flushed" by a machine and I wouldn't recommend that.
Done it to both my vehicles. Never had a problem. :huh:


We flush Transmissions all the time at the shop
 

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Manual or auto? I change the manuals in the fleet about every 30k and the autos around 50k, even if the manual calls for less frequent changes. The manuals get driven really hard, hence the added changes. It is phenomenal how much fresh fluid reduces your shift effort. It gets harder and harder over time and you don't notice it. *knock on particle board* I have never had to replace a transmission that in a car that I bought with less than 75k on the clock.
 

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Done it to both my vehicles. Never had a problem. :huh:


We flush Transmissions all the time at the shop
Transmission Flush Problems
While the process of transmission involves thorough cleaning of the transmission and the engine, there is much of a debate whether the transmission flush is safe and actually helpful and whether there are any major transmission flush problems involved. Theoretically, transmission flush is supposed to clean the transmission thoroughly, while the engine oil change is performed. It is agreed that transmission flush does remove a significant amount of the older fluids but it fails to clean it thoroughly.

This way, there are chances that the older fluid might get mixed into the newer one, to dilute it. As a result of all this, the new transmission fluid is always on the verge of a potential damage and falling short of performance. Transmission flush machines involve force and high pressure in the transmission, that can block the valves of the engine by the force of the large chucks that are removed by flushing. These large chunks are actually the remnants of the older engine fluid, that can block the shifting of the transmission and also lack of lubrication
source

Flush machines do what they say; they force high pressure cleaning solvents back through the engine and
transmission and clean out some of the accumulated junk that has formed. Now engines have small passages and galleries through which oil or automatic transmission fluid flow and there are one-way valves that keep the fluids from backtracking for whatever reason. By using an aggressive cleaning procedure like flushing, large chunks of accumulated sludge are broken off and forced backwards through these galleries and valves and, more often than not, lodge tightly and block them. This cuts off the normal flow of the fluid and causes lack of lubrication in an engine and abnormal or no shifting in a transmission. The results are expensive repairs, or more often, engine or transmission replacement.


But who actually recommends that it be done? I checked with GM, Ford, Chrysler, Nissan, Honda and several other new car manufacturers and not one recommended an engine or transmission flush as routine maintenance. In fact, they specifically don't recommend it at all!! The new car dealerships that do sell them use the implication that since they are the dealer that it must be the factory that recommends it. And if they do say the factory recommends it, they are flat out lying to you.
source



On top of the quick info posted above I've had three friends need transmission rebuilds after having them flushed. My transmission guy , who I trust and is very good, also said never get that done.

As with anything I was offering my opinion, nothing more.
 

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I have 193K miles on mine and have changed the trans fliud three times. I can tell a difference each time I change is as it shifts smoother after the change. Make sure you use correct the recommended Dextron III fluid. It is tough to find at the auto parts any more they hav all dislpaced the Dextron III with Dextron IV but there are different additives in it for the different type of trans seals in the newer Corvettes. You can get the Dextron III from the GM dealer by part number.
 

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Discussion Starter #9
my tranny is an automatic, thank you all for your input it's been most helpful. i will change the fluid but i'm not going to get it flushed. i was'nt going to flush it anyway, just change the fluid.
 

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The transmission "flushers" I've seen are just glorified "fluid exchangers" and use the cars normal operation to change all the fluid , which won't hurt a thing.
All they do is drain and refill
You run the car , the trans pumps the fluid out and is refilled through the low pressure side.
Nothing can be dislodged that isn't going to come loose anyway since the trans is actually puming normally.
The guys who have a failure after doing a flush of this type would have had a failure anyway

If you use an actual "powerflusher" , then I could see issues developing

Both types are made.

I made my own "exchanger" and have never had an issue
 

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The only thing I would flush is the cooler and cooler lines, and I would back flush it. There are 0 cons to back flushing your cooler and lines.

Backflushing your cooler/liines will allow your cooler to work more efficiently and prevent a lot of debris from re-entering the transmission. The cooler has a tendency to accumulate a lot of debris from the fluid.
 

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Whatever you use is your choice, don't make the mistake of thinking that Dexron VI is better than Dexron III for manual transmisisons. The friction modifiers are different and Dexron VI is not suitable for manual transmissions. That is why GM came out with PN 88861800 for manual transmissions and transfer cases.

The specs may say Dexron VI is backward compatible with Dexron III, but that is for automatic transmissions, and may not be the best choice for a manual transmission where you have gears and synchronizers instead of clutches and a torque converter.

My .02....
 

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Thanks Raid. I was looking for this earlier. :thumbsup:
 

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I made my own "exchanger" and have never had an issue
How did you make your setup?

This is something I've been wanting to do, but haven't had the time to research it.
I had a Durango I put an auxiliary trans cooler on and was going to make some sort of exchanger since I had the cooler lines disconnected, but time ran out.

Thanks,
Rich
 

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used a jerry can for filling and a bucket for draining.
just put the can high and connected a hose and then connected a hose to drain in the bucket.
start the car and the car does all the work
 

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used a jerry can for filling and a bucket for draining.
just put the can high and connected a hose and then connected a hose to drain in the bucket.
start the car and the car does all the work
Simple enough.
I tend to complicate things sometimes and miss the simple solutions.

Thanks,
Rich
 

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there is a filter in my 98 A4

When I changed the fluid in mine, I dropped the pan and changed that filter. Unfortunately, it is enclosed in a plastic chamber, so I couldn't see how dirty it was and thus if it was really that necessary to be replaced.

As someone stated earlier, it was a very messy job. Also, the two bolts closest to the exhaust pipe broke off as I was trying to remove them, got only one replaced.

Owing to the fact that dropping the pan only drains the fluid that is in the pan, I reinstalled the pan, refilled with new fluid and ran the engine and shifted the trans thru reverse and drive several times to pump the new fluid thru the whole system and then dropped the pan again. I kinda figured that this procedure would have replaced about 3/4 of the fluid in the system. Perhaps this was overkill?
 
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