MTM2005C6

Has anyone heard the commercials for Aamco's power flush for tranny fluid?

Thoughts??????

rhneff

Haven't heard the specific commercial, but in general all such services are neither necessary nor beneficial. The purpose of a "flush" is ostensibly to remove any contamination present including "old dirty" fluid, makes sense in some cases for the engine but an automatic tranny is a sealed hydraulic unit and if there's any "contamination" present to flush out it means it's already too late and the flush job will most likely just make an existing problem worse. Transmission fluid doesn't get dirty unless it's contaminated by clutch or converter damage. IMHO if the tranny's okay you're better off with a regular fluid drain/replacement (including a new filter and pan gasket) and if it's not a flush job won't help.

jefft84

The benefit of the "flush" or fluid "exchange" is not about contamination, but to completley change the fluid from old degraded fluid,to new fluid with the proper amount of antifoaming, anti rust, and friction modifiers. The flush machines are desinged to exchange 1 quart old for 1 quart new so that all the fluid is replaced (aprox 90%) not just the 5 quarts in the pan. I am not saying that dropping the pan and changing the filter is no longer neccesary but why would you only change 30% of your engine oil? is your transmission that less important?

jackdaroofer

But!

While I haven't seen any posts in the last few years, there were a rash of posts two or three years ago where people who did this experienced problems because the flush and new fluid broke loose embeded crud which then blocked internal passages

I did the complete flush at 75,000 and now do the pan and filter only at around 30,000

Corvette Kid

Just curious, what are they charging for this service? It can a beneficial treatment when warranted but you can do it yourself. I just submitted a DIY method (to tech tips) for tranny flushing but it hasn't appeared yet. I believe it to be a better, much safer method than a power flush. Keep checking, it should be there soon. It is titled "Automatic transmission flush-DIY", or something close to that. I think the flush is warranted when the fluid has been neglected and is very contaminated, as in no longer red (or blue for mine) and smells bad! No automotive fluids last forever and many stated change intervals are way too long in my opinion.

jefft84

While I haven't seen any posts in the last few years, there were a rash of posts two or three years ago where people who did this experienced problems because the flush and new fluid broke loose embeded crud which then blocked internal passages

yes very true neglected systems can be held together by crud and flushing them can create problems from washout of buildup.
Personally I recommend the filter every other flush service.

jefft84

The average flush done in my shop is 85-95 bucks including 12 quarts of fluid.
As far as safe the "POWER" is misleading the equipment is run off 12 volts and the pump is actually run of the transmission pumps pressure.
Contrary to your above statement when a car comes in with very dark, burnt, dirty fluid we do not recommend any fluid service untill the transmission is fully checked by a transmission tech, due to the high rate of failure after service.
fluids dont last forever

chriswtx

With everything he says.. Same deal at our shop. Except our machine flushes 16 quarts through the tranny.

"The average flush done in my shop is 85-95 bucks including 12 quarts of fluid. As far as safe the "POWER" is misleading the equipment is run off 12 volts and the pump is actually run of the transmission pumps pressure. Contrary to your above statement when a car comes in with very dark, burnt, dirty fluid we do not recommend any fluid service untill the transmission is fully checked by a transmission tech, due to the high rate of failure after service."

Corvette Kid

So still then, a do-it-your selfer has nothing to lose but the price of the fluid. I've heard the failure after fluid change BS throughout my 30+ years in the car and truck repair business but don't know anyone to whom it has actually happened. I say if it did, it was going to go out anyway.

dodsond

For the 85-130 buck flush job, I doubt it is with synthetic...THe shops around me charge that rate with normal fluid. Shouldn't this be getting flushed with 12-16 qts of synthetic?

Corvette Kid

I'm sure it's not. Yes, if you are going to run it then flush with it. You don't want to know what it cost me in fluid for my flush, at six bucks a quart!

runner140*

I agree. I had mine done last Sunday. The fluid hadn't been changed
in years.

jefft84

Yes the differance is if a shop changes the fluid or flushes it and the thimg goes haywire afterward now its the shops problem in the eyes of the customer. Even if you tell them the possibility of failure after flush in court you as the shop the "professional" and should have known better the customer is "uneducated genereal public" who cant make the right decision. So replacing the trans is on you if it fails. I have seen transmissions fail after flushing and after just fluid/filter service at least 10 times so it does happen but they were of the neglected style so it was bound to happen like you said.

rhneff

I have no axe to grind here, but IMO this is a typical sales pitch used by shop owners to "build a ticket" rather than provide the lowest cost service really necessary. First, comparing engine oil with transmission fluid is not relevant - there is no combustion going on in the transmission thus no by-products (carbon/water/acid/etc.) that do in fact contaminate engine oil over time. Second, you're correct that the additives in transmission fluid do wear out but replacing the volume involved in a normal fluid change (pan drop/filter change) is sufficient to adequately replenish those additives - when we did it in my shop, the volume replaced was more like 70% than 30%. My preference was to add a bottle of LubeGard to help with foaming and friction modification anyway. And third, a major issue with flushing rather than draining is the filter isn't replaced - these engine/transmission systems run much hotter than older cars did and that tends to cause the filter element to harden over time, not only making the filter less effective but also potentially inhibiting the flow of fluid into the trans (since the filter acts as the pickup point in the pan). Replacing the filter, every time, is as much a reason for doing a service as changing the fluid itself because if the filter element gets hard and limits fluid flow you can and probably will experience the same problems that result from running low on fluid except you'll never know it until the tranny dies.

If a flush job seems the right way to go, by all means have it done but do yourself a favor and make sure the filter gets changed at least every 25K-30K miles too (I change mine every year!).

jackdaroofer

I'm a "do it your selfer"

When I flush mine, I drop the pan, change the filter, add four or five new quarts, put it all back together and then do the flush, letting the transmission pump supply the "power"

stanco

stay clear of aamco. I didn't and they charged boque dollars for substandard work. I am replacing the trans again after 6 years and s proc 28k miles.