Transmission Additives

I’m sure this question has been asked a million times, but I have a 97 Deville with 120+k miles. When I first start the car and drive, the tranny slipps and revs going from first to second gear. After it does this once, or in the first 30 seconds of driving, the tranny is smooth as silk. This problem did not start until after I had all the fluid dynamically flushed at a Pep Boys. I figured getting modern and fresh fluid in the tranny would be a good thing. What could the problem be and is there an additive that could resolve the issue.


You don’t need an additive. You need to have the filter (pickup screen) changed and to make sure that you have the correct transmission fluid and it is at the correct level. I would never go to PepBoys for any kind of work, only to get parts. Find a good independent shop with transmission experience. Don’t go to one of those national transmission chains.

This problem did not start until after I had all the fluid dynamically flushed at a Pep Boys.

No more flushes. You change the fluid on a regular bases along with the filter. Right now you need a new filter. They do a “flush” because it makes them more money.

OK How long has it been doing this? How many miles are on the transmission? Has it had prior fluid changes? What prompted you to get the flush? Was it maybe just beginning to have a problem? Transmission fluid changes are properly done to prevent problems, they seldom fix a problem.

The filter/screen was changed a couple years ago…probably 4 years ago when I bought the car and changed ALL the fluids…inclidung flushing the braking system, radiator etc. At that time, I just had them drop the pan which only removes perhaps 1/3 of all the fluid in the tranny system. I wanted to change all the fluid because of the milage on the tranny. This was a passive flush, ie they add fluid at the same rate they drain it, as opposed to the pressure flushes that I heard about. I specifically asked them about that because I did not want a pressure flush. I am a BIG believer in having fresh fluids in a car to prevent big problems like bad calipers, water pumps, braking cylinders etc. This is why I had it done. I do not intend to flush it again for it is simply not necessary at this point. I really cant say whether they changed the screen at that time. My old mechanic told me it might be a seal that is worn and once the system pressurizes that stops the slip. Only happens once at cold start up then its fine.

DONT EVER, EVER let anyone flush your transmission without dropping the pan and changing the filter. This is absolutely necessary. These small shops are reaming the general public with their flush machines. They are making their quick buck off of you and putting your transmission at risk. You cant imagine how many transmissions cross my bench on a monthly basis due to improper or lack of servicing. The companies that produce and sell these flush machines sell them to the small shops and tell them how quick they can make money with them. You can not properly service an automatic transmission by just flushing it and not dropping the pan and changing the filter. They should not be allowed to sell these machines to any shop. ONLY qualified transmission techs should be the ones to be able to purchase such equipment. Unfortunately, you have an expensive lesson heading your way.


I’m going counter to transman on this one. I’ve done my initial and 2nd pan drops and found little to clean up. Now the filter could be in question, but many don’t even have one. They have a mesh screen like the older automatics (60’s and 70’s) had. The filters themselves are usually in the 100um range which is in the visible range and surely capable of just sinking out in the pan.

But…by all means, test transman’s theory and have the filter changed to correct your 1-2 flare. Buy a magnefine and install it in the cooler circuit. That should keep everything clean from here on out.

Today, there are about 10 different types of transmission fluid. Do you know FOR SURE what type the machine pumped into your car?? Do you know FOR SURE what type of fluid your tranny takes?? Between 1988 and 2000, the Cadillac Division used an amazing number of different transmissions. Getting some of the unique internal parts for these transmissions (the shift solenoids) has become difficult if not impossible…When yours fails, (it won’t be long) the repair cost will exceed the value of your car… That’s just the way it is today…

When yours fails, (it won’t be long) …/… That’s just the way it is today…

A shining beacon of optimism!! So confident …so assured… LOL!!

No, I am not sure what kind of tranny fluid they put in, outside of it being a name brand…valvoline, penzoil etc. If I am not mistaken, when you look at tranny fluids on the shelf, they all say compatible with all transmissions these days. Now that is not to say that each mfg might add a little bit more of this or that in theirs so they can claim it is unique. Also, when I had the screen replaced a couple years there wasnt anything there and that was after 110k miles. Since I have only driven the car perhaps 10k miles in the last 4 years, I cant imagine the screen would need to be replaced again.

I also do not understand how a passive tranny flush can hurt. You are simply adding fresh oil as you drain the old oil. Nothing is pressurized, the engine simply idles as this process occurs for the most part. I believe they did run it through all the gears to get the oil out of where ever it is through the different gears. How can a passive flush hurt?


If this procedure was done–as is typical at a place like Pep Boys–without first changing the transmission filter, then the debris in the old filter was likely forced out by the flush and this debris may have found its way into the incredibly tiny passages through which the transmission fluid is supposed to flow unimpeded.

Just a small bit of debris in the wrong place can REALLY damage a transmission. That is why I would never entrust this procedure to Pep Boys, Jiffy Lube, AAMCO, Midas, Meineke, Sears, Monro, etc. Servicing of a transmission should only be done by an independent transmission specialist, IMHO.

Also, regarding your statement:

“when you look at tranny fluids on the shelf, they all say compatible with all transmissions these days”

That is most definitely NOT true. Each type of transmission will have a specific type that it needs, be it Dexron, Mercon, ATF+4, Honda-type fluid, etc. Using the wrong type–which is also very commonplace at places like Pep Boys, Jiffy Lube, etc–will lead to very poor functioning of the transmission and ultimately will damage the transmission.

But they didnt drop the pan and change the filter. Thats sheer laziness. More and more of these shops buy these flush machines because they are so easy to use that any kid off the street can flush a transmission. In fact, most of these small shops hire kids off the street to do this. They hook up this easy to use machine, flush the trans, disconnect machine then drain your wallet and send you out the door saying they serviced your transmission. But guess what, there is still trash in your pan and in your filter. Yea, you got 98% of your fluid changed but theres still trash in your transmission with an old filter still in there. THEN two days or two weeks later when your transmission starts acting up and you bring it back to them because they just did a “Complete service” (Yea right) on your trans you get a bunch of dumbfounded looks and shrugged shoulders because they dont know whats wrong with your trans, and since they dont know the innerworkings of an automatic transmission they send you down the road to a transmission shop to see the big boys who can fix this complicated piece of machinery that they dont understand and have no business even touching in the first place. Nobody but a qualified transmission tech should be touching an automatic transmission.


Transman is 100% correct. About a year ago my youngest son who lives in another city took his Aviator in to the Ford dealer for a trans service.
(No codes present and only an occasional and near unnoticeable 2/3 shift flare.)
He got a vehicle back in which the trans would buck a person out of the seat. “Normal” according to the service writer, who slso stated that the trans fluid would have to “break itself in” along with several other off the wall statements. Please.

This led to my going down there and having a go-around with the service manager, who did admit the service writer was full of carp. (sic)
This service manager also stated that they used the “approved procedures” and had not dropped a transmission pan in 15 YEARS! It was flush only. Needless to say, I told him they’ve been screwing up for 15 years and also asked if they changed engine oil or fuel pumps without changing the filters. No answer to that one.

So 3 days, a pan and valve body drop, and several more flushes later the transmission was finally shifting like it should.

I don’t have a problem with flushing at all but it should be used in conjunction with a pan drop and filter change (if applicable); not as a stand alone service.
In regard to that “approved procedure” the service manager referred to, neither he nor Ford Motor Company itself could or would back that statement up.
My emails to FOMOCO only got a canned response of revisiting the same dealer who “has all of the proper equipment and factory trained technicians to take care of any problem”.
No response from Ford when I asked why should the same clowns who botched this be entrusted to fix it. :wink: