GtStallion51

Not sure where to post this ..... So here it goes anyway. I recently hit the 30,000 mile mark, and I want to replace the transmission fluid (Auto-trans) I was told by one dealer that was not possible because the system is sealed, and they recommended I not break the factory seal unless something is possible wrong with the trans ... in other words they're telling me there isn't any maint. required.

Have any others come across this issue before?

elwhit95

It is a sealed system that doesn't even have a dip stick. From what I have gathered no they do not want to do what you are talking about. I think the owners manual talks about the tran fluid being changed at like 100,000 miles but not before then.

Louie

It is a sealed system because it works under considerably higher pressure than the engine oil. 30k miles is way too soon for a trans oil change if you don't have any problems.

lodom

I don't think 30k is too soon for a transmission fluid change. Just like changing engine oil, fresh fluid will help ensure the life of the transmission, especially if the car is driven hard. Heat breaks down transmission fluid. I'd have it changed every 30k, but you need to find someone that has experience with the 5R55S. I'd call another dealer and see if they'll do it.

AWmustang

If the system doesn't even have a dipstick, I don't think you can treat it the same as you would oil or older transmissions.

There is clearly something different with this Trans.

sook

They say that you need special equipment to change the fluid. There is a hole in the middle of the trans pan drain bolt where they evacuate and inject the fluid. This information comes from the factory service manual. Maybe someone has come up with another way to change the fluid. I personally haven't had to worry about it yet, but this is just what I read.

metroplex

The automatic transmission uses a whole buttload of clutches along with clutch disc(s) in the torque converter for lockup action. I'd say 30k-40k mile intervals are acceptable for the automatics. Unless the 5R55S doesn't generate heat and doesn't use clutches, I'd change out the fluid somehow. A typical automatic will go 100k miles w/o any problems on the original fluid until the friction modifiers all break down and the clutches wear out.

Luckily the TR-3650 manual doesn't suffer from the same problems.

theedge67

My parents '90 Taurus auto went almost 300K miles with no tranny fluid changes. The engine died before the trans. If it can do that in 1990, I have faith that 100K change interval for a better designed tranny and better oil technology is sufficient.

metroplex

They were lucky and in the minority. Even the Police Interceptor's 4R70W, 4R75W, and 4R75E require 30,000 mile fluid service intervals. What happens after 100k miles of not changing the fluid is the friction modifiers break down and the torque converter lockup clutch gets fried. Whenever the TC has to lockup or be commanded to slip, your car will feel like it is running over rumble strips. After awhile, the internal clutches in the trans will also fry due to inadequate friction modifier content.

I'm skeptical about the 5R55S NEVER needing a fluid change, but hey, it's your car. I went with the TR-3650 because IMHO, a Mustang GT and a manual transmission were meant to be together.

Giddyup

The Mustang and Automatic were meant to be together for this guy...... I've had e'nuff of leg cramps in stop & go traffic in my lifetime. Free hand is nice too.....

theedge67

I'm sure if the transmission needed a fluid change at 30K to keep it going, Ford would have recommended that since a very good majority of owners would have gone to the dealer for that service, hence making more money. Why would they intentionally deceive us so as to harm the transmission? It's not like transmission service intervals are a big selling point or anything, they wouldn't sell less cars if the interval was at say...50K instead of 100K. Nobody would notice until they got the car home.

I would think that the Police Interceptors transmissions WOULD need to be serviced at 30K, they have a TOUGH life...I know, I drive one every day. We put those cars though HE11! Imagine jumping in the car when it is -5 outside and it's been not running for 3 hours, (or 3 days on some occasions depending on the car) screaming out of the parking lot lights and siren and running full steam squealing tires around corners WOT, stop signs, constantly changing gears...you get the idea. This kind of thing happens daily for the average city police car. The average non police vehicle has maybe .1-.5% of it's life dedicated to WOT runs, while a police car may spend 5-10% on WOT runs.

theedge67

I'm sure if the transmission needed a fluid change at 30K to keep it going, Ford would have recommended that since a very good majority of owners would have gone to the dealer for that service, hence making more money. Why would they intentionally deceive us so as to harm the transmission? It's not like transmission service intervals are a big selling point or anything, they wouldn't sell less cars if the interval was at say...50K instead of 100K. Nobody would notice until they got the car home.

I would think that the Police Interceptors transmissions WOULD need to be serviced at 30K, they have a TOUGH life...I know, I drive one every day. We put those cars though HE11! Imagine jumping in the car when it is -5 outside and it's been not running for 3 hours, (or 3 days on some occasions depending on the car) screaming out of the parking lot lights and siren and running full steam squealing tires around corners WOT, stop signs, constantly changing gears...you get the idea. This kind of thing happens daily for the average city police car. The average non police vehicle has maybe .1-.5% of it's life dedicated to WOT runs, while a police car may spend 5-10% on WOT runs.

theedge67

Darn forum gremlins decided to triplicate my post...

TombStone

Read the article in the Jan 06 issue of Modified Mustangs. They wrote a good piece on automatic trannies (part 1 of many to come). It should answer many of your questions. Probably wouldn't hurt for the manual guys to read also. Very informative and dispells many myths manual guys have about our trannies.

Louie

Maybe this can help (instructions from the service manual):

metroplex

I don't get that magazine. I have an AOD and two 4R70Ws. We used to have a C6 3-speed auto and a Dodge 3-speed auto transaxle.

Ford claims the 4R70W in the E-250 (5.4 2V V8) doesn't need the torque converter drained since there is no plug. Instead, the service manual calls for dropping the pan every 30,000 miles. The reason behind this is to replenish the friction modifiers rather than change the ATF itself. I don't know the EXACT reasoning behind the "lifetime" fills for the newer 5/6-speed automatics, but there's a good chance Ford uses a synthetic ATF and assumes people will throw out their cars after 5 years.

MustangGuy

I'm with you kevin.

keeper

I am not sure I want to know what you need that "free hand" for...

YardSpecial

I would say if you drive it hard, change it at 50K mile.

Not buying the 100K change outs............

dave_bought_another_black_stang

It was part of the 30K service recommended by ford that I had done at 33K as I was getting ready to drive from Jax FL to the Bay area in CA. The piece of mind was worth it.