Transmission fluid change

[gr8scott]

Had an oil change at the local lube shop. The guy said, "I noticed you're nearing 60K miles. Has your transmission fluid been changed? We recommend draining and refill at 30K intervals. "

I passed. I've had cars nearing 200K miles that never had their tranny fluid changed -- of course I didn't love any of them like I love the Reatta, so I wonder whether I should do this. Fluid color looks healthy, no bubbling or foaming, level is perfect. What think ye?

[jonlabree]

25,000 miles

[Rawja]

Others with more knowledge than I are sure to weigh in, but I've noticed that all the quickie-lube places now do a "fluid exchange" rather than dropping the pan and changing the filter.

They insist that it's better, but I have my doubts.

I'm sure its better for them (no re-doing leaky pans, no stocking transmission filters).

What's the actual story?

And BTW I generally go about 15K between changes, though my local environs push me towards the "severe duty" end of the usage spectrum.

[D-a-n-i-e-l]

25-30k, I suggest being at 60k to have the fluid flushed and then change the filter. This will ensure fresh fluid through out and it is a good idea to do the filter. If it was not ment to be change they would not have designed it to be accessable.

As far as going 200k+ miles I would say you are lucky, but I have heard from a few people that if you are up to 100k+ and have not serviced the tranny to just leave it.

[Richard S]

Daniel, you are right of course, but most lube jockeys do not treat the pans with the respect they deserve on the theory that their abuses will be cured by the gasket. Fact is that I think a large number of pans that did not leak before filter changes, leak afterward. Does the flush actually run through the filter? If so, I wonder how well it actually cleans it?

[Roadster90]

There is a TSB on the leaking tranny pans....find it reatta.net. Have to be very clean, use a thread locker, and torque retainers properly. I have to do this shortly....been leaking every since I had the fluid changed by a transmission shop.

[Guest Squire Tom]

104k dealer did the flush and car seems to shift smoother and less of a clunk when the lockup engages.

[Barney Eaton]

There are several things to consider when discussing transmission fluid changes.

First, everyone that knows anything about automobile transmissions will tell you the greatest enemy of the transmission is heat. I have seen charts/graphs that

show the life expectancy of the transmission is greatly reduced with high fluid temperatures.

Have you ever considered that the transmission fluid is cooled by a radiator that is running at about 180deg C ?

On a hot day it could be closer to 190. So how hot do you think the transmission is running, when it is cooled by a radiator that is running that hot?

With that said, where you live enters into the equasion.

Second, the transmission is a mechanical/hydraulic assembly.

Anyone that works with hydraulics will tell you they like clean fluid. The fluid has several functions, it operates the hydraulic valves inside the transmission, it cools the transmission, and it carries away any wear particles.

Living in Texas, where it has set high temp records for over 47 days, and several of them have been around 104,

I run a auxillary cooler (the bigger the better) and DO NOT

run the fluid through the radiator. This works in warm climates but not up north. The cooler is now in ambient air, and the radiator does not need to cool the transmission so both are much happier.

The fluid does need to be changed, there is nothing sacred about mileage, but when it starts to look dirty and leaves sesidue on a clean wipe, then there are contaminates in the fluid.

The system being used today by garages is not ideal. They backflush the filter and claim it is clean, they are also assuming that whatever was in or on the filter comes out with the old fluid. I am "old School" and like to replace the filter.

That's enough for now

[D-a-n-i-e-l]

One or two other things I find and even "good" shops do is over tightening of the tranny pan bolts. This happens all the time. A good torque wrench is a must, and not the $25 dollar version. Some things are worth the little extra. Second do not coat the cork gasket or the pan in RTV. May be a small bit in the corners to hold it in place, but that is it. Fel-pro usally give you place holders to help so no RTV is needed.

[Guest NEMO]

there is the trick , tie the gasket with sowing thread then when all the bolts are started,cut and remove,then tighten

[D-a-n-i-e-l]

Great info!!!

[Guest simplyconnected]

In Michigan, our radiators heat the tranny fluid on those cold winter days. God help a cold transmission trying to shift with really thick hydraulic oil. We depend on multi-viscosity engine oil, rich mixtures, heat riser valves, and electric fans that DON'T turn on too early. Tranny fluid rarely (or never) gets changed in most daily drivers, here.

Down in Florida, changing fluid must be done regularly. Heat breaks it down. I have seen where changing fluid restores faulty shifting patterns back to normal. Of course, I didn't believe the dealer when he suggested it. 'Why, that's preposterous. Up north, transmissions dont 'heal' themselves.' Tell you what, the car shifted like brand new after the tranny fluid change, and it was only three years old, with low miles (way too young to be shifting badly).

I always get the kit with gasket and filter, and change at ~40k. On a vehicle that tows; ~25k (in Michigan).

[Lindsaysdad]

I drop the pan and put in a trany filter kit every 60K. Been doing it since I bought my first car in high school. Been having it done by local garages now that crawling under a car is not so appealing and have never had a problem, from the garage or from my tranys.

Dan

[Guest CL_Reatta]

In school we are taught to not even use gaskets. We had a representative from permatex come in and lecture us. In ASE training programs now, many are teaching not to use gaskets, but instead use gasket maker instead... I got a pamphlet telling me what to use where, and its cool. Next time I drop the pan on one of my cars I am not going to waste my time with a gasket, but instead use gasket maker.

[Ronnie]

I use a product called "The Right Stuff" and it works great. It comes in a pressurized can like Cheese Wiz. Makes it easy to apply. Only drawback is the price. It is expensive.

I used it on my transmission pan and it hasn't leaked a drop since. Before using it on the pan I tried three different gaskets and even bought a new pan and it still seeped.

[Roadster90]

Ronnie,,,,

Chas1 put me on to a TSB (and he has used the TSB info successfully) for leaking tranny pans. TSB is in the long list of TSBs' at Reatta.net. The TSB gives a "part number" for a type of thread locker to use on the pan bolts to eliminate leaking...

[Ronnie]

I tried that Nic. It just didn't work for me.

[Barney Eaton]

If you buy the filter, you automatically get a gasket, so I use them.

I was in Harbor Freight this week and they have a fluid changing machine for only $499

[D-a-n-i-e-l]

Hmmmmm.... You say a "PERMATEX" I wounder why a rep from a major manufacture would say not to use something they do not make?

I do agree with the not using gasket thing a little. The issue I see with it is not evey one has a nice clean garage to work in, the time to wait for the curing process, or the carefulness to not get the gasket maker in places it should not be.

Like Barney said the cork gasket is free, and I have not had any issue with premature leaking of them. (sense I slowed down and learned how to install them correctly)

[Guest Bobby Valines]

I heard that by taking off trans line and starting it, you can get more fluid to come out. Don't know if its true. Every time i have dropped the pan i have only gotten about 4 or 5 qt. to drain. What about fluid in the torque converter and radiator? I was thinking it would be better to do both take off trans line, start and drain with a rubber hose into a container then drop pan and change filter. I don't know woulden't that be the best way?

[D-a-n-i-e-l]

Yes you will get more fluid out, but run a very high risk of burning up the trany pump. If you want to do a flush on your own get some hose a bucket to catch the old fluid and a large container of trany fluid. Place the intake hose into the trany fluid but watch it carefuly. You realy would not want to burn up a pump.

[Guest CL_Reatta]

Or do the "F14 Trans flush" which I did on my cars and worked. It goes as follows (phil of course owns all rights ).

1. Drop the pan and do your filter change

2. Fill up with AFT

3. Take off the trans cooler line

4. Start car and watch the color of the fluid that is coming out of the line, when it comes out clean then turn the car off and replace fluid.

I did this on my capri, I first had just dropped the pan. but a few days later the fluid was burn again. then I decided to do the flush (minus the pan drop) and everything turned out great.

[Guest crazytrain2]

My experience has found several schools of thought regarding transmission fluid "drain" vs. "flush" vs. "power flush" with the latter mentioned type involving running the engine with trans. line disconnected.

Some feel that unless you're having problems a flush or pwr flush is over the top and you run the risk of breaking some gunk loose only to have it end up in a much worse place. (akin to a person w/hardened arteries breaking loose plaque only to have it go somewhere else that ruins your whole day(s))

Others suggest installing in line filtration to catch such items on the way out and before they can go back into sys.

Me? - easy: If it ain't broke don't try to fix it. Change the filter, replace whats lost and be done with it.