after reading about torque convertor shudder, I took my '99 F150 to the dealer for a transmission service. imagine my surprise when I found out they no long replace the filter - they just back flush the old fluid out. (it's been a long time since I've had an automatic transission) truck has 108k miles, and the service manager says not to do anything, too many miles on it. he says new fluid will build up more pressure likely causing seals to blow.

any thoughts from the experts?

 

Just drop the pan, put a new filter in and refill with fluid.

 

Do not return there. People who believe old wives (old mechanics?) tales about hydraulic systems (which is essentially what automatic transmissions are) don't need to be working on your stuff.

 

being an old gearhead, I called BS on what he said, and won't take the truck back there.

I wish I could just do it myself, but, my worn-out body won't allow me to do those kinds of things anymore. my second choice will be an independent shop.

 

Take it to an independant shop. If they aren't gonna do something that ez they should be reported. I went as far as to put a remote cannister type filter in along with a better oil cooler. Oh there's a temp guage also.

 

i know exactly what the dealer is talking about. Customer brings in truck with trany problems for service. Shop services trany, and trant goes out in a few months. Customer blames shop. I have seen higher milage tranys(with no service) come in the get serviced, and go out shortly there after. Having said that I don't beleive the service caused it, but the lack of mainance leading to that point. Most people just forget all there lubed parts until it starts acting up. Then the first thing that do is change the fluid, but the damage is already done.

 

108k isn't that many miles. While I have seen problems caused by new fluid, it's generally on a transmission that is already wrecked, and someone is just changing the fluid to see if it fixes it. Mainly with a slipping band/clutch problem or internal mechanical damage.

I think dealers will tell these stories 1. because they are partially true and 2. because they want to scare you into buying a new car.

 

I am very familiar with this issue, not that I personally work on transmissions, but I work fairly closely with a transmission shop that is very knowledgeable.

The issue is a combination of things. Firstly, the flush machine when used without dropping the pan and changing the filter first, will stir all that crud up and it will go where it is not supposed to go. Secondly, the machine forces fluid to flow backwards through passages that were never designed to have backwards flow at pressures they were never designed to handle in either direction. This causes damage to the seals in the valve body, which can cause major problems.

The proper thing to do is to get all the old fluid out using the transmissions own power. First off, drop the pan and replace the filter, and check to see what kind of material is on the pan before cleaning it. Refill to the proper level. This replaces about 1/3 of the fluid. To get the rest you need to exchange the rest of the old fluid for new. This may require s a friends help. Disconnect the fluid return line and run it into a 5 gallon bucket. turn the ignition on and pump out about a quart, then add a quart through the fill tube. Repeat this process until old fluid stops pumping out. This can take up a lot of fluid, but it works and it is safe. When you are all done, check the fluid, make sure it is at the proper level, then drive it around for a few minutes, and recheck the fluid level, add or remove as needed.

If you drop the pan and replace the filter on 30,000 mile intervals, there is no need to exchange all the fluid. The exchange method I mentioned is only needed on transmissions that have been neglected for longer periods.

 

you are absolutely right about servicing any vehicle on a routine basis. I have no idea what was done before I got it, I just want to do those things to it to make it last me another 10 or 15 years.

thanks to everyone for responding.

 

A 99 year truck should have a torque converter drain. If you drop the pan, replace the filter and drain the converter, you will be replacing nearly all the fluid.

 

Is there a time interval like 30,000 miles or 3 years? It will take 5+ years for me to drive my pickup 30,000 miles. Just go by the miles?

 

the service department loses out when a customer buys a new car so I doubt that is true

 

We didn't flush hydraulic fluid on jet fighters (F-4, F-16 A/B/C/D) unless it was suspected contaminated.

There is no reason to flush any hydraulic system that has clean fluid. Drain, swap filters, replace fluid, end of story. The solution to pollution is dilution.

 

Go by the miles.

 

For -what-its -worth
I too had similar experience....wanted to change the tranny fluid and filter.
Inquired at the local Ford dealership...they explained that they would flush only...no filter change. whaaat?? no filter

I thought what is the point, without the new filter??

went to a smaller shop inquired there...he explained that sometimes with new filter and fluid it will flush contaminates into the valve body and other areas that they're not suppose to be and one will have more issues then after wards....naturally most point finger back at the where the tranny service was done. It is hard to say how it will turn out. Most-likely the tranny was gasping last breaths prior to service anyway.

I had him (smaller shop), change the filter 1st, retop off with generic tanny fluid, then do the flush with tranny fluid & filter I supplied (M1 syn) & I've had no issues to date. I did not install a line filter...maybe I should of??IDK This tranny service was done last summer I figured it would show its ugly head by now and I've pulled a 14' trailer with 3 ' sides laden with fire wood a couple of times earlier this winter. It managed it fine, no issues.

yes, it cost me a bit more...but it worked...& there was approx 137k on it & yes he found the yellow plug in the tranny pan...so it hadn't been serviced prior, or at least the filter hadn't been changed...from what he said the fluid wasn't very nice looking either, so it was prolly all original.