AOD Problem NOT TV cable.

[89VertLX]

I bought an 89 5.0 LX convertible this winter with 69K original (documented) miles. The only problem on the car I noticed before buying it was that the ATF looked like it hadn't been changed for a while. So after I purchased the car, I replaced the transmission filter and gasket, and then did a complete transmission flush. I actually had to flush it twice to get the fluid to look and smell clean.

Immediately after this service, I noticed that the car was slipping in first gear. This only happens occationally, and it seems to be more pronounced when the car is cold, although it has happened to me after driving for extended periods. I've checked the fluid, and it is at the proper level and I used the correct ATF in the transmission. I checked the Stangnet forums and previous posts pointed to the TV cable as being the usual culprit. I had a local Ford dealership that I trust adjust the TV cable, replace the rubber grommet, and test drive the car. I also added a BG additive which stopped the slipping for about 400 miles.

At this point, I'm at a loss as to what could be the problem. I don't want to take my car into a transmission shop until I have an idea of what the problem might be.

Any help you all can give me would be much appreciated. The weather is finally getting warm in Colorado, this is my first convertible, and I am itching to put the top down and go driving...

Thanks,

Sam in Denver
89 LX vert 5.0
70K miles. Bone stock

 

[Look Its Aaron]

You got my vote that the trans is slipping and is on its way out.

The fluid could have been burned and by you changing the fluid to a new (thinner and cleaner) fluid, the trans is starting to slip.

You could have done more harm than good?

 

[dvsmike]

ditto

 

[89VertLX]

That's what I was afraid of. I had to literally grind the old pan gasket off with a bench-grinder, so I suspect that the fluid had never been changed before. Anyone else have another possiblity?

Sam In Denver

 

[LX302]

Does it only happen from the 1st to 2nd shift?
Ok, saw that you said is slipped while in first.
If you drive down the road and then hit the gas a little, it will slip until you let off the gas a little , then it will shift into second, right?

If that's the case, I have a solution for you. When you had the fluid changed, I assume you had the filter replaced as well.
There happens to be a small square cork gasket that goes betwween the filter and the valve body. Without this .10 cent piece of cork, your tranny will act this way. It will cause the tranny to not build up enough line pressure, making it seem like it slips. Believe me, my mechanic spent all day on my stang to find the problem after a trans service. Some of the filter kits don't come with this gasket and some mechanics forget to use the old one.

Mine was slipping like this for 2 weeks, and I had no ill effects from it.

Let us know if that what you find out.

 

[legomaniac32]

i agree with lx302...you need that little gasket in there. that could be the problem.
the fluid should have been changed twice in that period you mentioned. that would also explain the old gasket being "burnt" on, when the fluid breaks down it doesnt dissapate heat as well and heats the tranny. changing it would not "cause" slipping in your case. although IF it was slipping before the change, it may make it more noticable. was there a magnet in your pan? and if so was it full of black filings? if there was any chunks id be worried, but if it was all smooth gritty filings, that would be normal wear and collected on there from not having the fluid and filter changed in so long.
your tranny fluid, and filter should be changed around 30,000 miles or so under normal conditions.
it may be a pain, but i would check to see if that little gasket was put on, i believe that may be the problem.

 

[89VertLX]

Thanks for the advice. I'll stop by the parts store tomorrow and see if I can get one of those gaskets. I honestly don't remember if the new filter came w/ one or not -- It's been about 6 weeks since I changed the filter and did the trans flush. There was not a magnet in the pan when I pulled it. The inside of the pan had a lot of varnish on it, but no large chunks of metal anywhere to be seen. Thanks for the info and advice. I'll let you know what happens after put up the new gasket on the filter.

--Sam in Denver

 

[89VertLX]

LX302 and Legomaniac, I owe you my thanks. I got under the car today, dropped the pan and filter and found that the cork gasket for the filter was missing. I put everything back together with new gaskets all-around. I've driven it about 35 miles and the 1-2 shift is good and solid now. This website is amazing...

Sam In Denver