I have a 1999 F150 with a 5.4L V8. It has 236,000 miles. The truck has been sitting unused for several months. The transmission was fine when I parked it but, recently I got it out and started to drive it again.

Now, I'm having some problems with the automatic transmission. It accelerates fine through first and second gears. Shifts smoothly from first to second. However It doesn't seem to want to shift into third then it begins to rev and slip.

I have checked the fluid level and It's fine. I did detect a "slight" burnt smell to the fluid on the dipstick. It hasn't been driven very far at all since it first began to slip.

I think I'm going to pick up a filter and change that first. Any other advice?


By the way: I have never serviced the transmission. I talked to a mechanic back when I bought the truck (with 118,000 on it) and he told me that, since I didn't know if the transmission had been regularly serviced, then It would probably be best not to do anything to the transmission. I thought at the time that this seemed like crazy advice. That's why I asked a second mechanic and he seemed to agree. So I didn't do anything. And that was almost 120,00 miles ago.

Thanks,

Mitch

 

I get tired of stupid mechanics giving ****ty advice like that. I would change the fluid and the filter, but DO NOT do a flush, that is what will mess your high mileage tranny up. Somewhere, somehow, some jackass mechanic got the wrong impression that changing the fluid and filter in a high mileage vehicle is bad and that bogus myth has spread like wildfire. That is the dumbest crap I've ever heard, I guess the oil doesn't need to be changed either then, lol.

Be careful when letting mechanics tell you stuff like this, especially of they're a dealership mech. Change the fluid and filter and you should be fine. I won't promise it'll fix the issue you're having, but it's the cheap start to finding the issue.

 

I'd start with fluid and filter and if that doesn't help start saving up for a tranny rebuild, 236k miles isn't a bad run

 

Fordman is right, don't do a full flush, just drop the tranny pan, switch out the filter and full up. Replace one quart of ATF with the Lucas transmission additive. I did this last March. I was getting a little slipping and harder than normal shifting. The Lucas smoothed it out. My 99 5.4 has 393,000 miles on it and I was told it was rebuilt around 200,000 miles. Just be aware of the amount of metal shaving in the bottom of the pan. If there is a mountain in the pan, you got problems.

 

I've got 172k miles on a 97 with a 4.6 4x4. Would you give the same advice? Filter and fluid minus a quart for Lucas.

 

Sorry, didn't say it but I've got no clue about previous flushes or filter replacements. Bought it with 160k miles.

 

Well I dropped the pan and there didn't appear to be any metal shavings in there. I'm on my way to the store to pick up a filter, some replacement fluid, and a quart of the Lucas. I had to come in and shower first. Somehow I got transmission fluid in my hair.

I'll let you know how it goes. Thanks for the advice.

Btw: The original plug from the factory was still in the pan. I assume the Transmission has never been serviced. Or else whomever serviced it left the plug in there. 236k without a fluid change. Wonder how long it would've lasted if I'd taken proper car of the thing??? live and learn.

Thanks,

Mitch

 

Yep, drain fluid and replace filter, absolutely no flush.

 

did you find the yellow bobber thing in there?

 

Is this rocket science if I have never done it before? What are the exact steps so i dont screw anything up. Assuming I just remove the pan, empty, replace filter then pan and then fill up from the dipstick?

How many quarts? Do you guys have a preferred brand or the usual Motorcraft?