I have a 1999 5.4 L Ext. cab. The sole problem since new has been a bad IAC valve. The truck has seen regular synthetic oil changes BUT no tranny fluid changes in 111K miles. I know, this is unforgivable and I am going to get it changed with a new filter (along with the rear end grease) next week.

I started to experience a peculiar problem that is probably the sign of things to come. After I run the truck for a few miles, the rpm’s (usually over 40-50 mph) will drop 200-400 rpm’s then recover in a second or so. If I goose it, it will recover faster. There seems to be no loss in power, but the problem never lasts very long. This problem happens every trip, but it seems to be more pronounced here lately, starting a few months ago only once or twice a month.

Is this a sign of the tranny needing a fluidfilter change or a more serious problem?

I have recently started to tow my Corvette to the drag races, but have only towed it no more than a few hundred miles (2-3 trips). This problem started before I started to tow the Vette. I have since started using my son’s Power Stroke, since it does not know there is a trailer and car back there!

 

Get that tranny fluid/filter changed. If you have towed alot with this truck it should have been changed every 30,000. Have you noticed the problem with or without overdrive. Sounds like it's dropping down then back up to compensate. If towing the vet may want to run with overdrive off. Good luck.

 

I have only towed the 'Vette 4 times, but 3 of the trips were 140 miles round trip (to Ennis Texas Motorplex) and these were obviously at freeway speeds and a bunch of downshifts going up and down slight hills. I have not really had the time to experiment taking the overdrive off during this problem. Interestingly enough, I just got back from a short (10 mile trip) this morning and it did not show the problem. But it did yesterday a few times.

I am going to get the fluid changed tomorrow or today if the shops are open on New Years Day. BTW, most of these shops only flush the fluid and do not change the filter. Do you think that is OK or should I find a shop that changes the filter also? I remember asking the Ford dealer a year ago what they did and they do not change the filter also.

Thanks for the reply!

Roger

 

I would definitely find a place that will also change the filter. Simply flushing the transmission will not get all of the crud out of the transmission. Most transmissions actually have a magnet inside the pan that needs to be cleaned.

Especially since the fluid has never been changed, I would definitely find a shop that will drop the pan and change the filter.

 

Have you done a tune up on it?
How are the plugs etc?
Ever clean the MAF? If it's dirty you can get a "surge".

 

May want to change the fluid and filter in the pan yourself for a couple of reasons. Save you money on labor at shop. You will be able to see how much dirt,grime, from all those miles. Just did it on a 2000 F150 with over 100k miles i bought. Didn't know what kind of maintance was kept on truck if any. Truck had a shimmy in it when shifted into overdrive. Hasn't done it sense. Plan on haveing it flushed after a few thousand miles.

 

Thanks for all the replies. I had changed the plugs some time ago (85K miles). They looked to need to be
replaced and the truck did run better (easier to start and better gas mileage).

The fluid is being changed tomorrow with a new filter. I would change it myself as I have all the tools, lift, etc. but I have changed tranny fluid once before years ago and never again. It is easy but very messy and a lots of it!

Hopefully she will be back to normal in a day. Still the best running 111K vehicle I have ever owned (since 1967). I usually put 120 to 150K miles on most of the cars I have had lately (except the Vette. It goes a 1/4 mile at a time! )

 

rwhite........A ford dealer should drop the pan and change the filter. They can power flush the tranny. Athens, Tx Ford Lincoln Mercury did that to my 99 sable with 150,000 about two months ago. It has been changed religiously but still there is a slight surge or downshift sometimes below 30 mph. It makes the commute to Dallas and back everyday.

Personally, I think the Vette, trailer and goodies you pull is too heavy for the truck. I would say the same thing for a Chevy or Dodge or any other make.

Manufacturers are not always upfront and honest about what work their trucks can do. I have been around trucks as long as I can remember. Going back to 1963-1964, and I am not that old...45. Yes, from five years old and on.....Friends of ours had a trucking company. You name it, he had it. REO's, Hendrickson's, Dodge, Chevrolet's, Ford's, Mack's, KW's, Peterbuilts, IH, White, etc. They were either dump trucks, cement batch beds or tractor trailer combo's with flatbed trailers.

He always said, buy something bigger than you will need. I guess you can feel the difference with your son's PS. That is exactly what you should always feel when towing something. Nothing......... You know what I mean. Braking while towing should be the same thing. The truck should not labor to stop itself and the load. I guess it's great for everyone, they build these fancy, powerful diesel's yet the MFG's. don't give it a second thought when someone has to make a panic or fast stop with a trailer loaded down with goodies on it.

I am not far from you and to see some of these guys drive what they think is a fancy truck, yet they cannot see what's behind them in their mirrors because......basically, the truck is too small and narrow and the load is too wide for the load it's carrying. Trailers loaded with rolls of hay is a prime example.

I truly have not found a ford dealer in the Dallas area that I can trust and view the work. I know all about their lame insurance excuses, but then again, I want the dealer to solve my problem not just try to explain it away and charge me.

Westway, Skyline, Leadership all let me down and they were told so. They sure do want you to buy a car, but when it comes to service they all FAIL, regardless if it's warranty work or wear and tear! Although I never bought a car from either dealership.

I have had excellent service with Athens Ford Lincoln Mercury and Quitman Ford in Quitman, Tx. I can stand by the serviceman when he is working underneath my 01 F150 or 99 Sable and ask questions. I know enough of the old school mechanics where they cannot pull one over on me. Hey, the new computer/sensor garbage is just that.

Let me know if they find anything major when servicing the tranny, my sable may be headed that way.

Enough preaching. Good luck with the towing and the vette.

 

It was North Central Ford (Richardson) that said they only flush the tranny. I too have not found any reliable dealers that have good shops that I would trust. That is why my son and I do most of our on work except for the warranty stuff Ford owes us. And as you know, they will not tell you many times that is has a problem that needs to be corrected.

I was one of the first ones in the country that had my T45 on my '97 Cobra grind when you did an aggressive cold tranny 1-2 shift (found at 400 miles one month after I bought it when the ‘97’s came out). The dealer changed the tranny first with no questions asked, but then one year later, after the problem was wide spread and well known by Ford, they would not change the tranny when it was grinding again. Eventually they went to a better tranny (the '98 I think was beefed up a little, a new manufacturer took over the tranny. Tremec).

I agree the F150 5.4L is barely able to pull the load I have. My older son fortunately lets me borrow his truck here lately when we race (usually at Hallsville near Longview). I told my son that I wanted to change my tranny in the ‘Vette first before the truck one goes kapow! I am nearing 500 crank HP in the ‘Vette and the stock tranny is starting to show that it does not like that!. After I put in some roll bars, I am going to order a beefed up tranny from FLP that will handle up to 700 HP.

Again, thanks for all the replies. This forum has been real helpful and I have bookmaked it along with all the Vette and Ford forums!

 

I have a 1999 5.4 L Ext. cab also. However mine is the light duty 250 upgrade. Last March I pulled a 26 foot fifth wheel (about 7,500 lbs loaded) from Michigan to San Diego and back for a total of 8,000 miles with detours. Even though I was cranking 5,000rpm up some of the mountains, I never had any problems.
What is the mechanical difference between these two trucks?? They look the same. Is it mechanical or just suspension differences??
I did however have the tranny flushed at 46,000 miles when I returned.

 

hey ray hamel, my names ray too, i also a 97 f2504x4 they call a light duty, it looks like a f150, i tow a 18ft cronkite with 5000lbs of Allmand backhoe on it, does great, but like you asked, just what are the differances?