Hey gang. So I need a little help. Here's the deal

I have an 07 f150 screw. 4.6 auto 2wd. I bought it used, it just had a used transmission put in it before I bought it at the dealer. Not a Ford dealer!
so it feels a big sluggish off the line. It's a 4.6, I just got it, I figured yeah it's a little gutless so ok. But driving, it has much better power.
Here's where it really stands out. Towing. I had a uhaul car trailer with a Dodge Dakota on it, and I think if you stopped on the right hill I'd be in trouble. It takes off so poorly that even with less than it's max tow capacity, it is a real dog. You'd think it's taking off in 2nd gear. But it's starting in 1st. I'm getting all my years, certain of that.
Just wondering if the truck should have been reprogrammed with replacement trans? Or is a 4.6 really that dead from a stop?? If it is I might change rear ratio to 4.10 as I will be doing a lot more towing now. I don't care if I lose a few mpg on the highway, I need this mule to get the job done. Or I'll just have to find a different tow rig. But I own this one and really like it.
Any suggestions? I will add this. This truck cannot, in any way, empty on rain spin the rear tires. It has limited slip, but even on wet road it can't do it.
But on highway it seems like it has solid power in od at 75-80 it just pulls.
I'm confused. But I also don't understand much about the electronic side of these things with programming and what not.


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One other thing to mention. This truck has 312,000 miles on it. It runs great, quiet and smooth. But I have wondered if converters could be getting plugged? I'm thinking engine may not be original but haven't looked into it. It runs good aside from the takeoff power.

 

You should get Forscan (a free download at www.forscan.org) and an ELM327 adapter (around $30) and use them to look at data from the PCM. That will tell you what the gear ratios are when you launch.

It also could be a bad torque converter. If the converter has a failure it won't multiply engine torque, and it will be a dog off the line. Of course, it could be an engine issue. There isn't enough data without Forscan to be able to tell what is causing the problem.

 

Thanks, I have the adapter. I've used it with torquepro app on a 6.0 diesel. I'll check out that forescan deal. I appreciate the help. So that app will show gear ratio while it's driving? That's pretty cool 👍

 

Cat converters don’t spontaneously melt down. If the engine was swapped and cats not changed, that’s a problem.

As for that Dakota and a trailer, that SCrew tows a max of 5900 lbs with the 18” wheels and 6400 with the 17” wheel option. You’re right on the edge or beyond what a 4.6 is comfy towing. Since a 4.6 has a peak torque output around 3500 rpms, you really need to make use of the gas pedal and OD Off button to help your cause.

As for the limited slip, they use a friction modifier in them. I bet that wasn’t ever changed.

I’d find a different tow rig. I remember my brother wanting me to tow his new Wrangler from Dallas back to Houston. Would have been overloaded per Ford’s specs and probably in single digit MPGs. At that point, I was fixing to borrow my stepdad’s 7.4 2500 Chevy.

 

I don't think the converters melted. I'm just asking about them being clogged?? Or potentially. This ride has 312,000 miles on it. I have only put a few thousand on it myself. Prior to me, it had 3 coil packs replaced and all 8 plugs. I was told it had a missed misfire.
and it had a used transmission put in it as well.
The dealer got it at an auction and repaired it.

So, onto towing. It has 17" tires. 3.55 rear.
No issues going down the road. Handling is good, brakes seem adequate. It is only off the line that it's really weak. Empty or loaded, but certainly obvious with some weight.
my 95 with a tired 5.0 dog automatic will eat this thing alive on takeoff.
I doubt that other f150's with a 4.6 drive like this. It pretty much feels like the truck takes off in too high a gear. But it is in 1st. With nothing in it and no trailer it feels like this so we can take the towing right out of the equation. It's just worse with weight
It seems pretty normal except takeoff. Power on highway is decent. It's not a ball of fire locally but it doesn't seem overly weak. I figured the 4.6 in a crew wouldn't be killer powerful but it's alright

 

I probably will have to get a tougher tow rig but I'm just using it locally for now. But in the meantime, I do need it to work!

 

The way that converters clog is that they melt internally.

 

Well, I can't say if the converters have clogged/melted or not. Is there a pressure test or something that could be done to diagnose such a thing? With old carbed rigs i had, I always felt like cats where the enemy. lol ever any question, ram them out. But, this is a little newer and costly to just start hacking at. This truck had misfire issues prior to my buying it. The dealer replaced all 8 plugs and 3 coil packs. I'm thinking a misfire could damage a converter if driven enough? I have no knowledge of the history of it. But it had misfires and a bad transmission, which leads me to believe the misfires where happening for a while prior to transmission failure and auction of truck. I have no misfires or fault codes, engine seems to be running fine, aside from being weak on takeoff.
As for transmission and torque converter, I already had torque pro app on my phone so I loaded features I want to look at and a couple times I had some driving to do I ran the app watching rpm, torque, torque converter rpm, and a few other things. As far as torque converter lockup, it seems to be working just fine. It will show zero torque converter rpm when it is locked, and a range of rpms when it isn't. Highest rpms when you are sitting and just starting to move. So I think it is safe to say the transmission/converter question is ruled out. You can also watch what gear the transmission is in, it seems to be functioning just fine. Takes off in 1st gear as it should, torque converter not locked based on the torque conv rpm on takeoff. I think it is just geared a little fast for towing anything more than a boat. lol
I have come to the conclusion that for towing, I simply need to upgrade to a bigger truck for my car hauling trailer. This was never intended to do this work, it was to be my daily driver and maybe randomly tow something, but a month after I bought it I got laid off temporarily, and then it became permanent. That's where the towing fell into play. I need to do some hauling to make a buck.
In the meantime, I just need to use it until I find something with a bit more capability. And have it in tip top shape to sell as I won't need it anymore.

 

On the converter melting, I wanted to say thanks. I have seen a melted converter before, but never one someone called clogged. I had it in my mind that clogged was just that, maybe plugged up with soot type stuff preventing airflow. Never really considered a melt as plugged/clogged as I just hadn't had it explained to me that way. I am far more int other diesel world with my training and experience. In the late 80's when I was thinking about tech school after high school, I avoided auto tech and went right into heavy duty diesel career to avoid the efi, vacuum and egr junk, etc. Of course early 80's cars were riddled with vacuum hoses and issues from leaks thanks to the loads of connections and so on. I very much enjoyed heavy duty diesels, and 18 wheelers. Nothing better than hearing a diesel you rebuilt pulling at its best. But then, time caught up with diesels too. Took a good thing and screwed it all up and over complicated a very simple dependable thing! Anyhow, converters weren't put on diesels until I was just about out of that career so I don't have much experience there, and the diesels are really more particulate filters that do actually clog if not taken care of correctly. But now, I do know the difference with the gas engine converters!

 

Are you looking at actual calculated gear ratio, or at what gear the PCM has told the transmission to be in? There can be a HUGE difference in those two. The gear ratio could be second gear when the PCM wants first gear. If you don't look at the actual calculated gear ratio you won't know this is happening, except it will be slow off the line.

 

I think it is showing me what gear the transmission is in per pcm. It seems right if you go by how it shifts. If it really was trying to take off in 2nd gear I don't think it could do it with a load on. I just don't think it would be able to move. I'd like to just toss the automatic and pop a 5 speed or 6 speed manual in its place. And maybe drop the rear end ration to 4:10. But I don't think I will. I will most likely just buy a F-250 or F-350 and sell this. Its fine for normal driving, just not great for much of a load. For occasional towing it isn't terrible, my issue is that I am needing for towing more and more. When I bought it, I didn't have the need for towing. But now I do. New truck it is I guess.

 

Let's try this another way. Are you looking at numbers like 1, 2, 3, etc? Or ratios like 2.71, 1.54, etc? The first one is the gear the PCM is commanding the transmission to be in. The second is the PCM measuring the actual gear ratio of the transmission in real time.

I know for a fact that yes, it can move starting in second gear with the truck fully loaded AND a trailer attached. I've tested it.

 

I am seeing the gear, "1" not the ratio. And in each gear I am seeing the torque converter rpm. At lockout it is zero. Sitting still and taking off i torque converter rpm went up to as much as 1600 rpm maybe? But I am not seeing actual gear ratio. I will look at the torque pro app and see if I can get it to monitor that. If not, I did load the forescan app, just haven't tried it yet. But I might be able to see it with that.

On the 2nd gear start, that must have been a really tough pull to get moving!

 

I'm not seeing a way to add actual gear ratio to torque pro app. It may be able to be pulled and manually loaded, I had to do some of that for a 6.0 powerstroke I was working on. I will hook my truck up with the forescan app and see what that looks like.