Hello everyone ime new to a Forum, ive always been a 8 out of 10 self mechanic, Ime stuck however on my 2002 ford 7.3 POWER STROKE , this is the first Ford Diesel i ever own, i have a lml duramax 2012 that i deleted so i believe i have some knoledge on mechanics, anyways i need help, ime willing to compensate anyone that can help me fix my issue. I baught a 02 Ford F550 with about 367k miles, truck engine is empicable, no issues at all or check engine lights, when i got truck the od light was flashing and hauling a 16k pound trailer truck would go down to like 2nd gear, also i had no lockup in torque converter, anything over 55 mph i was pushing close to 2200+ rpm,s. i ended up having tranny rebiult and new torque converter, however truck still does not lockup torque converter, all the transsmission codes are gone and truck transmission shifts fine, except i cant drive over 60 mph, my rpms even at 55mph are still 2k, i changed the brake switch under dash by brake pedal, i dont know what else to do, i believe i have an electrical issue, the guy who rebuilt my tranny said he changed all the solenoid packs, i would love to know how to manually try to lockup converter , or where the converter lockup solenoid iss in a 4r100. the od button works fine and shifts smooth, my only issue is no lockup in converter, does anybody have an idea how i can diagnose this, maybe looking for tcm? or Ecm and checking wiriing? please lend me a hand, i promise i will compensate anybody who can guide me and i get it fixed, ille venmo, zelle, paypal u some Beer (corona) money lol. thankyou.

 

It's late in the night, most the gurus on the auto transmissions are asleep, I'm working nightshift so here I am. Since I have a manual I don't usually read up on the auto's threads enough to know where to splice in to manually lockup the converter.

Just letting you know you came to the right place, your thread isn't being ignored. This is like one big family here, so you'd have to force any compensation into someone's pocket, the info will come rolling in for free

 

thanks Bro, I appreciate the Hospitality, and if i can get my truck fixed, well even better.Ime Excited to be part of this Orginazation. appreciate it again!!

 

Here's the TC manual lock write up. It's in the tech section for future reference. Not listed in the 4r100 subsection but at the very bottom after all the other sections is a list of private 7.3 websites. This gem is from Guzzle's page. Lots of good info in our tech section on pretty much every system on these trucks. Anyway here's the link.

Welcome to guzzle's TC Lockup Mod Web Page

 

thanks bro, i will look at it tomorow, i will update if i find anything!! ime going to take harness apart, thanks again

 

Its a f550, that means 4.88 gears. 2200 rpm at 60mph is normal for that. You can go faster, running all day at higher rpms hurts nothing, just noisier.


A 7.3 feeling turdish hauling 16k is also normal when you are used to towing with a lml duramax

 

Welcome to the FTE!

I have a ZF6 manual and generally believe an automatic transmission is a box of magic that does what it wants when it wants. If you want to verify the TC is locking up, you can do that with a scan tool and a mobile device for a small fee or a Windows laptop for an even smaller fee.

Start here and with the last link which is the Q&A... All of this information was copied from the 7.3L PSD Tech Folder on the main sub-forum page.

FORScan

• FORScan Instructions - PC
• FORScan Lite Instructions - Android
• FORScan Lite Instructions - iOS
• FORScan Data Log Conversion
• PERDELs via Forscan
• Cruise Control/Speed Control Forscan function test
• Speedometer Calibration Using Forscan - Thread
• Speedometer Calibration Using Forscan - Video
• FORScan + FORScan Lite: Class Tutorial Q&A

 

If the torque converter isn't locking there WILL be codes stored. What codes are stored?

 

This.

What makes you believe it’s not going into TC Lockup? Just the rpm? Or are you monitoring something?
Your rpm sounds about right for that gearing. Towing heavy you will likely want to be up higher than that anyhow.

 

Hey bro i thought about that same concept, however u can tell once the overdrive kicks on, nothing else seems to relieve the rpms, normall the tc lockup relieves the rpms a little, in my case nothing, ive seen videos of peoples tcc kicking on and off and mine does not kick on at all, also my fuel milage is terrible, i have a buddy with a 450 and he is at 1700rpm going 60-65, if i try hitting 70 mph, my rpms go all the way to redd, at 2500!! Then when i let off fuel, i can feel the engine start coming down like an exhuast brake since its rpms are so high.. i know forsure the converter is not locking. I do believe i might have low gears but shouldent be so badd. I feel like ima throw a rod out the side of the engine block.

 

no way the 450 has stock gearing (4.30) and runs 65 at 1700rpms, unless he had big tires, which is rare on a dually cab and chassis

I bet your tc is locking as soon as the shift to 4th.

2500 rpm is nothing, redline isnt until 3400

the fact it feels like an exhaust brake when letting off throttle further points to the tc being locked

 

 

That is how it behaves when the converter is locked up. If it was unlocked the RPM would drop to 900 and your speed would remain the same.

Converter lockup only changes about 200 rpm. Mine happens at 40 mph, usually before OD. Lockup speed depends on the ECU, different variations lockup at different times in different situations.

I'm at 2100 rpm at 65 in OD, and I have 3.73 gears. About 2600 RPM in 3rd at 65.

 

So ur right budd, ime amazed at how high of a RPM these 7.3’s run, ive only been owning this truck for about 6 months, wasnt driving it much since i thought Tranny had issues, i ended up grounding the pin 6 while on Drive and it popped the converter like i was popping the clutch on my 454 ss 😂😂 anyways i guess its normal for these 7.3 with 4.88 gears to runn this high of an RPM as u mentioned, i ended up running a switch to pin 6 and grounded it, can i use this to lock converter when in need? Or will it cause damage? Oviously i know not to lock it in 1st gear , also made the od light flash but i read that was okay . My other question is what would be the max rpm i can cruise too without beating up the engine? I might end up putting bigger tires to try and bring rpms down a bit. Anyways thank you for ur advice..

 

In boats they run them at 3k all day long.

I like to stay around 2k because it's quieter, but when I'm towing I'm usually at 2500. It makes more power (and burns more fuel) above 2000 anyways.

I dont like shifting the TC on a switch because it's on or off. The ECU uses PWM to make it a bit more gentle, I'm sure you now know what I mean.

If you switch it while it's floating between drive and coast it's less jarring.