4r100 Starting in 3rd gear

powerstroker66 · Nov 16, 2017

My 1999 4x4 f550 i recently purchased has not run for about 3 years. I recently got it running and driving but the transmission seems to be wanting to leave in 3rd gear. I can manually put it in D2 and D1 and get it to leave in 2nd gear but thats it. Im getting no codes, all output sensors are reading normal, and according to my Modis, Its calling/saying 1st gear. Goes into all gears no problem including over drive. Reverse works so i don't think the clutches or anything are bad, my guess would be there is a solenoid hanging up from sitting? Any input greatly appreciated, Thank you!!

Mark Kovalsky · Nov 16, 2017

You've described exactly what happens when the shift solenoids are not powered. Check for +12v at the connector on the passenger side of the transmission.

powerstroker66 · Nov 17, 2017

If the shift solenoids are not powered doesn't the transmission stay in 4th not 3rd? PCM powers 12v to the solenoid pack correct? there is no fuse if i recall....

Mark Kovalsky · Nov 18, 2017

Yes, it stays in fourth gear with no power, not third. I think you were guessing it was in third gear.

powerstroker66 · Nov 19, 2017

The converter does lock in 4th and it does go into over drive...

Mark Kovalsky · Nov 20, 2017

Fourth gear IS overdrive. There are only four ratios, and fourth gear is 0.71:1, which is overdrive.

Do you have a way to look at live data? Can you watch what the PCM says for what gear it's in and compare that to actual shifts?

powerstroker66 · Nov 25, 2017

yes, you can see it commanding different shift/coast clutchs and what the neutral saftey is reading. I had a local trans shop scan it since their scanner is more updated then mine and it threw 2 trans codes...1st gear solenoid wiring fault (i forget the code #) and incorrect 2nd gear output ratio range. I'm going to pull the pan and do a new solenoid pack, fresh fluid and filter and see what it does. From sitting under a gravel floor over hang for 3 years i think something is hanging up from condensation etc.

powerstroker66 · Dec 2, 2017

Alright, new OEM solenoid pack, fresh fluid and filter, same issue. I'm thinking PCM/harness?

Mark Kovalsky · Dec 2, 2017

It's most likely the harness. Time to diagnose the wiring.

powerstroker66 · Dec 3, 2017

I have a known good harness i think im going to swap in and see what it does. I also have a pcm from another 99' auto 550 i can swap in too to weight out what it might be. Local trans shop claims if it was something internal in the trans you would know..also pan/fluid was clean as a whistle..

DanJack · Dec 18, 2019

Have you solved your issue?

Hey powerstroker66, I have a 1999 F250 with the exact same problem. I installed a new solenoid pack and ECM and problem persists. Did you ever solve the problem you were having? If so how did you fix it. I appreciate the help.

mandkole · Dec 18, 2019

Pretty sure he sold that truck awhile ago.

Mark Kovalsky · Dec 19, 2019

DanJack said:
Hey powerstroker66, I have a 1999 F250 with the exact same problem. I installed a new solenoid pack and ECM and problem persists. Did you ever solve the problem you were having? If so how did you fix it. I appreciate the help.

What codes are stored in the computer?

Is there power to the transmission connector? The one on the passenger's side of the transmission.

DanJack · Dec 21, 2019

Weird codes

I used a simple code reader and no codes showed up. I then used a more advanced reader and it showed a problem with one of the pistons. The motor however runs great no misfires and idles smooth. The check engine light is not on. The mechanic who had the second reader told me that he believes it doesn’t have enough power to the ECM but couldn’t find anything wrong with it.

Mark Kovalsky · Dec 22, 2019

A piston problem? What code was that?

If the mechanic has a voltmeter he can tell if there is enough power to the PCM (Ford calls it a PCM, not an ECM.) If he doesn't have a voltmeter he isn't a mechanic.

pcweber · Oct 24, 2021

Was there ever a resolution to this symptom? I have the exact same situation. I have afformed I have 12V power to the trans connector. I also have replaced the TSS & OSS, and the solenoid pack in the trans and the same starting in high gear persists but can manually put the shifter in 2 or L and it will start out in those gears. Can the gear shift selector switch that mounts over the top of the gear selector input cause this?

Mark Kovalsky · Oct 24, 2021

No, it cannot.

You have a wiring harness problem. It could also be in the ground side of the harness, not just the power side.

pcweber · Oct 24, 2021

Thanks for the reply. Is the harness section going down to the trans a section that can be replaced? I have access to an Excursion I can get it from if so.