2010 Ram 2500 6.7 118k mi. after 50 mi trip stopped.transmission stays in 4th with check engine light on. All other Gages normal .3 mi to home. Tried restart mode but still the same.

The Check Engine Light is on? Did you read the DTCs.

The second link has the answer, the first link says it is a known issue. It is times like this you need the Dealership or a good auto electrician.

Transmission won't shift to third until temp rise

ClubLexus https://www.clublexus.com > forums > 713188-transm...
Apr 1, 2017 - Transmission won't shift to third until temp rise ... The solution is to drive slow and keep rpms at 2.5k and 3k at max till the engine and transmission warm up.
Sometimes transmission wont shift from 3rd to 4th - ClubLexus
Aug 23, 2021
Won't shift from 3rd to 4th gear - Lexus Forum Discussion
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RX300 not shifting into overdrive. - Lexus Forum Discussion
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FIRST POST! RX300 no 4th gear a full year. Fixes? - ClubLexus
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More results from www.clublexus.com

Owner of Lexus RX300 with 182000 miles. Recently the ...

JustAnswer https://www.justanswer.com > lexus > 3wsxt-lexus-rx3...
Aug 22, 2010 - Recently the transmission won't go into overdrive. Stays in 3rd gear like when you press the o/d button to do so. When car is cold (live in ...
1 answer · Top answer: Hello and thank you for using just answer! The check engine light is on correct?

https://www.google.com/search?q=Lexus+RX300+will+shift+into+overdrive+once%2C+and+after+slowing+down+it+won%27t+go+past+3rd+gear

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Corrupt adaptive shift memory. Try clear and relearn.

https://youtu.be/jWMliD_3s3o

Are you sure it's 4th? could be 2nd. Stuck in limp mode. Engine light on? Have the codes read.

I would go ahead and get the engine computer checked for trouble codes just to be sure. Most auto parts stores will check for free.

look for trouble code pcm, for transmission problem it's normal when there is a code affecting trans . in default mode pcm command high pressure not to burn it . could command no tcc or 4th gear
hope it helps

chances are the bottom hose has "blown"its NOT advisable to drive it ANY distance but get a local mech to fix it asap.fill it up before you drive and if red light appears STOP and refil with water (blue light only comes on when COLD).

2000 Honda Passport v6 auto transmission..at time transmission did not down shift when stoping and it would stay on low grear. when going after stop it would be on low grear but pick up speed to go 45 mi. pmh but would not down shift when stoped. until maybe 3 miles and it would down shift at stop or when driving at slow speed?

Hi:
The first thing to do is to have someone check to see what code is tripping the check engine light. Most auto parts stores will do this for free. Check to make sure your transmission fluid is full, and clean. Sometimes a vehicle speed sensor can cause erratic transmission up shifting, but see what codes are tripped first

CHECK GAGES light (1) indicates a potential engine failure(low oil pressure, low coolant, coolant overheating) has occurred.
· Check gages and shut down engine. Gages should read as follows: Oil pressure 5 to 10 psi (34 to 69 kPa) at idle; Water Temp gage below 230 degrees (110 C).
· Check engine oil level (Para 2-11) if OIL PRESS gage indicates low reading. Check coolant level (Para 2-11) if Water Temp gage indicates high reading. Notify Unit Maintenance if levels are low.

If CHECK ENGINE light (2) is on, check engine oil pressure gage (3) and water temperature gage (4). If both indicate normal, proceed with mission and then notify Unit Maintenance. If either one does not indicate normal, stop engine immediately and notify Unit Maintenance

TCU (Transmission Control Unit) Located behind the Passenger Kick panel. it will have a burnt diode inside and can be purchased on ebay for about 79.00 with exchange.

Lugnut61