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Transmission Trouble: Automatic Not Shifting to 5th Gear

I don’t do alot of high speed driving. I noticed today when I got the car up to 65 mph that the engine was laboring and the RPMs were 500 to 1,000 higher than they should be. I thought that the transmission was not shifting to 5th gear. I got off the freeway and traveled smaller roads not going above 50-55 mph. Under these conditions the transmission seemed to shift normally.

Is the car save to drive at speed under 50 mph without repairing the situation?

What is the possible range of cost to have the transmission repaired for this defect?



Year and engine size on your lebaron… What kind of miles are on it?? When was it last serviced and what does the fluid level and condition look like??


Thanks for the interest…
The engine is a 6 cylnder. The transmission has been regularly maintained in terms of flushing and replacing fluid. Previous mechanics have commented that the car is in ‘great’ shape fundementally. The car has 102,000 miles on it (7k per year).

Are you sure the car has a 5th gear??

I don’t know for sure if it is a 5th or a 4th gear that is involved. I assumed it was a 5th gear given my previous expereince driving a manual transmission.
I do know for certain that the car is not behaving like it previously did at speeds over 50-55 mph. The laboring sounds and higher RPMs are unmistakeable.
I hope that this helpd and thanks.

Its not a 5 speed. Its a 4 speed A-604 transmission. That much of an increase in rpm’s sounds like there is a problem in overdrive. Its time for a trans shop to scan the TCM for codes, CVI values, and to see whether the condition is computer commanded.


Is there a switch or a button that lets you disable the overdrive gear (the top gear)? If so, check to make sure the switch is in the position where overdrive is enabled. There should be some kind of dashboard indicator that tells you when overdrive is disabled. Some vehicles have the overdrive control in the gear selector. If your car has this, “D” is drive without overdrive, and there will be some combination of “OD.”

Is the car safe to drive before it is repaired?

Is the car safe to drive?

I have no idea. I would need to see the car or get the answers to some questions in order to know.

Have you checked to make sure you didn’t accidentally disable the overdrive? Have you checked the condition and the level of the transmission fluid?

There is not overdirive switch, and the car was in ‘drive’ as normal. The transmission fluid is full.

BTW I appreciate your assistance with this question.


How does the transmission fluid look in terms of its condition? Does it look clean and red in color, or does it look old and brown? When was the last time the transmission was serviced?

These questions are really academic at this point. You need to take the car to a trusted mechanic to get it checked out. Don’t go to Aamco.

I’d bet there is an “overdrive lodkout” somewhere in the car!!

Since this is a Chrysler the overdrive lockout is probably on the dash.

Hey, hbune, did you ever find out what was wrong with your 4 speed transmission??

Probably no one will read this since it is several days old, but I kinda think the problem is in the TCC, not locking up.

Yes, you can drive the car but keep it below 60mph. The car is not worth the cost of rebuilding the tranny… But don’t let that stop you…

Have the trans checked for error codes. You may need an input and output shaft speed sensor. Easy to relpace on the transmission. I just did mine myself for about $50. Worth a try. Some auto parts stores will scan you car for free. If you get a code post it here. Good luck.

Doubtful on the speed sensors since the problem only seems to be in O/D. Faulty speed sensors usually result in limp mode. Very doubtful on TCC lockup since he is describing laboring engine and 500-1000 rpm increase. There wont be this much increase with TCC especially with this transmission since the converter clutch on this unit has what we call “partial lockup” This means the converter clutch starts locking up in 2nd gear and is fully locked up in O/D. I still think he needs to scan first, drive it, capture a movie and see whether this is a commanded condition. I still think its an overdrive problem.


I don’t see how the engine would be “laboring” if it is doing 500 to 1000 more RPM. Also if it STARTS locking up in 2nd gear, and is FULLY locked up in in OD, does that mean it “slips” (partial lockup) in 2nd gear and stops “slipping” (fully locked up) in OD?

My Dodge does not lockup in 2nd gear, only in 3rd and 4th. When the torque converter unlocks in 4th, there is a conciderable rise in RPM. I don’t have a tach so I don’t know how much.