Trans 68rfe not shifting to 6th

[JPena]

Currenty having issues with the transmission not shifting to 6th. Started about 3 months ago but it was every now and then. Now it is more frequent. To resolve i have to almost come to a compete stop or until it downshifts then it seems to shift normal after that. I changed the filters and fluid at 75k and 160k. didnt see anything in the pan during those changes. Just passed 200k. After searching the forum i did not see anything with this specific issue. I do not do any heavy towing and it seems to happen during normal acceleration. Also it does not throw any codes.

 

[JPena]

2009 Dodge Ram SXT Quad Cab 4X4. 6.7L Stock

 

[Hoefler]

That transmission has a 60,000 mile service interval. What fluid did you use?

 

[transe]

If there are no fault codes, then I suspect you may have a flaky throttle position signal. Do the other upshifts seem late / delayed? Do you get Torque Converter Clutch (TCC) engagement (lockup) while in 5th gear? I presume you're not running in Tow/Haul mode?

 

[JPena]

All upshifts seem to feel normal and I do get TCC lockup in 5th. Not in tow/haul mode. Happens a couple times a week now.

 

[transe]

All upshifts seem to feel normal and I do get TCC lockup in 5th. Not in tow/haul mode. Happens a couple times a week now.

OK, if you're getting TCC engagement then that rules out one possibility. The trans will not shift into 6th gear until the TCC engages, so if something were inhibiting the TCC lockup that would also inhibit 6th gear. But it sounds like that's not the case.

Do you have any kind of scan tool that can display the throttle reading? It might help to watch that and see if something screwy is going on when it refuses to upshift. That's really about all I can suggest. The 5-6 upshift point should depend on output speed and throttle opening. If your output speed readings were flaky, then you should be setting Gear Ratio Error faults (since that would make the TCM think the trans is not at the correct ratio). So since you have no faults, the throttle signal is the only thing I can think of that might cause the problem.

Is your trans temperature reading OK? And not at some high value (240°F or higher)?

 

[JPena]

Thanks TransEngineer. Temps are all normal. I have a scan tool and will pay closer attention next time to the throttle reading when it happens. With 200k would it be wise to change the valve body or just wait until symptoms arise? I have read differing opinions on this.

 

[xcc_rider]

That transmission has a 60,000 mile service interval. What fluid did you use?

This is an older post from TE on a different forum: (irrelevant content deleted)
ATF+4 is a premium fluid and in fact, the change interval for "normal" service is 120,000 miles. You only need to change it at 60,000 miles if you do frequent trailer towing or other heavy use

 

[transe]

Thanks TransEngineer. Temps are all normal. I have a scan tool and will pay closer attention next time to the throttle reading when it happens. With 200k would it be wise to change the valve body or just wait until symptoms arise? I have read differing opinions on this.

If the valve body has not been replaced previously, then yes, for a 2007-2009 MY truck (with 200K miles) I would definitely recommend changing it.

 

[JPena]

Thanks. Will be my next purchase. Looking at a revmax with solenoid.