# Transmission will not shift into overdrive



## greg h (12 mo ago)

I have a 96 HB with RL4R01A transmission that will not shift into overdrive. I understand there is a TSB on this issue that I have not found. While driving under 50 mph transmission shifts fine & truck goes into overdrive no problem. Once I reach 51 mph truck downshifts & will not shift back to overdrive.


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## jp2code (Jun 2, 2011)

I don't know much about the operation of an automatic transmission, but they are very simple machines from what I am told. 

When others have had issues with their automatic transmission, one of the first questions is usually, "When was the last time you had it serviced?"

They have internal screens and filters that do not need to be replaced often, but they do require some maintenance. Clean the screen, change the filters, and flush out the old transmission fluid.


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## BRubble (Jun 22, 2014)

greg h said:


> I have a 96 HB with RL4R01A transmission that will not shift into overdrive. I understand there is a TSB on this issue that I have not found. While driving under 50 mph transmission shifts fine & truck goes into overdrive no problem. Once I reach 51 mph truck downshifts & will not shift back to overdrive.


Probly best to take it to Nissan or a Transmission Shop.

Whatever you do DON'T FLUSH THE TRANSMISSION FLUID UNLESS ABSOLUTELY NECESSARY. Many time's an Old Transmission that is Flushed will start Slipping, then will need to be overhauled or replaced.

It is possible that the Screen may be clogged, but that would just be dropping the pan, cleaning or replaceing the screen, and that is just a Drain and Fill - Not a Flush. If you drop the pan, use a New Gasket.

Follow the procedure in the Nissan Service Manual to the Letter when checking the ATF Level. When checking useing the Cold Range, Warm the Engine up to operateing temp, by looking @ the Coolant Gauge. I put the Level 1/2 between the Low and Full mark's on my '13. Again there is a specific procedure to follow in the Service Manual. It is important that the Level be correct for the AT to Function Properly.

My guess is that it is something else beside's the ATF though.

Good Luck,


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