P0734 code related to not shifting to 4th gear??

[lao]

Hi. I am having a problem with my Discovery II 2000. My trany is not shifting to 4th gear. I am getting a code P0734 (incorrect 4th gear ratio). I was told this code is related to a problem with the MAF. I've cleaned and after few miles I get the code back. I am just concern about buying a new MAF just to find out my trany problem is not solved by replacing the MAF. So I am curious to know if anybody had the same issue and was really solved by replacing the MAF. It is still odd to me that a intake sensor can affect the transmission, but what do I know right??

[Hammer38]

P0171/0174 would be related to the MAF. This code was a new tranny under warranty. Consider a rebuild or buya junk yard one.....or just live with the problem.

[j visci]

Usually if it is the MAF it would be accompanied by the P0171/P0174 lean codes as stated above.

Drive it in D3 and see if you get a good torque converter apply(you will see a drop in RPM a bit after the 2-3 shift. It should almost feel as if you just shifted into another gear.) If you do click it up to D4 and see if it shifts into overdrive and the converter locks up again.

Check the usual stuff too like the battery, grounds and fluid level/condition if you have the ability.

How many miles on the truck?

[lao]

112K Miles on it. Its weird because yesterday it made it to 4th gear w/o problem.... I was suggested to make a "maintenance" job to the tranny, oil/filter and clean up... I am thinking about this since its going to be a lot cheaper than buying a new or used tranny...will see how that goes.

[j visci]

Have your mechanic add some LubeGard to it. In the red bottle. Sometimes it can free up debris in the valve body and solenoids on higher mileage vehicles. Its worth a shot if the fluid and filter are getting serviced anyhow.

Good luck.

-Jim

[Hammer38]

Have your mechanic add some LubeGard to it. In the red bottle. Sometimes it can free up debris in the valve body and solenoids on higher mileage vehicles. Its worth a shot if the fluid and filter are getting serviced anyhow.

Good luck.

-Jim

Is that the Lucas Oil additive? I used their P/S additive on a few old Disco & P38 steering boxes and it not only quieted them down, but actually stopped a few leaks.