08 hard shift

[T90123]

I have a 2008 2500 with 68rfe in it. This is the first diesel truck I've ever owned so I'm still trying to learn things about them with tuning/modding.
I tuned the truck but its very mild and I put the REVMAX towing/hd valve body with new OEM solenoid in it. The truck has always had a relatively hard shift into 5th but its pretty inconsistent,
about the only way I replicate it is by taking an entrance ram onto the highway when I'm just trying to accelerate a bit to get up to speed with traffic (70-75mph). The truck was tuned before the new valve body was put in and my line PSI stayed about the same after it when shifting. Do I need to get another round of tuning for the valve body? Also was the valve body upgrade the right call to try and fix the hard shift or are there better things I can try?

Also new to the forum thing my bad if I posted this in the wrong area.

Any insight would be awesome.

 

[Fast69Mopar]

I have a 2008 2500 with 68rfe in it. This is the first diesel truck I've ever owned so I'm still trying to learn things about them with tuning/modding.
I tuned the truck but its very mild and I put the REVMAX towing/hd valve body with new OEM solenoid in it. The truck has always had a relatively hard shift into 5th but its pretty inconsistent,
about the only way I replicate it is by taking an entrance ram onto the highway when I'm just trying to accelerate a bit to get up to speed with traffic (70-75mph). The truck was tuned before the new valve body was put in and my line PSI stayed about the same after it when shifting. Do I need to get another round of tuning for the valve body? Also was the valve body upgrade the right call to try and fix the hard shift or are there better things I can try?

Also new to the forum thing my bad if I posted this in the wrong area.

Any insight would be awesome.

Hard shifts with an RFE trans can come from a few things. The first thing you need to see is the CVI's or Clutch Volume Index. This is the adaptive memory portion of the PCM/TCM. The clutch volume index is the amount of fluid required to fill a clutch for application. The harder the truck is driven the more amount of fluid is pushed into the clutch for it to apply.

Now, if you replaced the valve body and solenoid pack and you did not perform a quick learn then I would expect hard or inconsistent shift for a couple thousand miles.

A quick learn is how you reset the CVI's so each clutch has its base amount of fluid for application. If the truck has been tuned I would say it's time for a revision with the new valve body and solenoid.

 

[seanclark1503]

Ive got the 08 w/ 6.7 & 68 rfe also . It’s an awesome thing. Mine shifted not to my liking. I got a tuner that also lets you customize the firmness and at what point your trans. shifts for your driving style. I have no issues with my 6 speed now.