I have a 99 cummins with a built 47re tranny and i havent had a prob with it till i changed tranny fluid and now it slips on hard take offs and pulling heavy loads. I used lucas simi synthetic tranny fluid could that be my prob i have a gov pressure sensor high code need help adap

 

Is the Lucas oil rated the same as ATF+4?I would be really easy on it untill you figure out what's causing it.

 

Is it shifting and slipping when driving? If not, your clutch packs are fine.

Are you sure the fluid is topped off?

Make sure from now on, use Dex/Merc Mix Transmission Fluid.

Did you put a new 2+ clutch torque converter in with the build transmission?

 

Its got a bd triple disk converter and the only time it slips is hard takeoffs and when i pull my camper up hills

 

What else is done to tranny? just converter? valve body or shift kit? Always run full syn (atf+4) trans fluid, seeing that is what they call for.