4th to 5th gear slip / overrev

[Adam Janowski]

hello all

2015 explorer 3.7 with 6 speed trans.

had the ford power train module reprogramming a couple months back (a recall i think) and that seemed to really add smoothness when shifting to D or R from park - less slamming into gear at times - and also smoothed out a downshift into 2nd gear under light uphill throttle.

not intermittently, i get a slight overrev or slip on a 4th gear to 5th gear shift on light acceleration. might do it one out of 10 times and usually in the morning when colder.

just a slow and constant acceleration up through the gears and not changing throttle input during the shift.

has anyone experienced anything similar? more curious than concerned - thx!!

 

[BrooklynBay]

Did you check the fluid level?

 

[Adam Janowski]

fresh fluid 6k miles ago just after purchase. did it myself and the level was perfect after driving. a pain to check as have to remove airbox to do it properly as dipstick is under it. need to have engine running in neutral with vehicle flat and air filter removed, but intake and maf need to be connected. haven't checked fluid level since, but no sign of leak at trans and no shift quality issues but the one described. in fact since i got the vehicle, and after the ford reprogram, the shift qualities overall seem slightly improved

 

[BrooklynBay]

Try Lubegard additive. Which brand was the fluid? Was it synthetic?

 

[Adam Janowski]

I'll look into the lubeguard additive.

i changed the trans fluid 6k ago, at 125k, as i wasn't sure when last changed. I used Merson LV as per the OEM spec. not sure if that's synthetic or not.

the fluid I removed actually looked quite good. i sent it off to blackstone labs and the attached report stated overall good condition as indicated by the foreign particulates in the fluid upon lab analysis.

 

[BrooklynBay]

The earlier models had servo bore wear issues. I'm not sure if that issue was corrected in the later version which you have. Those models have a band adjustment too. What is the model number of your transmission?

 

[03WIExplorerLtd]

5 speed in 10 and under had servo bore issue. Had 2 of them have the issue.These 6f50 while clunky are times are a solid transmission