Weird humming noise when AW4 shifts to OD

[Fred85]

Under mild acceleration, my jeep will normally shift to OD between 45 and 50 mph.....rpms will be about 1500, if not a tad more

this sound is hard to describe, its a hum/sputter sound almost like the engine is trying to stall but it runs absolutely fine

i was thinking a trans mount or engine mount could be the culprit?? but i'm not sure 01 xj, 69k miles

[jeepdude10000]

mounts usually make a clunk, not hum, have u checked your fluid?

[Fred85]

fluid is fine, semi-fresh

it sound as if it's almost shifting into OD too early.........but the kick-down cable is adjusted properly per the fsm

[jeepdude10000]

mine kicks in about the same speed but it does not make any sounds or noise at all, mind u im running lucas tranny add.

[lawsoncl]

The tranny cable does not affect the shift points, just hydraulic pressure within the tranny and hence shift firmness. The trans computer uses the input/output shaft speeds and the throrrle position sensor (TPS) to determine shift points. I'd say 95% of shifting problem are the TPS sensor.

[Fred85]

excuse the ignorance, i can clean the tps right??

[logdog]

excuse the ignorance, i can clean the tps right??
Yes

[jeepdude10000]

but TPS has strips of metal in it, they usually wear out. and they are sealed so how do they get dirrty?

[lawsoncl]

They do wear out, especially if you're one of those drivers that just can't keep their foot still. :} The TPS isn't sealed very well as there are many, many reports of people killing them wil pressure washers or water crossings. They don't come apart without some cutting.