Please Help

[nreddick]

i removed my front driveshaft in my 2002 Mercury Mountaineer AWD and now when i put it in reverse and go to back up it doesnt mov at first. i hear a whinding sound the engine revs up and then it starts to move. any ideas?

 

[Curtis]

Ive heard of people removing the front drive shaft in 4x4 vehicles, but not AWD
were you doing burnouts? not recommended

I cant see taking the drive shaft out causing the trans not to go into reverse.
Ive read the AWD system is not computerized, its all mechanical, so technically the trans should not know anything about the removed drive shaft.

Unless some speed sensors on front vs rear are detecting something abnormal but I doubt that.

I think you're only test is to put the shaft back on and see if it goes back to normal.

 

[imp]

Ive read the AWD system is not computerized, its all mechanical, so technically the trans should not know anything about the removed drive shaft. You read it right; AWD uses a tiny "torque converter" (viscous clutch) to absorb speed differences which occur between front and rear driveshafts. This is why AWD can be driven on dry pavement, while conventional 4WD must not: those speed differences on pavement can subject the driveline to potentially damaging torque levels, to say nothing of scuffing the hell out of the tires.

Unless some speed sensors on front vs rear are detecting something abnormal but I doubt that. The ABS sensors willbe telling the PCM their normal tale of axle speeds; that is independent of trans. output shafts operation. I know of no speed sensing being done between front and rear transfer case output shafts. The trans. itself has 3 speed sensors, one being an output shaft sensor, but it is unaffected by a missing front driveshaft.

I think you're only test is to put the shaft back on and see if it goes back to normal. Agreed......

 

[nreddick]

i removed the front drive shaft due to bad cv axles. they were binding up really bad one night so i had no choice but to take out the cv axles because i had to get to work the next day. going from a stop into drive it doesnt do this. only when going in reverse. and again not everytime. if i drive it for a little while (i.e. 15 mins) and put the truck in park and then go to reverse and back up it is fine. no hesitation.