After making a left hand turn and then straightening the wheel the transmission just disengaged from reverse, drive, overdrive, 2, or 1. There was'nt any noise or clunkiness before transmission gave out, while parked you still can hear the rpm range change when shifting through gears, but no response from the transmission. Several people have thought be a vaccum leak, if so where do I start looking for it. I changed transmission fluid and filter and checked pump, there was'nt anything in the pan parts wise, please help, thank you!

Bad bearing?

Sounds like the bearing in the overdrive if it was the front bearing on a four wheel drive car that would still make the noise going around corners go back to the dealer and go on a test drive with the mechanic you drive and recreate the circumstances

The short answer, yes. M46 models with the type J or P overdrive (depending on year and market) require a certain level of oil in the overdrive. Additionally, the overdrive is a lot like a standard automatic transmission with one gear range in theory of operation. Therefore, the hydraulic properties of said transmission do come into play here, line pressure, shifting pressure, accumulator and piston function all work together to engage or disengage the unit. Always ensure the unit is disengaged before downshifting and of course, shifting into low reverse.

Yes when you park on an incline you should always put your emergency brake on before shifting to park. Then whenyou are ready to move again put you car in gear before disengaging the emergency brake. this will remove the stress from the transmission.

it may be a bad transmission modulator valve located on the side of your transmission,vacum operated. a sudden downshift or forward shift when unexpected is sign of a bad modulator valve or a vacum leak to the transmission.best to shop around for a garage w/references when it comes to transmission work though. check all the vacum lines to your transmision,you need to look on the underneath side of your truck on the side of transmission for a loose or disconnected vacum line on the side of the transmission. when you feel the vacum line,follow it to the top of engine,the vacum line is about 3/8th line,and may be disconnected or losing air. to make this short,when you drive the car,start out in low gear and shift the transmission,manually from 1st to 2nd to 3rd does it do right with no slipping? if it does this right and shifts great manually,the modulator valve on the side of the transmissions bad,or a bad vacum leak in-between.thank you for choosing fixya.com

possibly a transfer case motor problem make suer you are in 2 wheel drive,try shifting button from 4 wheel to 2 wheel drive and make sure your tow haul switch is off on the end of the regular shiter

bad relay switch

High to low /low to high ratio, you will need to be stopped and the transmission in neutral for this to be changed.
The 2wd - Auto - Lock switch can be switched at any time, as it operates an electromagnetic clutch - 2wd is rear wheels driving only - Auto - is to automatically engage 4wd when wheel slippage is detected (this also happens when turning at intersections, due to the inside wheels having a shorter path to the outside wheels, and can give a binding effect on sealed roads (I don't drive with it in auto on sealed roads) auto is excellent if you get, or expect wheel spin from an intersection when wet, just flick it on before or when you have wheel spin, also on gravel roads, having it on auto will greatly reduce the sliding of the back end, and make the car noticeably more stable.
Lock - this locks the differential, which further reduces wheel spin, when in mud / snow, but this will also make the car not want to turn corners, due to it resisting the different distances traveled by the inside and outside wheels.
A/T switch - this actually has 3 positions, and changes the shifting points of the automatic transmission - the middle is normal - Hold is to hold the gear longer, to improve fuel economy, and not change down (kick down) as quickly - Power has the opposite effect, it makes the transmission change down sooner under acceleration.
Also the O/D (overdrive) button on the side of the Tee shift lever, is to engage / disengage overdrive (5th gear) - never do heavy towing in overdrive, this will cook the transmission and overheat the engine (due to the radiator being used as a heat exchanger for the transmission fluid.
Another little quirk - if the transmission light starts flashing every 40 to 50 km, this can indicate that the wheels are different diameters (a flat tyre, or tyres have been swapped around and the spare is more or less worn than the other tyres), the computer will pickup that the wheels are turning at different speeds.
When cold, it is normal for the transmission to stay in 3rd (2-3 minutes of driving), until it has warmed up, and then stay in 4th for a few more km's (5-6 minutes), before it has warmed up enough to change into 5th (overdrive).

most 4x4s have to go in reverse to disengage from 4 wheel drive to 2 wheel drive.

well the low cost way to go first would be to try and change the trans fluids. If the problems still remains the it may be an internal problem