Dexron VI in GM A5S390R (GM 5L40-E)

[Ghost-Flame]

Originally Posted by upallnight

What about the front wheels?

Do a drain the day before and let the truck sit over night. Even though you may have drain the fluid out of the trans a larger quantity of fluid is still in the Torque converter and trans cooler.

The next day. Start adding ATF to the trans with the engine off until it comes out of the fill hole. Replace the plug, but do not tighten. Start the engine up and go through all the gears pausing at each gear for about 30 seconds. With the engine still running and the truck in park or neutral crawl underneath the truck, remove the fill plug and continue adding ATF until it starts coming out the fill hole again. Replace the fill plug and tighten to the appropriate torque. You are now done. If you follow this procedure you should be well below the limit of the trans temp that is not to be exceeded while filling the trans. Remember ATF expand with heat and the hotter the ATF is in the trans the less ATF you will be able to get back into the trans.

I was assuming the poster knew how to replace the fluid and was asking about how to check the level when hot.
Just for the record I change the fluid, drain and fill, 3 times removing the pan all 3 times. I figure I get 90%+ of the old fluid... maybe more.
All fills running the engine and transmission like described. On the third fill I do the more precise level check. All pathways lead to a similar result. Keep on truckin.

[Ghost-Flame]

Front wheels don't need to spin. Those are resting on blocks to keep trans level.

[upallnight]

Originally Posted by Ghost-Flame

Put your car up on jack stands so the rear wheels are free to spin. After filling with Tran fluid. Run/idle engine and gently shift Trans through the gears. Park, reverse, drive. Let engine idle with the Trans in dive and rear wheels spinning fo 10 to 15 minutes. Then shut car off . Place in park. Check fluid level.
The hot fluid will expand and the excess will flow out. When it stops running out. Replace the fill plug and it's right. If you suspect a leak check in 30 to 60 days.

**FYI. My Trans at 175 000miles. Seems to use about half a qt in 90 to 120 days (10000 miles) with no external leaks that I can find. I don't know where it goes but it just keeps running like new. So I just keep checking it.

The only problem I see with your procedure is that if you shut off the engine, the pump in the trans is not operating so all the ATF will drain back into the pan and when you go to check out the fluid level, a LOT of ATF will come rushing out and if you wait until the fluid stop and replace the plug, your trans will not be at the correct level. If I'm wrong I hope other people chime in, but I think I'm right.

[Ghost-Flame]

You are right . Had a brain fart.

[GunnyGlow]

Originally Posted by Ghost-Flame

Front wheels don't need to spin. Those are resting on blocks to keep trans level.

Can you explain? I didn't think this was a recommended procedure with XDrive.....?

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[upallnight]

I always thought our truck were All Wheel Drive (AWD) so all four wheels will always be turning.

[Ghost-Flame]

No. When the sensor detects a a slip it sends power to the front wheels otherwise in normal driving conditions the rear wheels are powered only.
On the jack stands the only the rear wheels will turn. Especially at idle speed you aren't going to trigger a sensor.

[upallnight]

Originally Posted by Ghost-Flame

No. When the sensor detects a a slip it sends power to the front wheels otherwise in normal driving conditions the rear wheels are powered only.
On the jack stands the only the rear wheels will turn. Especially at idle speed you aren't going to trigger a sensor.

According to an article by 4WDonline our BMW has a full time four wheel drive system. There is a spilt in power between the front and rear wheels, but the system is full time.

BMW X5 4x4

[GunnyGlow]

It is my opinion this is bad advice to recommend raising the rear wheels and allowing them to spin, even if that is possible. I think it can happen but is very bad for the clutch packs in the transfer case for the same reason the X5 must be towed on a flat bed.

Seems pretty dangerous as well.


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[JCL]

Originally Posted by Ghost-Flame

No. When the sensor detects a a slip it sends power to the front wheels otherwise in normal driving conditions the rear wheels are powered only.
On the jack stands the only the rear wheels will turn. Especially at idle speed you aren't going to trigger a sensor.

Pre x-drive (up through 2003) don't have sensors in the transfer case. In normal driving all wheels are powered.

The transfer case will work like an open differential, so if there is a slight drag on one axle the wheels on the other axle will turn (ie at idle). But as soon as the speed differential is sufficient for the DSC system to apply a wheel brake on the spinning wheel, that will change. That is when the vehicle drives off the jack stands.

It is dangerous to suggest that anyone work on an AWD vehicle with the front wheels on the ground and the rear wheels hanging, with the engine running and the transmission in gear. It is even worse to suggest that someone may get underneath that vehicle. Don't even try and justify that 'it will be fine'. It is simply a very bad practice.