Strange behavior in reverse only, 42RLE and 4.0

[TexasTJ2004]

Hi Guys,
I am seeing something strange on my TJ.
It shifts into Drive (from Park or reverse ) or into Reverse (from park or drive) little slow - I hear it very well, it takes like 3 seconds of noise. And when I am putting it into reverse, especially with a lot of gas or backing up uphill ( like my driveway), the whole rig shakes and makes strange noise.
I have no complains on the transmission in other situations, like the overdrive works well etc.
Is this something that you guys seeing as well?

 

[TexasTJ2004]

Continued to investigate this - it seems like the problem is only when I backing uphill and when I am at very low speed. Seems like something is slipping inside the transmission or something.

 

[Jerry Bransford]

Have you checked its ATF level yet? The engine must be running and the transmission in Park while checking it with its dipstick. The ATF level must be all the way up to the full line. If it's low add enough ATF+4 (only!) to bring it to the full mark.

 

[TexasTJ2004]

When the engine and transmission are hot (driving at least 10 minutes, parked, restarted after 5 minutes),engine temperature at 210, I see that the ATF+4 (I use Mopar one, that says ATF+4) level is between cold and hot. Was right in the middle. I guessed that this means that I don’t have enough fluid, so started to add a little. Will retry the experiments when my fluid level is precisely at Hot when the transmission is hot.

 

[Jerry Bransford]

Where an automatic transmission is concerned it's far better to be slightly overfilled than slightly underfilled.

 

[TexasTJ2004]

Where an automatic transmission is concerned it's far better to be slightly overfilled than slightly underfilled.

I never thought that 42RLE could be THAT sensitive..

 

[Jerry Bransford]

I never thought that 42RLE could be THAT sensitive..

It depends on how far below the full line it is.

 

[Not_Invented_Here_]

Continued to investigate this - it seems like the problem is only when I backing uphill and when I am at very low speed. Seems like something is slipping inside the transmission or something.

Are you ever marking sharp/full turns when it happens? turning hard as you reverse into the driveway I mean, or turning sharply into the driveway going forward

 

[TexasTJ2004]

Are you ever marking sharp/full turns when it happens? turning hard as you reverse into the driveway I mean, or turning sharply into the driveway going forward

I have double checked it. It happens when I drive straight back, uphill. Regardless of steering angle. I have read a theory that pump intake is at the back of the pan, and if you backing up uphill, and your fluid level is low, you might get into not enough transmission fluid pressure. I am filling it up, as Jerry’s recommendation above, and will retry this

 

[TexasTJ2004]

@Jerry Bransford - I have found what the problem is. The Transmission fluid is leaking from the front radiator (the bottom section, driver side, where the hose is coming from 42RLE). This might explain why I keep adding fluid, but it is never filled properly.

 

[TexasTJ2004]

Just to update the thread - i have filled the fluid coorectly. The problem with reverse is much smaller, and usually happens only on very steep incline, like backing up steep hill. Just backing up to my driveway is completely fine now. Hope that i didnt cause too much of damage with low atf+4.