The reverse gear is slipping a bit and when I checked the fluid it was way overfilled. I checked it both hot and cold and both times it was all the way up to the "do not add" section of the dipstick.

So my question is... Would too much fluid in the transmission cause it to slip in gear?

 

Does it slip in any other gears, besides reverse? If not, then the overfilled fluid might not be the issue. I have heard that overfilled transmission fluid can cause foaming of the fluid and subsequently oil starvation which can kill the trans, but I personally would think if that was happening, you'd notice it in drive as well. Also, how does the fluid look? Is it a clean bright red color?

Back in 2012 as a dumb 17 year old: I did a trans service on my 2007 myself and went waaaaay overfilled on the transmission fluid. So full in fact, that if I went WOT, it would spew transmission fluid out of the dipstick tube, lol. Didn't even bother checking it until I had gone way too full with it. I hate to admit I was that stupid, but I was. It never had any noticeable issues though (thank God). Only thing I noticed is it shifted harder. I went and bought a pump with a hose down the filler tube to suck out the excess. That was at 70,000 miles and nearing 160k now, the trans is still fine.

Friend of mine with his 2007 a year ago experienced slipping in reverse and his ended up being a broken reverse band. I think something like that would be more likely. Another possible cause could be the filter has fell into the pan. They can slip out of the filter opening if they are not properly seated into place. Again though, it should be noticed in drive, as well. Overfilling trans fluid usually ends up getting blown out of the dipstick tube like mine did, if it's *severely* overfilled. Still, it can't hurt to pump some out and get it down to the normal fill range and see if it makes any difference.

 

Not likely unless it was compounded by other issues. Do you know how it got overfilled? With 4WD systems the gasket between the t-case and the tranny can leak and allow fluid from the t-case to enter the tranny...causing the overfill. This in turn can cause issues with the t-case since it's running low on fluid.

 

It shifts smoothly, but it seems taking off in drive (1st gear) could have a little more pull. Possibly slipping only slightly? The color of the fluid is like it was just piurep in. Perfectly pink/light red.

I was doing some online perusing of overfill symptoms and I ran across several articles that said slippage may occur as a result of overfill. Reading through the owner's manual, it also states that overfilling the transmission may result in gear(s) slipping. I'll be pulling out at least a half of a quart today and then I'll test it out .

 

Once you remove the excess fluid, if the slipping gets obviously worse following the removal of fluid; the filter just might be in the bottom of the transmission pan. Just a guess. One thing you could do once removing the fluid is start off from a stop on an incline and see if the slipping gets worse and starts bumping or jerking around like it's tryin' to jump in and out of neutral. That could be a sign the filter has slipped out of place and losing suction of the fluid. Has the trans been serviced, that you know of?

 

Removed about 24oz of fluid using a cheap hand pump from AutoZone (it worked great, and only $15). Got up this morning and went out to check the fluid level around 9 AM. Left it parked on level ground all noght. The fuid was so high that it registered almost to the top of the "Do not add" section of the dipstick! After removing the fluid it registered right in tge middle of the "cold" portion of the dipstick. After a 20 min drive around town it registered in the upper third of the "hot" portion of the dipstick.

The transmission still seems to slip in reverse, but felt a bit better off the line. Still shifts like butter in forward gears. I was able to see the code it threw when I tried backing out of a downhill parking spot yesterday. P0722 - output speed shaft sensor. I'll change that sensor out, since it has a plastic gear on it . Perhaps it is starting to wear out? However, it's most likely the reverse band. In that case I'm just going to get a remanufactured transmission. What's another $2000?? :-\

 

Are you checking the fluid level with the engine running? If not, your readings are going to be very high.

If the transmission is really slipping it's time to replace it.

 

I checked it both cold and hot . The dipstick has two sections, one for s cold check and the other for hot. They both indicated a high level. The cold check showed in the "do not add" section at the top of the dipstick, which is about 2" above the cold line. While hot it indicated above the entire plastic portion of the dipstick, all the way up on the metal part. Both times the engine was running.