[Tesler32]

I have an 06 G6 with the 3.5 v6 RPO MN5 which should be the 4t45 trans.

I am having hard shifts and I live in ohio and today I was driving back home in the rain and the car would basically not shift getting onto the freeway, but at slower speeds it would snap you back in the seat when only barley getting on the gas. The hard shift happened once a few weeks back was also in the rain but I didn't think anything of it until it was non stop on the way home. Once I got off the freeway about 45 minutes later it shifted fine all the way the rest home but was only a few minutes and a handful of shifts. I noticed this thread and TSB on ALLDATADIY and was going to take the day off tomorrow and see if I can find a break in any of the wires in the harness. If anyone out there is seeing this and has any incite on what to do or look for that would be greatly appreciated.

 

[Tesler32]

I would encourage you to take it to someone that can read all the car's codes. In other words, has a proper scan tool.

Do you have that bulletin number you refer to?

I took today off to take my car to my dad's garage and I had a chance to check over the car and hook up to his scan tool and take a test drive. I had two DTC's. P0752 and P1750 both are related to 1-2 Shift Solenoid. I have about 120k on the car and I had trans flush/fill at 80k since I tow two skis with the car in the summer months. The hard shifts/no shifts are spotty at best right now. I am leaning toward dropping the trans and replacing 1-2 SS and maybe even getting a new wiring harness while I am in there. Got a quote from a local dealer at it was 6hr $750 total to do the work. So I would definitely be doing it on my own, but please let me know if anyone has any info that would be helpful in my case.


PS. In my road test the 1-2 SS was working correctly so I cleared codes and it hasn't shown up again yet, but I'm sure it will soon. I also checked the trans fluid level and it was good and the fluid looked good as well.

 

[Tesler32]

Update: Yesterday I was over at my dad's shop and I hooked the car back up to the scan tool and I go P0753 which is the 1-2 Shift Solenoid Circuit. I tried to test the circuit and of course it failed. I now don't have 1st or 4th gear at all. They were shifting before but just harsh. Now I got nothing. So I went ahead and purchased two Shift Solenoids and the Trans wire harness and I am going to drop the trans out tomorrow to replace all 3 parts. I figure while I'm in their I'm not gonna replace just the one SS and why not replace the wire just in case something is damaged like in the TSB No. 06-07-30-034 for the MN7 Trans. I figure if GM messed the wire routing up in one model they could of done it in mine as well and just not had enough cases to issue a TSB for the MN5 trans. I thank everyone for the help and I will post on Sunday with the results of my trans tear down. Should be FUN! Yea!!! sarcasm...

 

[Tesler32]

Well I lowered the engine cradle and removed the valve body cover and replaced both shift solenoids. The 1-2 solenoid what shorted out and melted. Car is working great now.

 

[Tesler32]

There are 4 main bolts 18mm heads. The fronts are under the plastic shrouds right behind the fog lights. The rears are in plane sight to the left and right of the exhaust pipe. There are two additional bolts along with the rear engine cradle mounts. The steering rack is also mounted to the cradle so you have to remove the 3 nuts and two long bolts from that as well. There are the engine mounts to remove. Basically one on each side of the motor. Finally the sway bar and lower control arms are all that's left. She will drop right out after that so the motor has to be supported properly.