ATF smell in cab with 6spd G56

[tron1959]

I changed the ATF in my G56 about 2 months ago. Only short trips since until last tuesday. We hooked up to our horse trailer which is about 7,000 lbs empty. We had a 400 mile roundtrip. The second half of the trip we were loaded with two horses, so add about 2000 lbs on return.



About halfway there we stopped at a rest area and I noticed for the first time the ATF smell outside of the truck. I crawled under the truck and placed my hand on the transmission. It was hot but I was able to leave my hand on it for several seconds so I was not concerned it was too hot. I also observed no leaks.



We continued on our trip and now the smell was noticeable for the remainder of the trip in the cab. The transmission is not making any unusual noise and shifts just as smooth now as when new. I did notice a few weeks after changing the fluid a faint noise coming from the transmission best described as "shhhhhhhhh". I can hear it backing away from our house. If I press in the clutch and shift to neutral the noise quits while it is still rolling.



I used Valvoline ATF+4 fluid for the refill. This was the first time towing anything since the fluid change.



Has anyone else experienced this smell while using Valvoline or any other brand. I don't know if something is wrong with my transmission or if the fluid just smells much worse than the factory fill.

 

[steved]

Are you sure it was the trans and not the power steering??

 

[tron1959]

No I'm not sure. The booster is leaking in the cab a very small amount. It has been doing this for quite some time and doesn't seem to have increased. I don't see where it ever leaked enough to drip. I will look into this more tomorrow to eliminate the booster if the leak has not increased.



I also looked under the truck and under the hood and don't see any leaks.

 

[RShipp]

There is also a boot that is very prone to ripping on the shifter tower. Maybe where the smell is coming from.

 

[bwall7116]

There is also a boot that is very prone to ripping on the shifter tower. Maybe where the smell is coming from.

I agree here this is most likely the problem. Take a flash light and a mirror and inspect around this area on top of the transmission and you will probably see a wet spot. I have also heard that the early G56 fill plug was placed too low in the transmission and does not allow it to be filled with the full 5. 6L it is specked for. Since you just changed yours I would definitely make sure you got it all in there. I heard some guys pour it in from the top throught the shift tower but I would think something like the angled funnels the NV 5600 guys use would be the easier route.

 

[tron1959]

I was able to refill with 6 qts.



I removed the tray around the shift lever and attached is a picture showing the rubber boot that seals to the floor. There are no holes or crack but as you can see it does not seal around the shift lever. Should there be an airtight seal here?



I also looked under the truck with a flashlight and a mirror but was unable to see any leakage around the shift tower.

 

[bwall7116]

Pretty sure it is supposed to seal up around the larger part of the shifter. Over time the boot may have just collapsed a little. I would try pulling it up just far enough that you can zip-tie or hose-clamp it around the wide part of the shifter. In your case thats all I could think to do since it sounds like its filled with the right amount of fluid and the orange boot isn't torn.

 

[tron1959]

Shift Boot

Thanks. I will try pulling it up. It looks like the two tabs on each side are meant for just that. To help with installation at the factory. It appears it should be pulled to the top of the larger diameter portion. I don't know it the boot will stretch that far. If not I will zip tie it as you recommend. I wish I had access to a shop manual. It would probably show how far the boot should be pulled.



Thanks,



Ron

 

[RShipp]

There are 5 or 6 bolts under the carpet. You have to pull it back to get to them. The shifter has 2 boots. When you pull the second one you will be able to see the floor under the truck and you will see the red colored boot that is probably torn.