C6 slow to go when cold

[Dorsai]

Note that I didn't say "flush" it. I do worry that doing so might dislodge things, but don't know that it will. However, if you just drain the transmission and the converter you aren't going to dislodge much. And changing the filter is a must as well.

Personally, I've vowed to NEVER pull the pan on one of these transmissions w/o installing a drain plug. I've made a huge mess in pulling the pans over the years, so I want to be able to drain it before pulling the pan. And for ~$14 delivered, this B&M one from Amazon looks good.

I've had a similar problem with my C6. In my case the problem was that in cold weather, putting the transmission into drive (or any other forward gear, but not reverse) would require waiting 1-3 minutes for the transmission to eventually notice and engage. I was told that the most likely cause of this was old seals.

EDIT: It was only the first shift of the day that was problematic. Even hours later on the same day going into drive would be fine - it was only sitting overnight in the cold that the problem appeared.

However...as part of my prep work for the trip out to Skiatook in 2019 I decided to change my transmission fluid - it looked fine on the dipstick, but I knew that it was at least 10 years old. After doing so (I dropped the pan and drained the torque converter, but did NOT flush the system) the problem appeared to go away - at the least I don't recall it happening this past winter. The weather here in GA is only just now getting cool enough for the issue to reappear, so I'll be keeping an eye out this time around and will report back.

The short version of the above? Change your transmission fluid, see if it helps. I used Valvoline MAX fluid.

[grumpin]

Note that I didn't say "flush" it. I do worry that doing so might dislodge things, but don't know that it will. However, if you just drain the transmission and the converter you aren't going to dislodge much. And changing the filter is a must as well.

Personally, I've vowed to NEVER pull the pan on one of these transmissions w/o installing a drain plug. I've made a huge mess in pulling the pans over the years, so I want to be able to drain it before pulling the pan. And for ~$14 delivered, this B&M one from Amazon looks good.

I like your thoughts on the drain.

https://www.amazon.com/c6-transmission-pan/s?k=c6+transmission+pan

[grumpin]

I've had a similar problem with my C6. In my case the problem was that in cold weather, putting the transmission into drive (or any other forward gear, but not reverse) would require waiting 1-3 minutes for the transmission to eventually notice and engage. I was told that the most likely cause of this was old seals.

EDIT: It was only the first shift of the day that was problematic. Even hours later on the same day going into drive would be fine - it was only sitting overnight in the cold that the problem appeared.

However...as part of my prep work for the trip out to Skiatook in 2019 I decided to change my transmission fluid - it looked fine on the dipstick, but I knew that it was at least 10 years old. After doing so (I dropped the pan and drained the torque converter, but did NOT flush the system) the problem appeared to go away - at the least I don't recall it happening this past winter. The weather here in GA is only just now getting cool enough for the issue to reappear, so I'll be keeping an eye out this time around and will report back.

The short version of the above? Change your transmission fluid, see if it helps. I used Valvoline MAX fluid.

That sounds good, and as Gary and you did I won’t flush it.

This morning it went right into gear.

 

[grumpin]

I've had a similar problem with my C6. In my case the problem was that in cold weather, putting the transmission into drive (or any other forward gear, but not reverse) would require waiting 1-3 minutes for the transmission to eventually notice and engage. I was told that the most likely cause of this was old seals.

EDIT: It was only the first shift of the day that was problematic. Even hours later on the same day going into drive would be fine - it was only sitting overnight in the cold that the problem appeared.

However...as part of my prep work for the trip out to Skiatook in 2019 I decided to change my transmission fluid - it looked fine on the dipstick, but I knew that it was at least 10 years old. After doing so (I dropped the pan and drained the torque converter, but did NOT flush the system) the problem appeared to go away - at the least I don't recall it happening this past winter. The weather here in GA is only just now getting cool enough for the issue to reappear, so I'll be keeping an eye out this time around and will report back.

The short version of the above? Change your transmission fluid, see if it helps. I used Valvoline MAX fluid.

That sounds good, and as Gary and you did I won’t flush it.

This morning it went right into gear.

Interestingly this morning it went right into gear, then I let the truck warm up for a bit, then it did not go into gear right away.

[Dorsai]

The weather here in GA is only just now getting cool enough for the issue to reappear, so I'll be keeping an eye out this time around and will report back.

So...it was 28 degrees this morning when I got up, perfect time to check this out.

The verdict? Went into forward gear perfectly. In years past it could take anywhere from 1-3 minutes to start moving forward in sub-freezing temperatures, but today it got going with no difficulty.

 

[Gary Lewis]

The weather here in GA is only just now getting cool enough for the issue to reappear, so I'll be keeping an eye out this time around and will report back.

So...it was 28 degrees this morning when I got up, perfect time to check this out.

The verdict? Went into forward gear perfectly. In years past it could take anywhere from 1-3 minutes to start moving forward in sub-freezing temperatures, but today it got going with no difficulty.

A C6 is a very sensitive transmission. I think they can sense a lot of things. I had one that wouldn't shift right so I pulled into O'Reilly's and bought a bottle of Sea Foam. Walked out, laid it in the seat, and started it up. The tranny never missed a beat after that.

But I put the Sea Foam in anyway later that day.

[Dorsai]

A C6 is a very sensitive transmission. I think they can sense a lot of things. I had one that wouldn't shift right so I pulled into O'Reilly's and bought a bottle of Sea Foam. Walked out, laid it in the seat, and started it up. The tranny never missed a beat after that.

But I put the Sea Foam in anyway later that day.

In other words, buying a bottle of Sea Foam is analogous to Mom threatening the kids with cod liver oil? I've heard worse theories.

[Gary Lewis]

In other words, buying a bottle of Sea Foam is analogous to Mom threatening the kids with cod liver oil? I've heard worse theories.

Yep. Works every time. But I'm doubting your mother did that. However, I'd bet your grandmother did. Tell her hello for me.

[Dorsai]

Yep. Works every time. But I'm doubting your mother did that. However, I'd bet your grandmother did. Tell her hello for me.

You are correct...Mom never did. I'm sure my grandmother did to her children, but not to me; as a proper grandmother, her grandchildren ate whatever they wanted.

She asked me last week if you were still doing truck shows - she was disappointed this year's didn't happen, but of course understands why. I told her I was going to try to make the next one, she thought that was a good idea. I'll tell her you said hi.

[grumpin]

You are correct...Mom never did. I'm sure my grandmother did to her children, but not to me; as a proper grandmother, her grandchildren ate whatever they wanted.

She asked me last week if you were still doing truck shows - she was disappointed this year's didn't happen, but of course understands why. I told her I was going to try to make the next one, she thought that was a good idea. I'll tell her you said hi.

Good to hear, the tranny that is.

Getting some warmer weather for this time of year so maybe I’ll get the tranny serviced this week or next.