Grit\Sand substance on Transmission Dip Stick

Morenar · October 25, 2019

Hello all,

I decided to check my transmission fluid today on my 2017 Sierra and when I pulled out the dip stick there was a dark sandy substance towards the bottom of the stick. I cleaned the dip stick, put back in and could notice that when I was sliding it back in I could hear it scrapping something grainy. I pulled the dip stick back out and check and still saw some of the sandy substance. The fluid did have a dark color to it. Keep in mind I just had the transmission repaired\rebuilt when the truck was under 10,000 miles. Supposedly a incorrect assembly at the factory. Now I am at 21,000 miles and seeing this has me concerned. See the pics below of the paper towel.

Lsgun1 · October 25, 2019

That fluid only has 11k on it? Holy crap. I'd get that flushed.

Morenar · October 25, 2019

Yep, I had already brought up my concerns with a weird sound when shifting into reverse gear a few weeks back when I took it in for the brake booster TSB. They said the checked the same function on another Sierra on the lot and it had the same noise. So I left it at that. Already made a follow up appt for Monday morning to bring it in for a look.

What ticks me off is if I bring it in for a transmission concern, you would think they would at least check the fluid.

Edited October 25, 2019 by Morenar

Lsgun1 · October 25, 2019

The black bits look like torque converter junk, coffee grounds is the best description.

dieselfan1 · October 26, 2019

That fluid should be nice and clean still.

Go to a different dealer

Morenar · October 28, 2019

On 10/25/2019 at 11:03 PM, dieselfan1 said:

That fluid should be nice and clean still.

Go to a different dealer

Just dropped it off. The same SA that told me last time the noise I was hearing was normal checked me in. I express my frustration and showed him the pictures. He has the nerve to tell me that the transmission fluid color will change over time. I said I understand but not at 11,000 miles after the last fluid change. The fluid smells and it had the debris in it. I showed him the pictures and he was like well yeah it should not be that dark. Duh!!

So waiting to see what they find. If I don't like what they say, I will take it to another dealer.

Bob2C · October 28, 2019

Just dropped it off. The same SA that told me last time the noise I was hearing was normal checked me in. I express my frustration and showed him the pictures. He has the nerve to tell me that the transmission fluid color will change over time. I said I understand but not at 11,000 miles after the last fluid change. The fluid smells and it had the debris in it. I showed him the pictures and he was like well yeah it should not be that dark. Duh!!
So waiting to see what they find. If I don't like what they say, I will take it to another dealer.

You have a lot more patience than me. I would have got back in my truck, found something heavy to tow up a mountain and run it until the trans blew. Then walk in with a smile [emoji3] and [emoji112] “ I”m back”.

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Morenar · October 29, 2019

Finally got a call from the service dept late yesterday afternoon right before closing. The SA tells me yes there is a problem and the master tech they used for transmissions was not able to get to my car to drop the pan and start to diagnose. This is one of two master technicians they have as the other was on vacation. They said they would get started on it today. They set me up with a blacked out 2020 GMC Yukon loaner this morning, which is a pretty nice ride. So now it's a waiting game to see what is actually wrong.

Morenar · November 8, 2019

Sorry for not updating sooner. Finally got the truck back on Tuesday after the dealership having it for almost a week and a half. So they had two master techs look at it during that time. One said the grit on the dipstick is rust from the dispstick tube itself and he then went to the lot and showed the same issue in other trucks to the second tech. The second tech said no, there's an issue as the fluid should not be that dark. Well finally they dropped the pan and found no shavings, transmission looks good, fluid was a bit dark. They decided to flush the fluid and then the second tech tested the transmission fluid thermal bypass valve and saw that it was failing. I had been commenting to the SA since I bought the truck that the transmission temp was getting up to 230F sometimes and he kept asking, are you getting an alert? I said no, then he said that's fine there is no issue. I would always tell him anything above 200F is going to cause fluid and transmission issues.

Well they ended up replacing the thermal bypass valve and flush the fluid. I can now see the transmission temp gets to around 200F-203F and then starts to drop to around 194F-198F. Something I was not seeing before. This is the fourth time I had to bring it in for transmission issues. Not sure what to expect next.

Edited November 8, 2019 by Morenar

Doublebase · November 10, 2019

I got to admit, I checked my fluid just last week and I too noticed a "dust" on the white paper towel I used to check the fluid. Immediately I was concerned...but then I started thinking...ok, I'm, using a clean white paper towel...would I have even seen this if I was using a shop rag? Probably not...so maybe this is normal? With me it wasn't so much the fluid, as the dipstick itself...it had some dust on it. The fluid looked fine, it smelt fine, I didn't see any particles in it. Nothing. So I wiped the dipstick off and checked it again...and there wasn't any dust on it. My truck is a 2018 with 41,000 miles.

I did a drain and fill at 20,000 miles. I'll be doing a pan drop next week...change the filter, check out the magnet (I'm more curios than anything). I'm starting to get some harsh downshifts, I'm getting a little bit of a shutter when going up hills on the highway at lower speeds. The thing seems to be shifting all of the time. So yeah I'm starting to have some concerns. I don't have high temp situations where I live; in fact the only time this tranny gets above 190 is on the rare occasion which I'm driving on the highway in 100 degree heat (which I've only done once), otherwise this thing is usually operating between 170-180.

I'll report back after I drop my pan and see what/what isn't in that pan. Otherwise it's been a great truck and in all honesty the weird shifts are something I can live with...tranny failure, not so much.

Morenar · November 11, 2019

Latest update. So after a few days of running the truck around town and highway, the transmission temps are now rising up to 232 without cooling down. Before the thermal bypass valve replacement, it would hit around 230F but not as often as I have seen it in the past few days. Even with the ambient temps being in the 60's. It seemed liked the issue with at least the high temp was resolved but I guess not. Owner's Manual states normal operating temperature is 180F-200F. I have had nothing but transmission issues and other parts going bad (gas pedal failure, condenser failure) for the past year of the two year period I have owned the car. I am starting the lemon law process. My time is short before my 24 month deadline is up for the reporting of the Lemon Law. I am not confident that years down the road there will not be a failure that's going to be really expensive.

Edited November 11, 2019 by Morenar

Doublebase · November 11, 2019

11 hours ago, Morenar said:

Latest update. So after a few days of running the truck around town and highway, the transmission temps are now rising up to 232 without cooling down. Before the thermal bypass valve replacement, it would hit around 230F but not as often as I have seen it in the past few days. Even with the ambient temps being in the 60's. It seemed liked the issue with at least the high temp was resolved but I guess not. Owner's Manual states normal operating temperature is 180F-200F. I have had nothing but transmission issues and other parts going bad (gas pedal failure, condenser failure) for the past year of the two year period I have owned the car. I am starting the lemon law process. My time is short before my 24 month deadline is up for the reporting of the Lemon Law. I am not confident that years down the road there will not be a failure that's going to be really expensive.

That's terrible and you absolutely should not be reaching transmission temperatures of 230 when it's 60 degrees outside. Wow.

Morenar · January 9, 2020

Hello all,

I thought it was time to update everyone on what has happen since the last post. I proceeded with my Lemon Law claim with the BBB autoline, as that is the first step here in Florida. Long story short, I had my arbitration hearing on Friday 01/03 with the BBB and GM. I presented all my evidence of my transmission issues since owning the vehicle and at the last minute GM decided to enter into evidence document 2654690 (DTC P0711-P0713) see attached. Where they state that the temperatures my Sierra is hitting are well within normal range, even though the owners manual states normal operating transmission fluid temperature is 180F - 200F. In this document it states that if the fluid were to detect a high temperature which they say can be upwards to 345F it would have alerted with a warning light. Because I have not seen the warning lights come up, this pretty much supports GM's claim that the vehicle is working as expected. Even though my temps are hitting 246F so far.

Of course the BBB denied my claim on 01/06, which I rejected and now I am preparing to file to the Florida Attorney Generals Office.

I knew this wasn't going to be easy.

doc 2654690.pdf