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I have a convertible C8 and wanted to add the extra 2 quarts to the transmission. Following the YOUTUBE videos posted I removed the engine cover and back panel for access to the engine bay.
Problem 1: you cannot open the convertible top to the service position if the trunk is open. Not wanting to remove the trunk lid forces one to have either the engine bay open or the back open. You cannot have both.
Problem 2: After removing the bolts supporting the Airbox one finds that it is not possible to move the airbox back far enough to expose the brass fill plug from above like one can on the coupe. The shape of the convertible does not allow it. I really did not want to remove the airbox due to the problem of inaccessibility from the above mentioned problem.
Problem 3: One can get to the fill plug but the space is small (about 1 1/4 inches vertically and my 6mm allen wrench was rounding out the interior hex. Therefore, I put it all back together.
The other solution of tilting the car 13 degrees mentioned on another post worked perfectly. I have a lift so it was easy to remove the appropriate bottom panels (2) and get best access to the check fill level plug. (One does not have to remove those panels but you have much better visibility.
Thanks for the ideas people. Some of us just need help.
I went ahead and added the 2 extra DCT quarts earlier today using the tilt method.
I'm convinced that this is the fastest and easiest way to add the extra DCT fluid, given all the disassembly required to remove the airbox to access the upper DCT fill plug. At least four people who've posted their DCT fill experience have mentioned that they stripped the top DCT fill plug, which is made of brass. So I opted for the tilt method.
After loosening the driver's side rear wheel lug nuts, I jacked up the rear and removed the wheel. Here's a picture of the side DCT fill plug, which is easily accessible with a 17mm socket and extension, taken from the wheel well: I used two jacks (driver's side front and rear) with locking jacking pucks, and gradually lifted the drivers side uniformly. We've seen a 13 degree angle mentioned elsewhere - I lifted the car until the body clearance measured in front of the rear tire was increased from it's original 5.5" to 22". I set-up two jack stands after reaching this height. For the 74" width of the C8 at this point of the car, a 22" height from the floor corresponds to approximately 13 degrees. I used a funnel with an attached clear vinyl tube from a wood-chipper I own (which is used to fill the chipper motor oil), and it worked well. The tubing is 1/2"OD x 3/8" ID, and I cleaned the tubing by using a rifle cleaning rod and some microfiber patches. When adding the DCT fluid,I held the tubing in place in the DCT fill hole with my left hand while I poured the DCT fluid into the funnel using my right hand. It went pretty quickly, maybe 3 minutes for both quarts.
I did not drop the body pans, and I didn't want to accidentally drop the DCT side fill bolt (which would likely force me to then drop those two body pans), so after loosening the 17 mm bolt I placed a small piece of duct tape across the socket and bolt to keep the bolt attached to the socket as I extracted the socket and extension. After adding the DCT fluid, I used this same piece of duct tape to hold the bolt in the 17mm socket again, so that it didn't fall out of the socket as I threaded the bolt into it's hole. As for the torque of this bolt, which I haven't seen published anywhere, before removing it I used a Sharpie pen to mark the bolt and the DCT casting so that I could tighten it to the same position as before, allowing me to approximate the torque spec. The bolt has a nice O-ring, BTW.
After gradually lowering the car, front and rear, I put on the rear wheel and torqued the lug nuts to 140 ft-lb. I then took the car for a test drive.
There isn't any noticeable change in shifting behavior or smoothness. I would say there is a small perceptible change in the "damping" of the transmission during acceleration and deceleration, as well as a slight increase in noise and vibration from the DCT as it swirls the additional 2 quarts.
I'll report any other observations I have as I accumulate miles.
Yes. Much easier method for me. I got that pump from an auto supply store - went every quickly. I am saving the pump in a labelled bag for future fills. I suppose I could have dismantled the air box and removed it but... Can you imagine the charges from your local dealer? My dealer's service manager was honest and said he "didn't have any idea" how to do it (and he had the service manual on his computer opened.
Yes. Much easier method for me. I got that pump from an auto supply store - went every quickly. I am saving the pump in a labelled bag for future fills. I suppose I could have dismantled the air box and removed it but... Can you imagine the charges from your local dealer? My dealer's service manager was honest and said he "didn't have any idea" how to do it (and he had the service manual on his computer opened.
I'm going to use this method, seems WAY easier than taking half the car apart! I'll probably do it after the "free" 7,500 mile filter change.
I would break something. No need to add the extra tranny fluid if not tracking. With a HTC I definitely wouldn’t be tracking. Many tracks won’t let the C8 convertible on the track.
Mines a 2020. But it doesn't matter. You have to fool it in thinking the trunk is closed by sticking a screwdriver into the latch and letting it take it down. Then you can open the tonneau cover. Put some microfibre clothes in place and be ready to stop it just at the end. You only have a couple of mm before they can touch.
Can I talk about an oil change on this thread? I tried to find a c8 thread about oil changes but could not. I have some insight on this subject that I would like to share.
The oil change process is actually very easy and strait forth. The only problem is removing the oil filter. To my dismay mine was one of the few that happen to be over torqued and impossible to
get off with my selection of oil filter wrenches as it is recessed under the bottom shroud. After backing the Vette onto ramps and chocking the front wheels for safety, I drained the oil. I then could not get the filter off.
A 74mm 15 flute is the proper size
but the one I bought slipped and would not budge the filter. Tried other tricks I know to no avail. With no auto parts stores open, I finally lined the cap type of filter wrench with duct tape enough to where it was
tight enough to remove. Putting it back on and adding the proper oil is straight forth. Of course every one should know that on the dry sump the oil level is checked similar to an automatic transmission, that is to
say warm and running. There was some discussions about drain plug torque but I am old school and have done oil changes for over 50 years. If you don't know how to tighten a drain plug snuggly without stripping
the threads then maybe you should not be doing oil changes. But if you feel uncomfortable then buy a good inch pound torque wrench.
Also this paragraph below is from a GM tech page I found about the by-pass valves in the PF-64 Delco filter. I wanted to use original parts because of possible warranty issues with only 1600 miles on my Vette.
I will use the free oil change when its time for the DCT change. I wanted to dump the oil just to make me feel better.
For those of you that want to use a different filter read below. Hope this helps.The PF64 and PF63 (Fig. 20) filters are commonly confused as an ACDelco PF48 and/or PF48E filter because both oil filters have the same appearance and oil can size. However, these oil filters are not the same and have different internal bypass valve opening pressure specifications. The PF48/PF48E has a pressure specification of 15 PSI (100 kPa) while the PF64/PF63E has a pressure specification of 22 PSI (150 kPa).
Refer to the Electronic Parts Catalog (EPC) to determine the proper part numbers for a replacement oil filter. If an aftermarket filter is used, it must have an internal bypass valve opening pressure specification, element integrity, filtration performance, media particle trap specification and burst strength that is equivalent to the original production oil filter.
Brocker
Do you have other pictures available? I will receive my C8 HTC late this month and I intend to add the 2 liters into the DTC.
I was wondering what was the best way to do this on a HTC but based on your experience I will follow your method.
Do you need to remove the rear wheel to get get to the check plug or you get to the plug by going under the car?
How many inches have you raised the car to reach the 13 degrees angle?
Have you been using 1 or 2 floor jacks (one in the front and one in the back)?
To remove the check plug, do we need a hex or a torx socket? Which size?
Thanks in advance.
Brocker
Do you have other pictures available? I will receive my C8 HTC late this month and I intend to add the 2 liters into the DTC.
I was wondering what was the best way to do this on a HTC but based on your experience I will follow your method.
Do you need to remove the rear wheel to get get to the check plug or you get to the plug by going under the car?
How many inches have you raised the car to reach the 13 degrees angle?
Have you been using 1 or 2 floor jacks (one in the front and one in the back)?
To remove the check plug, do we need a hex or a torx socket? Which size?
Thanks in advance.
To get a 13° angle, the lift would be about 15" (the track width is about 65"). 65"x tan(13°) = ~ 15".
I am going to use a Fumoto F105N M20 1.5 drain valve with an additional 1mm thick M20 nylon washer and pump the fluid in as this fellow is did in the link. (the 1mm thick washer allows the valve to orient pointing in a better direction than what shows in the link). https://www.midenginecorvetteforum.c...id-easiest-way
I am going to use a Fumoto F105N M20 1.5 drain valve with an additional 1mm thick M20 nylon washer and pump the fluid in as this fellow is did in the link. (the 1mm thick washer allows the valve to orient pointing in a better direction than what shows in the link). https://www.midenginecorvetteforum.c...id-easiest-way
Just ran across this. I have no idea what the risk really is, but thought it worth posting so people have the information when deciding what to do. Team ZR1 has provided a wealth of valuable information in the past:
Cyberspace Corvette forums breeds dummies at times and right now it has convinced C8 owners in flushing, draining and filling the DCT fluid by replacing the DCT drain plug at bottom of DCT with a shutoff valve replacing the plug and adding a hose to it
So problem is to use that for filling the DCT fluid has to be put in a container that air-pressure can be added and then back force the fluid into the DCT
Dummies did not think as the DCT has an expensive fluid filter as seen below and it will be directly in the path of that fluid under pressure forced to back flush the filter and push the trapped crap in filter back into the tranny.
Also depending on how much air-pressure they use could damage the paper filter and would not be known the DCT is then functioning without a functional filter and worse if made of paper could rip up and carried throughout the fluid around the DCT
Filter at this time is not cheap and not easy to buy one for around $200. Also a good chance if a cheap shutoff valve is used that the handle for open/close of valve pops open and drains all the fluid out without owner even knowing it until the DCT craps out.
Time instead should be to take the engine aircleaner setup out one time and add a hose to a coupler to replace the top fill plug with a fill hose connected to that and have hose long engine to end within engine bay so in future simply take a hose cap off, add a funnel and fill without having the jack the C8 up
Just ran across this. I have no idea what the risk really is, but thought it worth posting so people have the information when deciding what to do. Team ZR1 has provided a wealth of valuable information in the past:
Team ZR1 and repliers to their post talk of using 125 psi! One comment I read elsewhere indicated 10 psi works fine.
If one is concerned of ripping the paper in the filter, the metallic/magnetic filter made by Dodson sold by Cicio would take care of that worry.
To get a 13° angle, the lift would be about 15" (the track width is about 65"). 65"x tan(13°) = ~ 15".
I am going to use a Fumoto F105N M20 1.5 drain valve with an additional 1mm thick M20 nylon washer and pump the fluid in as this fellow is did in the link. (the 1mm thick washer allows the valve to orient pointing in a better direction than what shows in the link). https://www.midenginecorvetteforum.c...id-easiest-way
As you jack up the driver's side rear corner, the rear wheel suspension will unload and the wheel will move down about 3 inches (my C8 measurement) before the tire comes off the ground so using the wheel height @ 15 inches doesn't seem right to hit 13 degrees.
I think a better way to get an accurate height corresponding to a 13 degree tilt is to measure the height of the car just ahead of the rear driver's side tire.
The width of the car just ahead of the rear tires is about 74 inches, and the starting height at this point of the stock C8 is about 5.5 inches.
74 tan (13) = 17.1 inches, and you'll also need to add the initial 5.5 inch height (since you'll be measuring total height from the floor). So, the final height at the driver's corner just ahead of the rear tire will be a little over 22.5" to achieve a 13 degree tilt.
If the original poster was measuring the 15 inch height as the height of the tire off the ground (at the center of the tire's width), the car's tilt angle was above 13 degrees, given the suspension travel (~3 inches) of the rear wheel/tire. By my math he'd have been at around 16 degrees.
Anyhow, does anyone know how the magic value of 13 degrees was determined? It seems like you'd need to know the internal geometry (open volume) of the DCT to calculate that angle.
I went ahead and added the 2 extra DCT quarts earlier today using the tilt method.
I'm convinced that this is the fastest and easiest way to add the extra DCT fluid, given all the disassembly required to remove the airbox to access the upper DCT fill plug. At least four people who've posted their DCT fill experience have mentioned that they stripped the top DCT fill plug, which is made of brass. So I opted for the tilt method.
After loosening the driver's side rear wheel lug nuts, I jacked up the rear and removed the wheel. Here's a picture of the side DCT fill plug, which is easily accessible with a 17mm socket and extension, taken from the wheel well: I used two jacks (driver's side front and rear) with locking jacking pucks, and gradually lifted the drivers side uniformly. We've seen a 13 degree angle mentioned elsewhere - I lifted the car until the body clearance measured in front of the rear tire was increased from it's original 5.5" to 22". I set-up two jack stands after reaching this height. For the 74" width of the C8 at this point of the car, a 22" height from the floor corresponds to approximately 13 degrees. I used a funnel with an attached clear vinyl tube from a wood-chipper I own (which is used to fill the chipper motor oil), and it worked well. The tubing is 1/2"OD x 3/8" ID, and I cleaned the tubing by using a rifle cleaning rod and some microfiber patches. When adding the DCT fluid,I held the tubing in place in the DCT fill hole with my left hand while I poured the DCT fluid into the funnel using my right hand. It went pretty quickly, maybe 3 minutes for both quarts.
I did not drop the body pans, and I didn't want to accidentally drop the DCT side fill bolt (which would likely force me to then drop those two body pans), so after loosening the 17 mm bolt I placed a small piece of duct tape across the socket and bolt to keep the bolt attached to the socket as I extracted the socket and extension. After adding the DCT fluid, I used this same piece of duct tape to hold the bolt in the 17mm socket again, so that it didn't fall out of the socket as I threaded the bolt into it's hole. As for the torque of this bolt, which I haven't seen published anywhere, before removing it I used a Sharpie pen to mark the bolt and the DCT casting so that I could tighten it to the same position as before, allowing me to approximate the torque spec. The bolt has a nice O-ring, BTW.
After gradually lowering the car, front and rear, I put on the rear wheel and torqued the lug nuts to 140 ft-lb. I then took the car for a test drive.
There isn't any noticeable change in shifting behavior or smoothness. I would say there is a small perceptible change in the "damping" of the transmission during acceleration and deceleration, as well as a slight increase in noise and vibration from the DCT as it swirls the additional 2 quarts.
I'll report any other observations I have as I accumulate miles.
Mobius,
This is a very clear explanation of your work. .
I am planning to do the same procedure as soon as my car will hit the 500 miles break-in period.
Well done
So by tilting the car that much, wouldn't you be worried about damaging the passenger side wheels/tires? They would literally be sitting on the outer edge of the rim/tire combination.
HTC Transmission Fluid
