Okay so i have a 2005 GMC 2500 gasoline destroyer that has 190k on it now. Original trans is leaking and i happen to have a matching GM 4L80E Goodwrench trans new in the crate. Trans on the truck is fine other than the miles and leak. I've got a shop that will swap it for a good price. I can sell the still working 4L80E to someone looking to build a trans.
So, if you had a fresh 4L80E what fluid would you use? Dex VI? Something in the Dex III viscosity range? I'm tempted to spend the cash for Delvac 1 ATF. I don't tow heavy and this rig sees about 5k miles a year or less. Seems GM has back dated Dex VI for these units but some people say it doesn't work well while others praise it.
So, if you had a fresh 4L80E what fluid would you use? Dex VI? Something in the Dex III viscosity range? I'm tempted to spend the cash for Delvac 1 ATF. I don't tow heavy and this rig sees about 5k miles a year or less. Seems GM has back dated Dex VI for these units but some people say it doesn't work well while others praise it.