Checking transmission fluid

[Daves88gmc]

This is a dumb question but when checking the transmission fluid on my 88 GMC 700r4 with the engine running and up to temp should the transmission fluid be heavily coating the dipstick?

If you check the fluid before the truck is started the fluid is really thick on the dipstick but checking with the engine hot and running it comes up to the hot mark consistently but it seems like it's lightly coating the dipstick. My transmission isn't acting weird but I'm worried I'm misreading and thinking it's full when it's not.

Thanks.

 

[SkyHighColorado]

this is normal, not a dumb question. The oil is just thinner and flows easier when its at running temp. Make sure you have it on a level surface and run the shifter from park through 1st and back to park so a couple times so the fluid can get everywhere it needs to then put it back in park and check it. It should be in the hot range on the dipstick if you have been driving it around.

 

[Daves88gmc]

Thanks that is good to hear. I usually check it after I drive about 15 miles to work since it's on level ground there and I know everything is up to temp. It's always shown up near the top of the hot markings. Fluid is also red and doesn't have any odd smells so everything is good there. I should probably change it soon though it's been about 30,000 miles since I changed the fluid and filter last. I haven't ran it thru the gears before checking it though so I'll recheck it that way.

Thanks.

 

[Birchyboy]

This is something I struggled with when I upgraded my transmission cooler. I didn't have the foresight to somehow capture the fluid that drained when I removed the old one, so I had no idea how much to add back in. Couple that with the increased capacity of the new cooler, and I struggled with adding the right amount back in. Too little at first could toast the thing on a drive, and too much is just as bad. I wish it was easier to check the level.

 

[SkyHighColorado]

yep. sound like its doing just fine. 30,000k is about where I try to drop the pan and change the filter. I recently put on a B&M pan that has a drain plug so I might do it at about 20k and then drop the pan after another 20k and change the filter.