Thicker or thinner fluid?
The **** that came out of my boys car was thin as **** and when you rubbed it between your fingers it just felt wrong, not like trans fluid, lost it's lubricity and probably it's hydraulic properties because it was so thin.
I meant thicker... AIUI, as transmission fluid ages it gets thicker and less slippery...
Unfortunately haven't found any engineering references that describe trans fluid viscosity as it ages but the following site does state the following:
Color of Transmission Fluid
Red Transparent
What It Means: This is what new or like new transmission fluid should look like. Keep your fluid in this condition and make sure it doesn’t get low and you will likely never have a serious transmission problem.
Recommended Action: Check the fluid condition regularly and follow the manufacturer’s transmission/transaxle service procedures and service intervals.
Light Brown Semi-Transparent
What It Means: Your transmission fluid is in generally good condition. Maintain this fluid condition and watch for leaks and your transmission will probably outlast the rest of your vehicle.
Recommended Action: Check the fluid condition regularly and follow the manufacturer’s transmission/transaxle service procedures and service intervals.
Dark Brown Opaque
What It Means: Your transmission fluid is old, dirty, and contaminated and doesn’t provide adequate lubrication. Poor lubrication causes excessive wear and damage to internal parts. Dark brown transmission fluid also increases heat inside the transmission, which can quickly lead to transmission failure.
Recommended Action: Take action now before this fluid condition causes serious problems or even transmission failure. Perform a transmission fluid and filter change or a complete flush of the transmission.
Very Dark Brown or Black
What It Means: The transmission fluid is old, dirty, contaminated, and/or oxidized. A burnt odor will confirm oxidization.
Recommended Action: Take action immediately. Some internal damage may have already occurred. If your transmission is still working properly, a fluid and filter change or flush should be performed immediately. If problems already exist, a transmission rebuild may be necessary.
Light Pink
What It Means: When water or coolant has entered the transmission, the friction clutches fall apart and seals are ruined. The water enters the transmission through a damaged or leaking transmission oil cooler line radiator. Complete failure of the transmission is almost certain.
Recommended Action: Unfortunately, you will need to rebuild or replace your transmission.
Fluid Smell
Smell the fluid. If it has a burnt odor, the transmission has overheated and the fluid is oxidized. The result is poor lubrication, increased friction, increased heat and excessive wear or damage to internal parts and seals. In most instances, burnt smelling transmission fluid means some internal damage has already occurred.
Blotter Test
Place a couple of drops of the ATF on a paper towel and wait about 30-seconds or so. If the fluid has spread out and is red or light brown in color, the fluid is good – No action is needed. If the fluid does not spread out and is dark in color, the fluid is oxidized. In this case, a fluid and filter change or flush is needed.
The color of the automatic transmission fluid can help diagnose transmission problems and indicate health of your transmission. Here are 5 colors of ATF and what each means...
cartreatments.com
PS: I'd think a more viscous (thick) fluid would not spread out as much as a less viscous (thinner) fluid if dropped on blotting paper...
PPS: No idea why your boys old trans fluid was thinner coming out than the new stuff going in. If its noa a one owner maybe the previous chap put the wrong stuff in the trans or maybe trans fluid does get thinner... As ive said, I've not pulled appart an auto tnsmission so I'm no expert. I have however changed trans fluid but never really old trans fluid...
