How to diagnose transmission clunking and slipping before replacing it
Clunking, grinding, or whining noises when shifting into gear—alongside delayed engagement—often indicate underlying transmission trouble rather than immediate failure. Without proper diagnostic tests to isolate the root cause, owners are left guessing whether the transmission actually needs a full replacement or if a smaller component is at fault.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Replacing the entire transmission
- 2Checking fluid level and color
- 3doing a drain and fill of transmission fluid to see if it prevents damage
- 4Consulting online forums for mechanical diagnosis
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“My clutch started to smoke and the transmission was ass. I just wanted to get Sure if its for Real the clutch or not”source ↗
“car is a mr2 sw21 and it started to smell 5 mins After driving and After trying to Speed up it didnt worked Well.”source ↗
“I have a 2014 Silverado, it’s been slipping for like 6 months in reverse.”source ↗
“When in auto it doesn’t slip at all and is fine but when shift to reverse or drive it makes a clunk followed by grindy whining noise for like 2 seconds then it’s fine.”source ↗
“This is my first 4wd project and I’m kinda lost on diagnosing. I’m pretty confident it the trans but before I replace it what tests could I do?”source ↗
“The car is starting but i have no transmission my Motor is Speisung up but my car stays still.”source ↗
“I have a 2010 Toyota Rav4 v6 automatic engine around 169,000 miles and the car feels pretty fine but I got confusing information about my transmission recently so I’m just hyper vigilant. And concerned! Is this something I should worry about? Is it too late?”source ↗
Where this came up
People with this problem also raised
- 58How to explain an intermittent car noise to a mechanic
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- 2Manual transmission still making noise after fluid top off
- 18Why are my brakes squeaking and shaking the floorboard?
- 31Why does my car make a loud rattle when starting the engine?
- 18Why does my car run terribly and stutter after a long drive?