How and how much time does it take to get at the “pan” in a transmission to see if metal filings and such are there?
Fairly easy. Typical 4l60 trans. Drop pan, get a face full of oil, 1/2 hr of swearing. If your truck has no 3/4 that means clutch pak is shot and fluid will be black. If you have no reverse, you blew sun shell. Fluid will be clean. Would be nice if GM put the 4l80 in 1/2 ton trucks/blazers but they don’t.
what’s a 3/4? what’s a reverse?
“a 3/4” is 3rd and 4th gear operation i.e. direct and overdrive ratios. The 4L60 has a weakness in the 3/4 clutch pack. “a reverse” is Reverse ratio operation. When the ‘sun shell’ strips out, the transmission will be missing 2nd, 4th, and reverse ratios. Another weakness in the 4L60 design and a common failure.
You can help us help you by stating the symptoms the transmission is demonstrating that leads to the perceived need to check the pan for ‘metal filings’. BTW what has been the maintenence history on the transmission fluid, filter, and pan cleaning?
Hope to help.
He’s talking about potential problems because you’re saying you want to check for metal debris in the pan. If you suspect metal, there must be some reason you suspect it, right?
3/4 is the 3 to 4 shift.
Reverse is…reverse.
There are some good DIY posts w/pictures on the Trailvoy site.
How long it takes is highly dependent on your available tools and skills. I can have the pan off my TB in about 20 minutes from the time I park it.
Do you know at what RPM range the 3rd and 4th gear operate in? (After, I’ll reply on symptoms).
You should be in 3rd by 30 MPH with light throttle and 4th by 40 with light throttle. The RPMs will be around 2000 in both of these cases. The shift point and RPM will be higher the more the throttle is open. At Kickdown you may not even get 4th until 80-90.
Check with your factory service manual for exact shift specifications. Remember these are controlled by the Throttle Position Sensor and the Vehicle Speed Sensor.