Replacing the transmission filter on a Cadillac Catera
A friend has a 1997 Cadillac Catera that he really enjoys driving despite its unreliable service history. Recently the car refused to move indicating a transmission problem. He son had suggested trying a filter and fluid swap first and had planned to do the work in his driveway. However, he soon found that the Catera’s 4L30E transmission is a strange animal. It does not have a dipstick to check the fluid or even an easy way to add fluid.
The fluid is checked and added through a hole in the side of the transmission pan. The car has to be level and the engine running to check the fluid. To make matters worse, the exhaust pipe passes just inches away from the filler plug. He decided to let me do the job on my lift.
I began by lifting the car and removing the plug in the side of the pan. Fluid gushed out indication that the level is higher with the engine off than when it is running. I realized it was going to be a challenge to refill it when I was done.
I then dropped the pan by removing the 10mm headed bolts. The pan separated easily and cleanly. I poured the remaining fluid into the oil catch can. The fluid did not smell burnt or look too dark.
I noticed right away however that the magnet in the pan was thick with metal particles. I took a cell phone photo and sent it to the owner. I then cleaned up the magnet and pan.
The filter is held in place by three long bolts that surprised me by having ½ inch heads rather than the 13mm I was expecting. Wikipedia says the transmission for these cars is built in France.
There were more metal flakes on top of the filter making me think the transmission is heavily damaged. However we decided to button it back up with the new filter and fluid just to see.
I tried using a long tube and a funnel but filling by gravity just took too long. I rigged up a pump using a pressure bottle and a tube attached to it. This sped up transferring the fluid greatly. It still took me an hour an a half to get all the fluid in. I had to climb a ladder to start the engine once the fluid filled the pan with it off. I was able to get all the fluid in before the exhaust got too hot.
I dropped it down and took it for a test drive. I noticed right away that the jerky motion it had when first changing directions was gone. The car now started off smoothly just like a Cadillac should. I took it out on the road and it shifted smoothly through all its gears. I was really surprised that just changing the filter cured it.
I still need to recheck the fluid level now that it has had a chance to circulate the fluid, but it looks like it will be able to go a few more miles. I told him to start shopping for a transmission just in case.
[phpbay]catera transmission, 10[/phpbay]