2005 Corolla Ce New Vibration On Upshifts After Tran Fluid Change

When my car is cold or even just cooled down for an hour there is a new vibrational sound just before upshift from 1st/2nd, 2nd/3rd, and 3rd/4th. If I keep speed I can draw that sound out til either upshift or slow down. I recently had an atf change at 210k by my mechanic of 20 years. He has done all the maintenance on car (5k oil/filter changes, brakes whenever needed, etc). This is the 2nd atf change he's done for me (the other at 100k and no complaint then). This change was premium, sucking most of the fluid out thru the top, replacing with top quality atf (but not Toyota's as I had specified 1st time but not this time).When I brought this to his attention he thought that it had more to do with mileage on trans, using new clean atf when it expected dirty state, and the wear and tear of tran's age. After seeing so many items about the Toyota atf specifications in these forums, no matter how high quality atf was used that it might not exactly match Toyota atf, and is that the cause of the vibration?

Find out what ATF he used. There are a couple different ways this could go. They do make "universal" fluids, but I'm not a fan of them - Toyota Type T-IV ATF has a specific viscosity and particular blend of friction modifiers to work with the transaxle. Unless the fluid specifically says - Toyota Type T-IV ATF compliant - don't use it. Some shops stock only one kind of ATF - to make it vehicle compatible - they add a friction modifier to the base ATF. This can have unexpected results - transaxle noise, slipping, overheating, etc. Even with a full flush, they can still have problems.

Top end flushes, where they siphon the old fluid out, is not the best way to do a flush on these cars. Better way is to connect to the transmission cooler lines, let the engine pump the fluid through, even better way is to use those flushing units that attached to the pump pickup. Those are more involved, have to remove the transmission pan and connect to the bottom - but it gives you a chance to clean any residue on the bottom of the pan and remove/replace the oil filter screen.

If the transaxle service is the cause of the vibration - that is hard to say. As there are a number of things that can cause the behavior that you are describing. But to put blame on the age and mileage, transaxle "expecting dirty oil" - that is completely unacceptable on his part. If the fluid is correct, should be no issue with the transaxle. With proper care and routine fluid maintenance and making sure the fluid never overheats, the transaxle should not have any issue. 200K miles over 8 years is nothing to this generation of Corolla's powertrain.

What is more likely to cause this would be the engine and transaxle mounts, serpentine belt tensioner, loose exhaust heatshield, or worn exhaust system donuts/gaskets. I wouldn't rule out the transaxle, but that is tough to diagnose. But since it sounds like you can reproduce it at a specific RPM (right before a shift, this generation has pretty even spacing between the gears)- I'd look into some resonance issue (something keyed to the RPM that is touching something on the chassis, transmitting the vibration.

Once again fishexpo101 thank you for your comprehensive and detailed reply. I'll be going up to my mechanic next week and will check out your suggestions and also get an obd readout. Will reply with results.

fishexpo101 - did not mean to malign my mechanic, i translated his talk (poorly) about possible vicosity etc factors being play with fluid change - he showed me the label on his trans fluid drum and it stated Toyota Type T-IV ATF compliant - he also agreed with your suggestion that it could be a resonance issue and we will try to check it (and your other suspects) out in another 2k miles when he does an oil change, coolant change, and plugs change (coolant and plugs which i already bought at toyota) and has the car up on the lift - will keep you posted - thanks again for your info and expertise - joe