Transmission filter change + info
Posted: Sun Mar 06, 2016 7:54 pm
Admin: Copied into the Technical reference library. Original thread is here: http://www.delica.ca/forum/viewtopic.php?f=6&t=17427
Lately I've noticed that if I apply too much power from a standstill, the gearshift from 1st to 2nd is a bit harsh. It's a classic symptom of a clogged filter mesh (the restriction causes low fluid pressure, the resultant sloppy shifts are most noticeable in the lower gears). I suspect I'm only noticing it recently because I've tuned the engine to make a wee bit more power than it used to. Living at the bottom of a steep hill probably doesn't help.
Time to replace the mesh filter. While taking pictures. But first, a bit of research into our Automatic gearboxes.
Mitsubishi call our transmission an V4AW2, but it's made by Aisin AW and fitted to a great many vehicles, not just Mitsubishis. Toyota call it an A44DL or an A45DL, depending on the clutch packs fitted. Dodge (and most of the internet forums) call it an AW372L. Aisin's ID plate calls it an AW03-72L. Some manufacturers (Volvo in particular) fit it with a proper paper filter as well as the mesh filter, but Mitsubishi and Toyota just fit the mesh.
Incidentally, the "L" in the Aisin model number means it has a lockup torque converter. Not all L300s had this. The best way to check is to look at your transmission's ID plate: ("91" is the year of manufacture, "D" means April (A=January and so on) and 65014 is the actual serial number.
Righto. On with the messy bit.
Drain the transmission fluid from the pan. Detach the dipstick tube- there's a single 12mm bolt near the top. The tube has an O-ring where it joins the pan, and it can be difficult to separate the two- it's much easier to do it from above, rather than from underneath while it's raining ATF on you. Remove the pan- take note of how loose the 10mm bolts are. They should be little more than hand tight (4.5Nm/3.3ft.lb). From the factory the transmission had a gasket, and if yours is still there it should come away cleanly and be re-usable. If it's been replaced with silicone gasket then you're going to have to gently cut the pan off. Unbolt the mesh filter from the underside of the transmission and replace with a new one. Again, note that the 8mm bolts holding it on are little more than hand tight (5.5Nm/4ft.lb). Take care when removing the screen- there's about a pint of ATF trapped above it, and it all falls down -sploosh!- when the screen comes off. I didn't take photos of this bit because it was raining transmission fluid under there, but here's the new screen and gasket before installation (and the old one with gunk visible on the mesh):
Next clean the pan and the two magnets, while being thankful there aren't any large metal shavings or gunge in there: Reinstallation is the reverse of removal, unless you've damaged the gasket, in which case you'll have to clean up the flange surfaces and use silicone gasket maker to seal the pan.
Reinstall the dipstick tube, and refill the transmission through it.
In my case, the old filter was more than half clogged- and with the new filter the gearshifts are back to normal. Phew!
Part numbers:
MD951626 Oil Pan Gasket
MD951878 Dipstick tube O-ring
MD609189 Filter
MB896471 Filter Gasket
Lately I've noticed that if I apply too much power from a standstill, the gearshift from 1st to 2nd is a bit harsh. It's a classic symptom of a clogged filter mesh (the restriction causes low fluid pressure, the resultant sloppy shifts are most noticeable in the lower gears). I suspect I'm only noticing it recently because I've tuned the engine to make a wee bit more power than it used to. Living at the bottom of a steep hill probably doesn't help.
Time to replace the mesh filter. While taking pictures. But first, a bit of research into our Automatic gearboxes.
Mitsubishi call our transmission an V4AW2, but it's made by Aisin AW and fitted to a great many vehicles, not just Mitsubishis. Toyota call it an A44DL or an A45DL, depending on the clutch packs fitted. Dodge (and most of the internet forums) call it an AW372L. Aisin's ID plate calls it an AW03-72L. Some manufacturers (Volvo in particular) fit it with a proper paper filter as well as the mesh filter, but Mitsubishi and Toyota just fit the mesh.
Incidentally, the "L" in the Aisin model number means it has a lockup torque converter. Not all L300s had this. The best way to check is to look at your transmission's ID plate: ("91" is the year of manufacture, "D" means April (A=January and so on) and 65014 is the actual serial number.
Righto. On with the messy bit.
Drain the transmission fluid from the pan. Detach the dipstick tube- there's a single 12mm bolt near the top. The tube has an O-ring where it joins the pan, and it can be difficult to separate the two- it's much easier to do it from above, rather than from underneath while it's raining ATF on you. Remove the pan- take note of how loose the 10mm bolts are. They should be little more than hand tight (4.5Nm/3.3ft.lb). From the factory the transmission had a gasket, and if yours is still there it should come away cleanly and be re-usable. If it's been replaced with silicone gasket then you're going to have to gently cut the pan off. Unbolt the mesh filter from the underside of the transmission and replace with a new one. Again, note that the 8mm bolts holding it on are little more than hand tight (5.5Nm/4ft.lb). Take care when removing the screen- there's about a pint of ATF trapped above it, and it all falls down -sploosh!- when the screen comes off. I didn't take photos of this bit because it was raining transmission fluid under there, but here's the new screen and gasket before installation (and the old one with gunk visible on the mesh):
Next clean the pan and the two magnets, while being thankful there aren't any large metal shavings or gunge in there: Reinstallation is the reverse of removal, unless you've damaged the gasket, in which case you'll have to clean up the flange surfaces and use silicone gasket maker to seal the pan.
Reinstall the dipstick tube, and refill the transmission through it.
In my case, the old filter was more than half clogged- and with the new filter the gearshifts are back to normal. Phew!
Part numbers:
MD951626 Oil Pan Gasket
MD951878 Dipstick tube O-ring
MD609189 Filter
MB896471 Filter Gasket