4m40 Transmission "growl" on throttle increase in 4th gear
Posted: Tue May 11, 2021 2:20 pm
I recently acquired a lovely van (Series 2 L400 Diesel) in excellent condition with ~135,000 km's. Shortly after receipt of the van I noticed an intermittent sound, only during throttle increase when the van already has forward momentum, i.e. if I'm already rolling in 4th gear, and I relax on the throttle, the sound comes for a moment when i give it some throttle again. The sound is usually in the 1.5 to 2k revs range and seems to be louder when the engine/transmission are warmer. I'm also pretty sure it only happens when the transmission is in OD/4th gear. It has a similar sound to a distant semi-truck using engine brakes, if that makes sense!
I'm a marine engineer but a total newbie when it comes to automotive engines, and I haven't yet had time to study any literature on how the power gets transmitted from the engine to the wheels. At first I suspected something related to the engine itself, but I think I've ruled that out since I'm unable to re-create the sound with the van in neutral.
I suspect there's some sort of excess backlash or loose gear somewhere in the connection between the engine and transmission. The transmission fluid appears to be in great shape, even after 5000+ km's of driving with this sound happening, though I haven't opened the drain plug on the bottom, I've simply looked at the fluid on the dipstick itself. This being my first Delica, I don't have a feel to compare whether this one in particular lacks power, but as far as I can tell it works and feels fine.
It's due for it's first servicing at CCA, so I'll be taking it in as soon as I get out of jail (the ship I work on ) in June and let them know my symptoms.
Hoping somebody here has some insight on this noise so I can get a better picture of what might be going on!
Much appreciated Delica fam.
-Rhino
I'm a marine engineer but a total newbie when it comes to automotive engines, and I haven't yet had time to study any literature on how the power gets transmitted from the engine to the wheels. At first I suspected something related to the engine itself, but I think I've ruled that out since I'm unable to re-create the sound with the van in neutral.
I suspect there's some sort of excess backlash or loose gear somewhere in the connection between the engine and transmission. The transmission fluid appears to be in great shape, even after 5000+ km's of driving with this sound happening, though I haven't opened the drain plug on the bottom, I've simply looked at the fluid on the dipstick itself. This being my first Delica, I don't have a feel to compare whether this one in particular lacks power, but as far as I can tell it works and feels fine.
It's due for it's first servicing at CCA, so I'll be taking it in as soon as I get out of jail (the ship I work on ) in June and let them know my symptoms.
Hoping somebody here has some insight on this noise so I can get a better picture of what might be going on!
Much appreciated Delica fam.
-Rhino