Just wanted to post my experience in messing with lower, different fluid levels with the 3650 tranny. I got a copy of the TSB that applies to the 3650 owners complaining about gear clash/grind on the 1-2 and 2-3 shift especially when cold. Part of the TSB recommends using regular Mercon ATF fluid vs. the Mobil One Synthetic ATF and also lowering the fluid level from 4 quarts to around 3.1 quarts.
I drained and refilled my 3650 with 3.3 quarts of Motorcraft Mercon ATF (per TSB fluid specs/part #) and immediately the 1-2 shift seemed better/easier, but not by a large margin. Then, about 100 miles and one week later, I noticed the shift quality was getting worse on the 1-2 and seemed far worse on the 2-3. I immediately drained my tranny and refilled it with 4 quarts of Mobil 1 synthetic ATF and immediately noticed improved shift action. However, all this did was bring it back to the normal "cruddy" shift quality. I'm back to living with this and still accept the fact that this 3650 tremec, while notchy as heck, seems to be pretty bullett-proof (hasn't broken yet!
Another interesting note is that despite the fact that my car was completely level, 4 quarts of tranny fluid still left the fluid level below the fill hole - enough that it wasn't even close to spilling out. I should also mention that I do have Steeda lowering springs, which might slightly affect fill levels since I was on a drive-on lift but I can't imagine it would be that significant. I couldn't even feel the fluid with my fingers.
So, from my own personal experience, I would not recommend lowering your fluid level per that TSB for improved shift action. It just plain didn't work for me. I'm trying to focus on the fact that despite some serious abuse, this tranny is still holding up just fine. I guess I'll take that, although it would sure be nice if the tranny shifted well on top of being a sturdy piece of equipment.
It's definitely very frustrating when you get 10 different answers to this simple question - "what is the fill procedure with the 3650 tranny and what are the fluid specs?" Tremec and my Ford Manual says 4 quarts of Mobil One Synthetic; there's a TSB from Ford that says 3.1 quarts of Mercon non-synth. Based on my own personal experience, I'm sticking with Tremec and Ford's original specs.
I drained and refilled my 3650 with 3.3 quarts of Motorcraft Mercon ATF (per TSB fluid specs/part #) and immediately the 1-2 shift seemed better/easier, but not by a large margin. Then, about 100 miles and one week later, I noticed the shift quality was getting worse on the 1-2 and seemed far worse on the 2-3. I immediately drained my tranny and refilled it with 4 quarts of Mobil 1 synthetic ATF and immediately noticed improved shift action. However, all this did was bring it back to the normal "cruddy" shift quality. I'm back to living with this and still accept the fact that this 3650 tremec, while notchy as heck, seems to be pretty bullett-proof (hasn't broken yet!
Another interesting note is that despite the fact that my car was completely level, 4 quarts of tranny fluid still left the fluid level below the fill hole - enough that it wasn't even close to spilling out. I should also mention that I do have Steeda lowering springs, which might slightly affect fill levels since I was on a drive-on lift but I can't imagine it would be that significant. I couldn't even feel the fluid with my fingers.
So, from my own personal experience, I would not recommend lowering your fluid level per that TSB for improved shift action. It just plain didn't work for me. I'm trying to focus on the fact that despite some serious abuse, this tranny is still holding up just fine. I guess I'll take that, although it would sure be nice if the tranny shifted well on top of being a sturdy piece of equipment.
It's definitely very frustrating when you get 10 different answers to this simple question - "what is the fill procedure with the 3650 tranny and what are the fluid specs?" Tremec and my Ford Manual says 4 quarts of Mobil One Synthetic; there's a TSB from Ford that says 3.1 quarts of Mercon non-synth. Based on my own personal experience, I'm sticking with Tremec and Ford's original specs.