Did a 1x3 drain and fill with the redline type f automatic transmission fluid in my 05 TL and immediately started to get shudder in third gear. It seems to drive fine in auto mode but putting it into ss manual shift and letting it lock the torque converter in third gear under medium light throttle it starts to shudder and it is very noticeable. Hasn’t done it in other gears. Trans fluid level is right in the middle of the two holes on the dip stick so its not a lack of fluid. I’m planning on picking up some DW-1 and doing another drain and fill to see if that’ll take care of the issue but I figured I’d make a post here and maybe get some answers since I haven’t been able to find a thread on this specific issue.

Reason I’m thinking of doing a 1x3 with DW1 is because I’m assuming that the torque converter maybe isn’t getting enough fluid since type f atf has less friction modifiers than DW1. I don’t really think that’s the issue but I don’t know what it could be since most of the posts here state a 65% mix of type f does wonders for the transmission in durability of the clutch packs and shifts quiality.

 

So you filled it completely with Redline ATF or 65% blend with OEM Fluid?

On the safe side, I'd recommend draining the Redline and do a 3x3 of OEM DW1 Fluid. If the problem is gone, stick with OEM Fluid.

 

No, original fluid with one drain and fill of type f. I believe that’d put it at 39%.

 

If any one ever has a similar problem in the future doing a 1x3 drain and fill with DW1 seems to have fixed the issue completely as far as I can tell. Will do another drain and fill in a week or two to lower the percentage of type f even more.