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NBS Tahoe, Built 4l65e acting weird in cold weather
Long story short, I have a built 4l65e in my tahoe. 3000TT Yank, 5 pinion planetaries, 3/4 clutch upgrade, shift kit etc. BlackBear tuned for the trans.
The problem is it holds shift points and TC lockup when its really cold out. It has always done it since ive had it built, but it would go away after about a minute of driving and TC lockup at 45 did not take as long as it does this winter. This winter it really hangs onto 2nd gear and keeps the TC unlocked for about twice as long, as i make the same drive i have made every winter and I can time it out. I dont mind it, since it helps warm the truck up faster on the way to work, but I just want to make sure its not a problem waiting to happen. Once the trans warms up a bit, it shifts perfect and lockup happens at 45 every time like it should, never kicks out going up hills or anything. Just when its cold in the morning (-5 to 35 it seems) it does it. I am probably due for a fluid and filter change, its been 3 years since the trans got put in and prolly 35k miles, so that may have something to do with it. Any insight would be great, thanks guys. Just wanna make sure its nothing serious. |
It's normal. The idea is that it gets the fluid up to a temperature where it's not like goo. When the required temp is hit (I think it's 70 degrees?) the lockup functions normally.
Ah, found it. From the horse's mouth: Bulletin No.: 01-07-30-031A Date: February 25, 2004 INFORMATION Subject: 1-2, 2-3, 3-4, 4-5 Shift and Torque Converter Clutch (TCC) Characteristics During Cold Weather Operation on 4L60-E, 4L80-E or Allison Transmissions Vehicles Equipped with 4L60-E or 4L80-E Transmissions 1-2 Upshift If the throttle position (TP) is less than 37 percent, the 1-2 upshift will take place at a minimum speed of 19 km/h (12 mph). 2-3 Upshift ^ (2001 Model Year) If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 51 km/h (32 mph). ^ (2002-2004 Model Year) If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 43 km/h (27 mph). ^ If the throttle position (TP) is above 37 percent, the shifts will follow the normal shift pattern. 3-4 Upshift ^ (2001 Model Year) If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 75 km/h (47 mph). ^ (2002-2004 Model Year) If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 64 km/h (40 mph). ^ If the throttle position (TP) is above 37 percent, the shifts will follow the normal shift pattern. TCC Operation If the transmission fluid temperature is less than 17°C (62.6°F), torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 20°C (68°F). (2001 Model Year) When the engine coolant temperature (ECT) reaches 77°C (171°F), 2-3 and 3-4 upshifts will follow the normal shift patterns. A brief description of operation may also be included in the Owner's Manual. (2002 Model Year) When the ECT reaches 80°C (176°F), 2-3 and 3-4 upshifts will follow the normal shift patterns. A brief description of operation may also be included in the Owner's Manual. |
thanks man, i figured it was fine but just wanted to check. Just kinda weird that all of the sudden this winter it seems to be more noticeable than before, but that could just be me
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