99 ECSB W/4L80 shifting.... weird... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DjS71 · 01-12-2012, 12:52 PM

Got a '99 2500 ESCB with 6.0/4L80E w/70K

The last month or so, i've notived that, especially when its cold, it hangs out in gear longer then it used to. Maybe just time for a filter change? (no lift = nightmare!) What do you guys think?

clinebarger · 01-12-2012, 07:10 PM

Sounds normal...........

2-3, 3-4 Shift Characteristics During Cold Weather Operation on 4L60-E or 4L80-E Transmission

Transmission operation during cold weather has been revised on these vehicles to provide faster engine warm-up and improved heater performance. During initial key-up, if intake air temperature (IAT) is less than 32°F, 2-3 and 3-4 upshift speeds will be affected as detailed below.

2-3 Upshift

^ If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 32 mph.

^ If the TP is above 37 percent, the shifts will divert back to the normal shift pattern.

3-4 Upshift

^ If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 47 mph.

^ If the TP is above 37 percent, the shifts will divert back to the normal shift pattern.

TCC Operation
If the transmission fluid temperature is less than 62.6°F, torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 68°F.

When the engine coolant temperature (ECT) reaches 171 °F, 2-3 and 3-4 upshifts will divert back to the normal shift patterns.

If you getting a harsh 1-2 shift............There is a different PCM calibration for 99 models that deal with this specific problem..........

DjS71 · 01-12-2012, 08:37 PM

Wow, thats way more than i expected. Also, its awesome. Thank you.

Justin87 · 01-13-2012, 02:33 AM

Wow! I never knew about that. Great info Clinebarger!

67ChevyRedneck · 01-13-2012, 08:42 AM

Yup, I bought my truck used in 2005 and I thought there was something wrong with it too (TC wouldn't lock on interstate) the first winter I owned it. This morning was really the first cold morning I've run the truck and it was doing the same as described above, holding onto shifts longer.

01-12-2012, 12:52 PM	#1
DjS71 Registered User Join Date: Feb 2009 Location: Santa Rosa, CA Posts: 267	99 ECSB W/4L80 shifting.... weird... Got a '99 2500 ESCB with 6.0/4L80E w/70K The last month or so, i've notived that, especially when its cold, it hangs out in gear longer then it used to. Maybe just time for a filter change? (no lift = nightmare!) What do you guys think? __________________ 1971 C10 Short/Fleet 307-2BBL/3OTT 1999 Silverado 2500 ECSB 6.0/4L80

01-12-2012, 07:10 PM	#2
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: 99 ECSB W/4L80 shifting.... weird... Sounds normal........... 2-3, 3-4 Shift Characteristics During Cold Weather Operation on 4L60-E or 4L80-E Transmission Transmission operation during cold weather has been revised on these vehicles to provide faster engine warm-up and improved heater performance. During initial key-up, if intake air temperature (IAT) is less than 32°F, 2-3 and 3-4 upshift speeds will be affected as detailed below. 2-3 Upshift ^ If the throttle position (TP) is less than 37 percent, the 2-3 upshift will take place at a minimum speed of 32 mph. ^ If the TP is above 37 percent, the shifts will divert back to the normal shift pattern. 3-4 Upshift ^ If the throttle position (TP) is less than 37 percent, the 3-4 upshift will take place at a minimum speed of 47 mph. ^ If the TP is above 37 percent, the shifts will divert back to the normal shift pattern. TCC Operation If the transmission fluid temperature is less than 62.6°F, torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 68°F. When the engine coolant temperature (ECT) reaches 171 °F, 2-3 and 3-4 upshifts will divert back to the normal shift patterns. If you getting a harsh 1-2 shift............There is a different PCM calibration for 99 models that deal with this specific problem.......... Attached Images

01-12-2012, 08:37 PM	#3
DjS71 Registered User Join Date: Feb 2009 Location: Santa Rosa, CA Posts: 267	Re: 99 ECSB W/4L80 shifting.... weird... Wow, thats way more than i expected. Also, its awesome. Thank you. __________________ 1971 C10 Short/Fleet 307-2BBL/3OTT 1999 Silverado 2500 ECSB 6.0/4L80

01-13-2012, 02:33 AM	#4
Justin87 Registered User Join Date: Jun 2009 Location: Lawson Mo Posts: 147	Re: 99 ECSB W/4L80 shifting.... weird... Wow! I never knew about that. Great info Clinebarger! __________________ 2006 Silverado 2500 HD

01-13-2012, 08:42 AM	#5
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: 99 ECSB W/4L80 shifting.... weird... Yup, I bought my truck used in 2005 and I thought there was something wrong with it too (TC wouldn't lock on interstate) the first winter I owned it. This morning was really the first cold morning I've run the truck and it was doing the same as described above, holding onto shifts longer. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!



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