94 K2500 Suburban Temperature-speedo-shifting

[killerdalz]

I have a 94 K2500 Chevy Suburban. 4.7liter(454 cu in.). 4L80E Automatic transmission. The speedometer will not function until the temperature gauge reaches and/or exceeds 180 degrees. The transmission will not shift out of 1st gear until the speedometer functions. After the temperature reaches 180 or greater and the speedometer is functioning, the transmission appears to shift properly.

 

I have replaced the VSS on the crankcase ($155) and that wasn't the problem. I have tried driving with the VSS disconnected while the temperature gauge is 180 degrees or greater, and the transmission will not shift out of first gear (rpms up to 3000).

 

I have noticed the engine does take some time for the temp. gauge to reach 180 degrees. In addition, the temperature gauge will fall below 180 depending on the conditions which causes the speedometer to not function and the transmission to shift down. I could be travelling at a speed of 45 mph and if the temp gauge drops, the transmission shifts down.

 

I have spent hours searching and reading posts with no luck. Open to any thoughts...ideas...suggestions....

 

Thanks for reading.

IE

Portland, Oregon.

[redvett]

The VSS sensor is on the transfercase not the crankcase. The coolant temp should be between 195-210F. Have someone check all data with a scanner to read CTS, VSS and all other data to see whats not correct.

[killerdalz]

Thanks for correcting me, the transfer case.

 

As far as checking the data, would a check engine light need to be present?

 

The VSS sensor is on the transfercase not the crankcase. The coolant temp should be between 195-210F. Have someone check all data with a scanner to read CTS, VSS and all other data to see whats not correct.

[redvett]

No there is streaming data from all sensors and looking at what the sensors are telling you can solve many problems. Be sure you or the person scanning has a list of correct info, its in any FSM.

 

Thanks for correcting me, the transfer case.

 

As far as checking the data, would a check engine light need to be present?

 

The VSS sensor is on the transfercase not the crankcase. The coolant temp should be between 195-210F. Have someone check all data with a scanner to read CTS, VSS and all other data to see whats not correct.

 

[killerdalz]

May have found someone that has a scanner. Thanks for the information!