4t60e 1st gear slipping

[Juha]

Nothing out of the ordinary. Just accelerated normally from lights and 1st gear slips. All the other gears ok.
Im not gonna fix this anymore if the trannny is gone.
Is there any possibility that the vac.modulator is broken?
Trannys got new oil and filter.

 

[zora]

How long ago was the filter and fluid changed?
Was there an excessive amount of material in the pan when it was changed?
Have you checked the fluid level?
Modulator effects the point where it shifts nothing to do with slippage.
In some cases a Transgo shift kit will help.

 

[Juha]

2months ago filter and oil. The pan was like new inside. Fluid level is ok.

 

[Juha]

Well. Now it works just fine. There must have been something wrong the oil pressure/flow.

 

[zora]

Next time you have an issue find a shop that can read transmission codes.