Transmission shifting hard

[bassgas]

2004 Yukon xl when just putting around Transmission seems to shift more forcefully is this normal. It has 166k on it. Had fluid and filter and flush last summer any thoughts

 

[retiredsparky]

Have you checked it for codes? Use a $15 hand siphon pump to take a sample of your transmission fluid or drain some fluid into a clean bucket and look for metal particles. Fluid pressure should vary depending on need. The pressure regulator is variable and controlled to ensure good shifts. If you have fluid contaminated by particles, that will cause lots of problems, one of which is poor control of pressure. There isn't any extra room for stray metal and friction plate particles in the hydraulic controls. You can also send in a sample of fluid for testing.

When you have it scanned look for P 0748 and P 1870 codes. You can google those codes to read about what they mean.

 

[6speedblazer]

any codes?

what gear changes are harsh? 1-2 only or all of them?

 

[bassgas]

any codes?

what gear changes are harsh? 1-2 only or all of them?

1-2 only I checked fluid look good and smelled ok but level was high on dip stick should I pump it down to proper level?

 

[afpj]

Fluid level on these 4l60 trannys Is a matter of debate. Some people think these trannys like a slight overfill. At your mileage however, it may will it be a worn separator plate or valve body issue. Search on this form for hard 1 2 shift and you should come up with several threads on the topic

 

[6speedblazer]

Fluid level on these 4l60 trannys Is a matter of debate. Some people think these trannys like a slight overfill. At your mileage however, it may will it be a worn separator plate or valve body issue. Search on this form for hard 1 2 shift and you should come up with several threads on the topic

This is what i was going to say.

Most of the time its a worn tcc solenoid bore.

 

[iamdub]

Ever cleaned your MAF sensor?

 

[bassgas]

Ever cleaned your MAF sensor?

No I never have is there a link showing how to do it

 

[01ssreda4]

Load determines shift firmness, MAF determines load. If the trans is being commanded to shift firm, the MAF is the likely culprit. A scan tool will help determine this.

 

[shoplizard]

Tcc regulator valve problems were an issue in the mid to late 90's after that the valve bodies were modified to correct that problem which caused the tcc slip codes to set and cause harsh shifts. Another item that will cause a harsh 1-2 shift is a broken 1-2 accumulator spring located in the case above the valve body. On some early models, there were some software updates to correct a harsh 1-2 shift. These are some items I can think of right now addressing your harsh 1-2 shift. P.S. be sure to correct any emission codes in the pcm before checking mechanical issues, some can cause harsh shifts (high line preesure) if they are emission related and cause you to chase your tail if they are current.