H3 has 200k on it. Bought it used about 80 k ago. Car was and still is immaculate. Yesterday it started refusing to downshift. Just go into neutral when it kicks down. Today it stopped downshifting when you slow down or stop. Then it stopped upshifting from 2-3 automatically. Keep in mind you can manually shift it up and down into every gear and it pulls well. Fluid Is brown but not burned bad. Fluid Isperfectly full. Is this a solenoid problem and if so which one?

 

When did you changed transmission fluid last time? Or not even once in those 80k?
Do you change fluid once it is burnt with the rest of transmission?

 

I personally have never changed it.

 

Did you took your truck to mechanic at some point to change transmission fluid?
Look into owners manual for service interval, for transmission(50k miles!!!!).
If fluid has not been changed, do it now, preferably full flush change. Changing only few liters in pan won't do too much good, but will be better than nothing.
There is about 11l fluid total in transmission, dropping pan you can only change less than 5.
Fluid functionality decreases over time, hope your transmission is not destroyed as well.

 

Time for a rebuild. You are at or beyond the expected service life of your 4L60/E Trans in a 4X4 heavy brick shaped vehicle, especially when fluid and filter have not been changed at proper intervals. Best part is, you get to add in some serious HD performance Trans parts of your choosing, like a Monster Sunshell etc.....

You could try a fluid and filter change now to see if that will get you temporary improvement. Once they get HOT and Cruddy, they wear out.

I have never done a Transmission flush on any vehicle I have owned. Drop the Trans pan, let drip into catch bin, change filter. Add a drain bung and plug to the pan, install fresh gasket when re-installing Trans Pan. Fill with Dexron VI, drive for couple weeks. Drain fluid from new Trans Pan drain plug, refill, drive. Repeat if you think you just gotta.

 

Agree with this diagnosis...[
QUOTE=Doc Olds;381758]Time for a rebuild. You are at or beyond the expected service life of your 4L60/E Trans in a 4X4 heavy brick shaped vehicle, especially when fluid and filter have not been changed at proper intervals. Best part is, you get to add in some serious HD performance Trans parts of your choosing, like a Monster Sunshell etc.....

You could try a fluid and filter change now to see if that will get you temporary improvement. Once they get HOT and Cruddy, they wear out.

I have never done a Transmission flush on any vehicle I have owned. Drop the Trans pan, let drip into catch bin, change filter. Add a drain bung and plug to the pan, install fresh gasket when re-installing Trans Pan. Fill with Dexron VI, drive for couple weeks. Drain fluid from new Trans Pan drain plug, refill, drive. Repeat if you think you just gotta.[/QUOTE]

 

CLEAN, FLUSH, & CHANGE FILTER!