2008 H3 automatic, 110,000 miles.....had 1 coil pack replaced, and 1 Throttle Position Sensor since new....not bad...

However, I left yesterday from to go out on a job 250 miles away, at a stop light, it shuddered a little when pulling out, next stop light, it shuddered then it was just like being in neutral, no matter what gear I tried, engine just revved with no load,
I put it in park then switched it off, cranked it back up, it was ok... Till the next stop light, repeat, at this point I turned around and headed back home, I had to do this same sequence about 5 times in 20 miles, It shifts fine, and could run 55 mph but with just the slightest tap on the throttle, it would do it again.....
To me, this doesn't seem mechanical, if the Trans was shot, I can't see how switching the vehicle off then back on would temporarily fix it, I think it has to be electrical....
Has anyone else ever encountered this????
I had to drive my 92 Jeep Cherokee (HRV) with 300,000 + miles to my job. When I get back home next week, I gotta deal with the H3

 

When was the last trans fluid and filter change? The 4L60-E is very persnickety when it comes to dirty fluid and internal crud.

Pull the dipstick and check the fluid: what color is it, what does it smell like?

If you are not throwing any codes, it is highly unlikely that there is an "electrical issue". Only way to tell is drop the pan and see what you have going on with the fluid and any junk on the bottom of the pan.

 

Will do....but will be a few days, 250 miles from home working 16hr nights the check engine light was on, does anyone know if Advance, Auto zone, etc will do a deposit loaner on a code reader? I think it's OBD2, but not sure,

I'll drop the pan and check things out, when the TPS failed, 80k miles ago, it did something very similar, had to be towed and
But was fixed under warranty,
I will put a big magnet in my drain pan to catch any metal, I've done this before to check for spun engine bearings in other vehicles
Would a trans shop want to see the fluid? As sure as I don't keep it they'll ask for it.....

Any suggestions as who NOT to get to fix it? Heard bad things about AAMCO
Thanks for your help,

 

In another web forum, a guy in Kuwait described almost the exact symptoms, his turned out to be some wiring that had rubbed the housing until it grounded out something, turning the switch on and off would reset the fault until vibrations would let it ground out again....what I recall from his fix, was that the Trans still had to be removed.....said there was GM TSB about it, but I can't seem to find any more details....

Either way, it's looking like I'm gonna have to pony up some cash........

 

Update, I dropped the pan and fluid was not new but also not too bad, (ive seen worse) changed filter,
found a wiring harness with rubbed place and a wire worn down to the copper that was intermittently shorting to the housing, taped it up good and repositioned harness,
not sure what the wire does, but H3 is so far drivable, Maybe I just got lucky, or its not over yet.........

 

I think what that wire is the ISS (internal speed sensor) harness. The common reason for it to go bad would be the wire rubbing and shorting out, to replace it you have to remove the trans since its an internal part.
(I have a CEL associated with it, one common symptom is hard shifting 1st to 2nd)
Still didnt get the time to drop the pan and check and see the wire.

 

Update,
Now trans occasionally shifting HARD, with sound and vibration, throwing codes about Torque Converter, clutches, fluid Hi Temp, Fluid Hi Pressure, etc. etc. pretty much every Trans code that can be set.
I know what that means......It's shot..... I may be getting out of the H3 business.....