Just hit 175K last weekend and today my H2 started acting up. From a stop I will accelerate but my truck wont shift from 1-2 until I reach around 5k RPM AND I have to let off the gas, then it shifts to second.

Also on the highway when I punch it (from around 50MPH) it drops into what sounds like neutral. The RPM's skyrocket but I go nowhere

Im not a transmission kinda guy so Any help would be great!!

P.S. Yes I checked all my oils and trany fluid

 

It is slipping, time for a rebuild or a replacement I think.

 

I hope not. it runs fine wine it's in 2nd and third. It's just the shift points.

 

I would say the same. Rebuild or replace.

 

If it weren't for this factor I would first guess TPS sensor


when I punch it (from around 50MPH) it drops into what sounds like neutral. The RPM's skyrocket but I go nowhere

 

Well... just swapped out my 1-2 shift solenoid. We'll see how it goes in the morning. How much does a re-build cost average? Could I do it myself? lol

 

UPDATE:

The trany fluid was pitch black, probably never swapped. Also changed my filter out and the 1-2 solenoid. Its still not shifting from first too second by without letting off the gas. 4th isn't slipping out anymore it just feels a bit sluggish now from 50-75. Im going to try swapping the TPS and see what happens.

 

Thats not a good sign when ATF more closely resembles your engine oil. My thoughts are even if you get your shifting issues straightened out you are going to lose the trans in the next few months (or sooner). So while it's getting you from point A ton B start saving or looking around for a shop you can trust for a rebuild. And in the mean time stop provoking it to try and make it slip.

I know their was a guy on my local C list selling a 30,000 mile GM replacement trans & converter for $500 it was clean outside with all kinds of GM remain stickers. It's gone now, checked for you.

 

Yup no beating around the bush now. My tranny is stuck in first now the question is rebuild myself or replace :/ what do you guys recommend. Has anyone done a rebuild them selfs?

 

I used to handle trans rebuilds at one of my previous jobs, unless you have a big hospital clean work bench and parts washers with a rich history and working knowledge in hydraulics don't attempt it!! Not being familiar with your mechanical ability - if you even knick and o-ring putting the valve body together it won't shift or some other crazy issue that will make you pull your hair out.

I would :

1. look for a used trans out of running hummer (maybe a hail damaged truck)and have a shop install it, they usually get $150ish out and $150ish back in..
2. Take it to reputable trans shop and have them handle the entire task.

Me personally I would have a trans shop handle the repair (only because I have done it a 100 times, it sucks without a lift & trans jack)