2000 GMC Jimmy transmission stuck in second gear.

demolition1155

I have a 2000 gmc jimmy 140k on tranny and after a lil bit of driving it will be stuck in second gear at 3000 rpms at 65mph and a hard shift from 1 to 2 I have checked fluid and replaced 5 quarts of atf fluid and pulled the pan down and replaced all of the solenoids and the filter ,gasket any comments would be a huge help

rusty_cage

there are problems with several of their trannies. I had one do that. there r some software downloads or updates that they can do that may fix it. dealer can do it. there were 50 uodates to the trans. when I had that one and they all revolved around too many up and down shifts the hanging in gear and jerk like yours and mine did. GMC small SUVs are high maintence

thecardoc3

Start by pulling and reporting the codes that are setting. Being stuck in 2nd gear means the system is in limp-in mode so the computer isn't turning on any of the solenoids.

rusty_cage

My comments r based on personal experience and are intended for information. I do not run to mechanic with everything. I grew up fixing our cars at home and I still do in most cases. It is easy for people to just say to all these questions to go to the dealer or shop. I like to think outside the box and offer something other than the obvious

thecardoc3

rusty_cage said:

I like to think outside the box and offer something other than the obvious

The O.P. wrote "I have checked fluid and replaced 5 quarts of atf fluid and pulled the pan down and replaced all of the solenoids and the filter"

IMO thinking outside of the box doesn't mean skipping steps. One must first try to pull codes and see if the computer can help us get a sense of direction. If the computer is detecting a circuit or system fault then the diagnostics would start by making sure we understand how the computer runs that test to generate that code. Once that information is obtained, the regular routine would then have someone follow a trouble tree, but there is a problem. Trouble tree's are useless on intermittent failures. For a trouble tree to work, the failure has to be a hard failure and be present the entire time. People often pull codes and play guess the part which is the most likely reason that this has already had solenoids tossed at it. That's where guesses, even educated ones often lead to.

The things that we have found that can cause limp in over the years would take an hour or two to write down here, and again the majority of it would be considered flawed information because the real information that someone needs is how to test and prove what is wrong. That is done by a combination of tools, which include a full function scan tool, a digital oscilloscope, low amps current probe, the schematic that includes the affected circuit, and logic tables so that you know what solenoids are commanded on/off to select the different gears and from there what clutches/bands are applied. In many cases this would also include connecting pressure gages to the available pressure taps. This all has to be set up, and then the car driven to get it hot enough to act up as described by the O.P. Then and only then can an accurate diagnosis really be made, anything else risks being reduced to nothing more than an inaccurate guess this time (no matter how many times it might otherwise be right).

Thinking "outside the box" in auto repair really means figuring out how to test dynamically, which means live testing, not static.

BTW while a re-flash may be available, it would only be part of the solution. Top independents can handle flash updates just fine, the car does not have to go to a dealer for that.