rough 1st to 2nd shift - 2000 Jimmy

My 2000 Jimmy is shifting rough from first into second, but it only does this when hot after drving stop/start for 30 min or so.
National Trans. repair chain "A" wants to rebuild for 2K$ - National chain "C" says nothing is wrong. I have already had EGR valve and pressure control solenoids replaced.

Any opinions?

GM has a bulletin out addressing this issue. A bore in the transmission valve body wears causing the valve to bind. Pressure builds behind the valve eventually forcing it to move, when it "pops free", it causes a harsh 1-2 shift. Find a transmission shop that is aware of this issue and have them repair it. It involves removing and repairing the valve body, not the entire transmission.

Could this also be a problem on a 97?

If the 1-2 shift valve binds in its bore, it will happen to ANY automatic transmission.

Is this a problem that gets progressively worse over time?

My 2000 Jimmy is shifting rough from first into second, but it only does this when hot after drving stop/start for 30 min or so.
National Trans. repair chain "A" wants to rebuild for 2K$ - National chain "C" says nothing is wrong. I have already had EGR valve and pressure control solenoids replaced.

Any opinions?

A is rebuild happie.
B does not know what they are doing.
Beware of Transmission chain stores. some good and a lot not so good.:grinyes:

As Old Master says. Check around.

Check around Ask around
Word of mouth.
Family friends coworkers neighbors business people and delivery people.
Mailmen and parcel delivery people get around and notice a lot of stuff.
Even a good parts house knows what shops are good and not good.
Chamber of commerce and better business bureau and city hall.
If you find a good referral to a repair shop go look them over and talk to them.
Look for a clean looking busy place with nice people running it.
Ask a few questions and ask about their qualifications and training.
Not all places have trained tech/mechanics.
If they do not find a place that does.
Even all dealers do not have all trained techs/mechanics.
MT

Is this a problem that gets progressively worse over time?

Anything that has moving parts, something wears... yes, it will get worse the more it wears. Eventually, when the pressure can not overcome the binding condition, it will not shift out of first gear.

I have a 2000 Blazer LT 4X4 that is doing the same thing. For the valve body repair, is it just the replacemen of the valve or is there more to it than that?

Automatic transmission valve body repairs should be left to an expert. The valve body is a precision hydraulic assembly containing several valves, bores and passages, not something a DIYer should attempt repairing. To answer your question, yes, there is more to it than just replacing the valve.

I was not planning to do it myself. However, i am a little weary about going to another transmission shop. When i first noticed the problem the first transmission shop i went to quoted a little less than $5000, the next shop was $3000 and the last place i went to was just over $1000. The next place i go to i plan to ask them what they are going to fix and how it will be done and if it matches what i am told here then that will make me feel a lot better about putting out the cash. So i just want to have a rough idea of what they will repair.

BTW
Would it be better to replace the entire valve body?

That is an option. If you're comfortable with removing the transmission oil pan, (about 16 bolts) and replacing the entire valve body, (a boatload of machine screws) and trans fluid dribbling into your arm pits, it's not a bad job. If you've never done it before, it will probably take about 2.0 hours start to finish. There are several web sites that carry valve bodies. If you're skeptical on your abilities, let a pro do it.

Thanks Old_Master. This is not a job for me (i knew that from the start) and i will take it to a pro. As you can see from the previous quotes that i got and the huge range in prices i just don't know who to trust and i don't want to end up in a fight if i get ripped off or the job is not done right. I will follow your advice in looking for a qualified shop (previous posts) and now that i know what needs to be done ( i can ask the right questions and i have an idea of what the correct answer should be), so that will make it easier to pick a mechanic.

Thanks for all your help.

Good choice. You have an idea of what you're up against, so talk with the technicians, not the service writer. If you feel comfortable with them, and they treat you with respect, and give you reasonable answers to what they want to do and why, that's a pretty good indication of a quality repair shop. I don't know about Canadas laws, but the state of Michigan requires technicians to be certified. To a certain extent, it helps keep them accountable. Too many "black marks" on their record and the state pulls their license. Good luck and keep us posted.

I had the repair done and it is working like a charm. I have not taken it out on the highway as yet but i did drive it home in heavy traffic and the shifting is smoother than before. The real test will be next week driving back and forth to work.

Thanks

I had the repair done and it is working like a charm. I have not taken it out on the highway as yet but i did drive it home in heavy traffic and the shifting is smoother than before. The real test will be next week driving back and forth to work.

Thanks
What was the repair and how much did it cost?

The repair cost me almost $400(CDN).The tranny oil and filter was also changed at the same time. However, the problem has started again but the conditions on whenit occurs have changed. When i first noticed the problem it ususally started after about 1/2 hour of driving (either city or highway and after shutting off the vehicle for about 5 minutes) and this was during mid July/early August when it was very hot. Now as it is colder, after about 10 minutes of driving the rough shifting starts up (the shift from 2-3 has also become more noticable). I am taking the car back to the repair shop that fixed it the first time and lets see what they say.:banghead: