Hard 1-2 shift

kowalcs · June 24, 2003

I took my '97 Bravada to the dealer last week for some A/C service. Needless to say, I now have more problems than when I took the thing in. One problem I am now having is that after the vehicle is warm, but not all the time, the transmission shifts hard into second gear. It won't do it when it's cold and it doesn't always do it when it's hot. Any ideas? I'm thinking the dealer may have inadvertantly disconnected something. After I picked the thing up, I noticed the check engine light was on. I found a vacuum hose disconnected under the hood, reconnected it and the light went off. This is why I'm thinking something for the trans may be disconnected because I already found something that they inadvertantly disconnected.

NewGuy · June 24, 2003

I bought a 98 s-10 4x4 in February. It had some kind on tranny problem. The person i bought it off of was nice enough to have it rebuilt for me. Ever sence it was rebuilt it has shifted hard from 1st to 2nd periodically. i just got it back form the tranny shop today and they told me that it was something electrical with the tranny. they changed all the swithces in the tranny. i have only driven it about 15 miles so i dont know if its fixed. i'll keep you posted.

NewGuy · June 24, 2003

Have you had the codes pulled?? i did on mine and 1870 was the code!! that is the tranny slip code, but my tranny never slipped. Good luck

Worktruck · June 25, 2003

The tranny won't necessarily slip to create the code. The control module senses the slip and adjusts pressures in the tranny to compensate. Hence the hard shift. BTW Newguy is my son and he just called all bummed out cause it's still shifting hard intermittently. My guess is the valve body. These trannys (4L60's)are known for it.

kowalcs · June 25, 2003

They pulled a code and told me it was a slip code involving the TCC solenoid. The guy at the dealer who I don't trust one bit anymore told me at least $2000 to fix. Needless to say, I went and picked it up yesterday. I don't know what to do anymore. I just put $1300 into the vehicle and don't want to put thousands more into it. A buddy of mine told me about a problem his dad was having with his trans a while back. I guess when the torque converter locked up, it would chatter a lot. He wound up putting some kind of additive in it and it cured his problem and five years later it's still fine. I'm almost thinking of trying something like this(an additive). It's not worth dumping thousands into this vehicle at this point. If I can't fix the trans problem, I might just trade it in. The dealer also wants $700 to fix a a/c condensation drainage problem that I am convinced that they caused when they replaced the compressor. I'm very, very frustrated. Anybody want a '97 Bravada?

NewGuy · June 26, 2003

I talked to a tranny gut today that lives sown the street from me and he was telling me that he's pretty sure its in the valve body. There are two valves that wear out. One in the pump and one in the valve body. he suggested i change them both, because the valve in pump will eventually go.

How many miles are on your bravada?? My s-10 has 91,000

he told me they usually go around a 100k. Maybe you should go to a tranny shop instead of the dealer.

kowalcs · June 26, 2003

My Bravada has 104K on it now. However, after talking to my friend that I bought the vehicle off of and doing a little research, I found out that this exact same problem happened at 47K and 57K. I contacted the dealer today that did the original work and am still waiting for a reply. At 47K, they replaced the valve body and the TCC harness. At 57K, they did it again. As far as I'm concerned, the problem has never been fixed. I really don't think they're going to help me out, but it's worth a try.

I wonder if I would be able to tackle this job myself? Can the average mechanic replace a valve body?

NewGuy · July 7, 2003

How have you made out?? Tomorrow I am taking my truck to the dealer to have my valve body fixed. I'm pretty confident with there diagnostics. My father and i have done some worek in their building. I'll let you know what happends.

jeffdb · July 7, 2003

My 98 Astro is doing the same thing. It has 125K. Sometimes it does it and sometimes it don't. Do these engines have a manual downshift cable to the tranny or is it all electronic? Keep us informed.

kowalcs · July 9, 2003

I called the dealer again today and they aren't willing to help me out at all. They did suggest that I call the GM customer service number and file a complaint. I guess it's worth a try. I was successful in the past going this route on one of my Ford vehicles. I'll keep you posted.

NewGuy · July 10, 2003

Well I got my truck back from the dealer yesterday afternoon($643.19) later. Its all fixed not a problem shifting at all!! They replaced the valve body. The problem that is causing the tranny to shift funny is the valve in the body. At a certain speed the valve opens and sticks causing the tranny to slip. When you stop and the tranny shifts from 1-2nd it has full line pressure to ensure a shift. This causes the banging of gears. If you shut the vehicle off and let it sit for a few minutes it probably wont do it again right away. See about getting your valve body replaced. Find a local tranny shop it might be cheaper. Oh long distance driving should be avoided you'll burn it up.

joe4 · July 12, 2003

They also have valve body repair kits,Sonnac is one.

jeffdb · July 12, 2003

Where can I find this kit at?

joe4 · July 14, 2003

Transmission shops have the kits,you need a reamer to install the kit,the reamer runs about $100 .

I would bring the valve body to the shop so they can install the kit.

kowalcs · July 15, 2003

Well, I talked to a friend of a friend who owns a trans shop in Youngstown, Ohio who immediately knew the problem with my Bravada. Sounds like exactly what you guys are talking about. He told me it's probably giving an 1870 TCC code. He said the Sonnax valve would have to be removed and then have the valve body reamed out and a new valve put in. He said this should fix the problem. He would charge $250 for the work, but I don't want to drive the vehicle four hours down there and risk burning it up. I called a local trans shop and explained all that to them and I'm taking it in tomorrow. We'll see. Hopefully they come up with the same diagnosis. The guy I talked to at the shop seemed pretty honest, which is a lot more than I can say for some of the other shops I talked to. The saga continues.