Chevy Manual Trans.

Southerntoys · April 30, 2004

Hi. New to the form, but not new to GM Trucks. I just finished closing the deal on a 1997 K1500 Reg. Cab Z71 4x4 to replace my totaled 1995 K1500 Ext. Cab Z71. When I test drove the truck, it was noted that to shift into 5th gear took a little work to keep it from grinding. All other gears work fine. The truck is approching 90000 miles so i figured it was due for a clutch job and throwout bearing which was negotiated in the price. This morning on the way to work i noticed something else. When in 5th gear de-accelerating off of the interstate off ramp the truck jerked like a trans brake? This confused me so I began to do other test on the truck (long trip to work). When ever i let off the throttle for too long like cresting over a tall bridge it coast very smoothly for a while then someting jerks and lugs the engine down to slow my progress. Is this normal but annoying or is something wrong? This is the first manual I had in a while so I don't know what is normal. I just finished doing a little research on the truck over the internet and the owners manual and I think it has a MG5 trans. I don't think it's the MW3 but won't know for sure for a week till I get back in the truck to look up the RPO code. To follow up on the problem it only happens when you ease up on the throttle to much or for too long while in gear!! Any insite would be greatly appreciated.

citydriver · April 30, 2004

Welcome to the forum

I had 5-speeds in my '88 and '91,had problems w/both of them jumping outa gear, but they were repaired under warranty @ the time...but that was when those tranny's were the 1st generation versions...

But I do remeber both of them doing the same thing when in 5th,but it would slow w/engine RPM's...but its also been 12 years since,so I may not be of much help 2 ya....It could also be a syncro goin bad(thus the grinding),but see what happens when you get it back after the clutch replacement.....GOOD LUCK

Hullie · April 30, 2004

Southerntoys,

Unfortunately, I think this is "expected" w/ the newer manual tranmissions. I had a K1500 5-spd before purchasing my 2500HD 6-spd and they both do it. It's a feature of the pcm added by chevy, which I think it just ridiculous. What it is, is they use the cold start injector to continue pumping fuel into the engine so that it "coasts" smoothly for a while instead of engine braking. Then when it does transition to engine braking (maybe 10 seconds) it jerks down.

I find this very annoying as I use the engine (or would) to avoid using the brakes. Instead, when I need to slow for a car in front of me, the truck doesn't and I end up having to use the brakes. I guess they figure that people who buy manual transmission couldn't possibly actually know how to drive then.

I've also found no way at all to disable this "feature". If anybody out there knows of a way, please let me know.

Hullie

Southerntoys · May 1, 2004

[i guess they figure that people who buy manual transmission couldn't possibly actually know how to drive then.]

Thats what I figured!! All of the manufactures need to stay out of the looking after the public safety or the safety features will take over the automobiles we drive? And you have to ask your self what they were trying to accomplish with this feature? Soon we will be driving with onboard technical assistance telling us to speed up and slow down, your following to close, and please turn your lights on ect. ect..