Couple Issues

biochemist · January 4, 2006

Happy new year everyone ...I have a couple issues I would like some help on...

1) My speedo has been jerky for a few months now, also "chattery"...now it is stuck on 80 MPH, with the truck off! I think there may be a TSB on this...anyone post it? All other guages are fine...My service rep said he would need to duplicate the problem...well, I have photos for him too!

2) Just recently, although I think it has happened a couple other times, I have been getting a split second "weird feeling" on take off...a moment of hesitation. It seems to go away after a mile or two of driving? Related or not, now, this evening I stopped at a light and as soon as my foot left the brake pedal, I heard and felt the tranny shift into first? What is that about?

I think it is the condition that people have documented about the truck not sending the right signal to the tranny for downshifting. Now that I remember I think I may have noticed this a couple additional times since I bought her 18 months ago...it did not bang or hard shift in or anything, but shifted as soon as my foot left the brake...so fast I could no have pressed the gas anyway. Some people say thier truck revs to 1000 rpm then bangs in...this has not happened to me, yet.

Also, I think one other time this evening it may have quickly shifted from 1-2-1 really quickly right when I hit 0 MPH at a stop sign? I felt this shift patteren, it was strange, I thought it was some bumps in the road, but I wnet back to check and it was smooth...note I did not hear anything, just a feeling.

Those are the issues...any comments? Other than the 2-3 clunk I have, shifting and power is fine. Not sure...I assume the speedo is a non-issue and will be replaced...not sure about 2 as I already have the updated PCM flash from May 9.

What do you guys think? VSS, tranny issue, just the way it is...? As long as there is not a durability issue, which some on the site have led me to think, I suppose it is not a big deal. Let me know about your experiences, thanks, later,

mmmikkke · January 4, 2006

When I had my '86 K20 (chevy 3/4 ton 8600 GVW), I remember thinking this will be the last cool trans I will ever have. That trans, being hydraulic rather than electronic, was entirely predictable. And since it was designed back in the '60's, it was unobtrusive and it responded to the driver very elegantly. And it was one of the last years GM allowed us to have a trans that didn't have a lock-up torque converter. That trans was sweet.

None of the electronic shift transmissions I have owned since then have measured up in my opinion. The 700R4 was a turd of a transmission. The 4L60E that I had in my 2002 Z71 was ok, but it did exactly what you've described in your post. It did it enough in the last few months that I owned it that it was the reason I bought a new truck, and I made sure I didn't get one with a 4L60E.

As you may know, I've since discoverd that the 4L80E has its own quirks, but at least in normal driving it's unobtrusive. It doesn't stutter like the 4L60E you have (and that I had). Its only fault, as far as I am currently aware, is the bulls**t upshift that happens when it shouldn't, and I've got my own thread runnning about that. Click here.

Now that you've noticed this, I believe you will be continuously annoyed by it. You could do what I did...

GM says it's happening in just a few of the 4L60E's. I think the % is much higher, like maybe 90% of them. Most people just don't notice. They're too busy talking on their cell phones.