So, last night going to work, I noticed that the truck would take 2nd gear really high, then shift right to fourth (OD) and then lockup the TC as usual. I tried to accelerate nice and easy, 2nd went pretty high (up to ~4K rpms), then it seemed to go into neutral for a second. I let off the gas, then it went into thrid, fourth, and TC lockup all in about 2 seconds.

Now the thing that confuses me, and I can't find symptoms like this anywhere on the site is that if I select 3 instead of OD, it will shift into 3rd. It still takes 2nd gear fairly high, but it is a definitive shift into 3rd, no neutral or slipping in between and the lockup works on 3rd as it should.

This happens cold or warm. When it is in 3rd, I can give it enough gas to really go, but not downshift, and the truck hauls *** without any slipping, so I think I can rule out the TC/clutch packs. Does this sound like a solenoid problem? Or a wiring problem? I don't think the tranny is going out... It was rebuilt at 220K, and the truck has 390K now.

Any help is appreciated...

 

I had the same thing go out 99 S10 4x4 with 4L60E tranny
the Hi clutch pack went out
tranny needed rebuilt
so off to A good local Tranny shop here in Las Vegas
and 1300 bucks later im back up crusing
if you have it rebuilt ask for the old parts back !

 

I'll keep that in mind, but I'm going to check over everything else before I get to that point.

I checked the fluid, it looks red, maybe a slight tinge of brown. I really don't know when it was last changed. I'm going to change it this weekend, and put in some mr. tranny fluid with it.

Any issues with changing fluid/filter on it? Will it make things worse? I'm not going to flush it, I know that's a headache waiting to happen... I would like to know if a simple fluid change will be more harm than good...

 

So I went today to my friend's shop and had the fluid/filter changed. He showed me the fluid and it was red as if new. I have not changed it in the year I've owned it, and I don't know when the previous did it, if at all. He told me the filter had nothing to be worried about. There were no metal shavings or any abnormal oddities in it. He completely flushed the old fluid out, and didn't see anything wrong with what was coming out. Maybe $120 wasted? But meh, preventative maintenance if anything...

He took it out for a spin, and noticed if you accelerated normally, it would switch fine into 3rd, but he said it seemed like a "lazy" shift. I went with him so he could show me, and sure enough, at regular throttle from a stop, it shifted fine, but as he said, seemed to be a little lazy going into 3rd. If he gunned it off the line, it would quickly get up to speed, but when it went for third would just rev up. He let off, and it switched into 3rd, then 4th right away. He tried it again, and kept the pedal down. It revved for about 2 seconds then engaged into 3rd, then again 4th right away.

He by no means is a transmission specialist, but says that it may be something either in the valve body, or solenoids for the 3rd gear. He said if it was the TC going out, it would slipping/shuddering in third when you gave it more gas. He stuck the selector in 3, and floored it (we were going about 90KPH, so it didn't downshift) and it just took off like a bat outta hell. No hiccups at all.

Now, should I spend the money to get the tranny thoroughly looked at, or do you think it could be an easier fix like a solenoid? Trans shop wants $200 for a full diagnostic, that's a pretty hard pill to swallow if it comes down to having to pay $2000 for a rebuild