Hey guys,

I have a 2002 Avalanche 1500 2wd with a 4L60e tranny 150k miles. Earlier this year I was having issues with the trans taking too long to shift into 2nd from 1st. It would happen after a complete stop. It's almost like I had it in "hauling mode". It would shift at around 2500 or so. It would do this every once in a while, then it stopped. I've never had any other issues with the trans.

Fast forward to this Monday. I'm taking off from a stop and when the trans shifts from 1st to 2nd it felt like it slipped or "let go". Then it grabbed 2nd and continued to drive normal. It did this a few times this week.

I'm thinking it's the solenoid. What do you guys think?

 

I suspect your band is worn and you will soon loose 2nd completely.
Here is a similar thread - start at post #2 where I explain how to measure the end play of the servo and some options to get a bit more life out of the trans.

https://ls1tech.com/forums/automatic...t-trouble.html

Once you report the servo end play, we can go from there.

 

If you think its the solenoid swap in a new one into the valve body harness (its pretty easy) and take her for a spin. It it's still acting up, might be time for a rebuild. 150k on a stock 4l60e is plenty of time for it to go bad.

 

I'm going to replace the solenoids and harness this wknd. Worse case scenario if it doesn't fix the issue at least I've already purchased some parts towards a rebuild.

Btw, it's been behaving right these past few days.

 

4L60 in a 04 tahoe, has the 1-2 soft slip shift, sometimes once in a while it will not shift down at a stop and when i accelerate its starts shifting back into first,( once in a while). 52k later still have the same trans. simple shift kit may help. 206k on i think "original" transmission. i am the 2nd owner so not 100% sure. i am doing well so far. (fingers crossed)

 

Now that you mentioned it, my Avy used to do that as well. I would come to a stop and when I would take off it would still be in 2nd. After a few seconds it shifts into 1st and all is well. It did this a few times last year or the year before. But hasn't done it in a while.

 

Well guys I never got around to swapping in new solenoids. On the way home from work last night the trans said it loud and clear that it needs a rebuild. I took off from a stop like normal. The trans shifted into 2nd and just before it shifted into third I gave it about 1/2 throttle and the rpms shot up to like 3k and the truck was not accelerating. So I backed off and allowed it to shift into 3rd. At around 40mph I again accelerated and the same thing happened. I had to baby it the whole way home. Anything more than 1/4 throttle and it would slip. When I pulled into the driveway I foot braked it and with about 1/2 throttle she started slipping. The smell of burnt clutches/fluid was very noticeable.

So needless to say I need a rebuild. But I'm still happy. This trans gave me 150,025 hard miles.

This morning I stopped by my tranny shop and picked up a rebuild kit. Do you guys think I should replace the 4 pinion sungear with a 5 pinion version? I don't do any racing with my truck and almost never tow. But I do have a pretty heavy foot when gas prices are down. Lol.

 

Sorry to hear about your trans, but I can't say I am surprised.
I would not bother with the 5 pinion upgrade; for one thing due to recent GM changes to the pinion, quite a few other parts need to be upgraded too.
I would recommend getting the 4L65E rebuild kit as this will have a better 7-friction 3/4 clutch setup; and that is the only difference. That only adds about $10.
I would also suggest the Sonnax Smart Shell; besides being a stronger shell, it also puts lets strain/heat on the rear pinion bearing. That adds about $90.
If your budget allows, get a new reverse drum; the recommended ACDelco one is about $90. With a new reverse drum, you can optionally install a wide band.
Last, get the Sonnax 4L60E-LB1 boost valve; that will tighten all your shifts and increase line pressure (including max line pressure) to reduce wear and friction.

 

Don't Forget a shift kit!

 

A shift kit on a daily driven truck? It's basically the family vehicle.

 

Yeah, I know HomeSchool loves his shift kit, but seems like overkill in this case. The Sonnax boost valve I suggested (above) will firm things up without the complexity of a full shift kit. The boost valve is also trivial to install; a full shift kit is not.

 

Ok I'm gonna head back to my trans shop tomorrow morning and pickup the following parts that didn't come in the master kit:
Separator plate
Sunshell (the beast)
Both shift solenoids
Downshift solenoid
TCC solenoid
Pressure sensor
Wire harness
And a rebuilt converter.

Does anyone have any other ideas on what else to get. Remember...it's a stock rebuild. Just replacing the weak **** that commonly goes bad.

 

Not all shift kits are for performance, transgo makes a shift kit which makes shifts smooth, and helps correct from the factory issues as to why the tranny might blow in the first place. A great choice for not alot of cash to help that rebuilt tranny last, check it out -> http://www.transgo.com/products.php?...dcountview=Yes