swampthing

I have a 99 Silverado 5.3 1/2T. I'm on my third transmission. The first was just normal wear and tear, but the second developed a light slip from 2-3 that turned into a huge slip. I recently replaced the converter and transmission with GM remanufactured parts.

I still have the slip between 2-3 it's just not as noticeable, yet. It feels like 2 clunks out, the engine spins up a few hundred rpms, then slips/grabs 3rd. If i let off the accelerator right before it shifts and coast through the shift it seems fine.

I had my tuner double check his work and he said it's fine. I was tired of breaking things and always having my daily driver down so everything is stock except an air filter and electric fans now. It also has a larger trans cooler as well.

The 2nd trans had a bad accumulator piston and another issue which I have forgotten but will try to find out.

What could be causing my 2-3 slip? Is there a tcm on the NBS 4L60Es and I'm getting bad comunication somewhere? Could my pcm just be sending bad info to the trans? At this point I am open to any suggestions.

TIM Z

iTrader: (12)

NO ****!!! Im haveing the same prob!!

My truck eats 3-4 clutches.

I talked to Terry at Precision Industries, he is very knowlegeable on 60 e's. Say's some customers have them running 9 sec daily driver cars no probs, its all how they are built. But an 80 e is a great way to go for sure.

Any Way He told me Altos are not the best choice for a 60e, USE The stock Borg Warner 4x4 GM clucthes .

Also guys mod the springs on the 3-4 pack and thats no good , i cant remember exactley what Terry said as im am no trans guy, but he has the answers.

When guys use thinner clutches to put more clutches in a pack, they cant dissapate the heat that the thicker factory clutches can.


He aslo said that When you have a hard 1-2 shift fluid can get behind the 3-4 clutch pak and it has an adverse effect on the 2-3 shift.
You may have some other issues also. Terry spent some time with me on the phone so i can get my trans working the way it should. I bet he would help you too.

Im giving my 65E one more shot, if not im trashin the ***** and gettin an 80E.

Its just a lot to ask of the 60E in a heavy powerful truck im told. But it can be done .

My last 65E in my Turbocharged Z71 was great so i still have faith.

I bet yours is not a tune problem. I thought mine was also and i had TJ raise my line pressures to kill and it still didnt help as it was a mechanical issue.

Good luck!

KozzyJr

tim ive read some threads that involved your truck and with that kinda power you should just swap to a 80e you wont regret it! when my 60e dies, i all ready have a 80e for a new home lol

TIM Z

iTrader: (12)

I hear ya Bud!!

You are very smart for getting an 80e ready. I will be doing the same for the future.

I'd really like to get this 2-3 slip issue figured out for my self as well as Swampthing.

I have a lot of money in this as well as my converter so i hope i can make it work. I have a great trans builder who is helping more than i can imagine, Im very glad i went to him, im positive we will get it figured out.

swampthing

When you do let me know. I have my old 99 PCM I'm going to install. I read on another board some PCMs just have issues so I'll try that.

6789olds

has anyone heard of a ground issue causeing a a slip and the 3/4 clutch burn up ?? a shop told me this about my 96 4l60e that it needed a extra ground to prevent this .idk if this is true or not

Truckshop

iTrader: (17)

that was only a issue on the 96-99 black box computers for the obs trucks.

6789olds

ok cool . were would the ground need to be added ? if you know ?

BLACKND

iTrader: (5)

Been having the same or similar issues with my 07 NNBS 4.8 liter. Had my tuner check everything in the tune and he says its right and have no reason to doubt him

My issue started out mainly getting onto the freeways going to WOT downshift, the 2-3 shift would just bounce off the rev limiter, or so it seemed. It was almost like I had hit the top speed limiter. If I go WOT and let off slightly before the shift it will go. Now it seems things are getting slightly worse, I don't drive the truck hard most of the time, but its starting to slip a little at moderate throttle say 75% acceleration at the 2-3.

I talked to a local mech shop that I trust, that does a good bit of performance builds too and he's going to look at it for me when I get the money. He definitely wants to add a vette servo, which I've debated on doing for a while anyways. I don't think I want to build the tranny much, I don't really race anymore, and plan on keeping the truck for a while, maybe add the servo, hardened seperator plate and repair what ever the issue is with the 2-3 slip.

The truck has limited performance mods, and I mostly grandpa it around. I've had all the TQ management turned off since about the first month of ownership and has almost 90K miles on it so I guess I've been lucky.

Beatdown Z

iTrader: (18)

My mom's 03 Trailblazer with a 4L60E had a 2-3 slip/flare, so I swapped in a Corvette servo and now it shifts perfect(even after 30k miles). I later found out that a 2-3 slip/flare can be caused by damaged servo seals. So switching to a Corvette servo will give you firmer shifts and potentially fix your 2-3 shift issues. Win win.