Tuner to fix shifting in 2000 Tahoe (auto transmission)

[Jerome Nelson]

My mechanic recommended I get a "tuner" to fix the weird shifting I'm getting in my 2000 Tahoe. I'm looking for advice on which device, and how to make the settings I need.


Issue Details:
I had my automatic transmission rebuilt about 6 months ago. It works great 80% of the time. Sometimes it runs perfect! But often, it slips (or what I assuming is slipping - e.g. slow to shift) from 1st to 2nd. Usually, it just feels like a mule and just needs some goading. Other times, it drives like a gocart and is a lot of fun. I'm assuming, that because the problem is intermittent, that it's a electronic issue and not a mechanical one (failing trans).

Two months ago, I told my mechanic (the one who replaced the transmission) that I'm considering having him put in the Corvette Servo, so I can get more responsiveness. He asked me if I've ever updated the onboard computer and I said 'no'. He then recommended I get a tuner, instead of the servo (which wouldn't profit him). The tuner would also make up for the lack of updates to the computer.

However, since then, the transmission has become more and more sluggish - and then GREAT for about a week - and then sluggish again. Super weird!

Have any of you experienced this?! How did you fix it? Did you get a tuner?! What were the results?


Vehicle Details:
2000 Tahoe
5.3L V8
2WD
4-Speed Automatic
4L60E Transmission (rebuilt 6 mo. ago, rebuilt 6 yr. ago)
Everything else it pretty much stock.
NOTE: This has the electronic idler upgrade on it!

I also want the idle to be bumped up from 500 rpm to a bit more. Any recommendations? It would be great if it didn't shake when the A/C is on!


Additional Info:
I live in Central Florida, where it is mostly flat (and hot!) So, we always drive in (D) Drive - My mechanic says this is actually "Overdrive".


Parts I've replaced in last 1 year (incase it matters):
MAF & Filter
MAP
Spark plugs, wires & coils
Fuel Injectors
Coolant Temp Sensor
Oil Pressure Sensor
Valve Cover Gasket
O2 Sensors - Bank 1 & Bank 2
Water Pump & Thermostat
Upgraded Transmission Cooler
Battery

Additionally, I replaced the 2 shifting servos in the transmission pan about 1.5 years ago. I was hoping this was the original problem I was having, but the transmission was failing mechanically, so we rebuilt it 6 months ago.


I really appreciate any and all advice and feedback you guys can give me!!!

 

[Miami-Dade]

@Jerome Nelson Moved you here from 2007-14 section.

 

[Mudsport96]

This sounds like either an internal transmission issue, an electrical connection issue or maybe the throttle position sensor is going bad. If it was the tune, it would be all the time.
Check to see if the electrical connector on the passenger side of the transmission is loose.

If that seems good, then you may need to have someone with a scanner look at how the throttle position sensor is reading. If the computer thinks that the throttle isn't open enough it will not shift right.

 

[Jerome Nelson]

This sounds like either an internal transmission issue, an electrical connection issue or maybe the throttle position sensor is going bad. If it was the tune, it would be all the time.
Check to see if the electrical connector on the passenger side of the transmission is loose.
View attachment 410185
If that seems good, then you may need to have someone with a scanner look at how the throttle position sensor is reading. If the computer thinks that the throttle isn't open enough it will not shift right.

This makes a lot of sense and is very helpful! Thank you!

 

[NickTransmissions]

This makes a lot of sense and is very helpful! Thank you!

Check your servo travel, should be between .075 and .125...Sounds like the band could be slipping in 2nd and wearing out. Intermittent issues can just as easily be mechanical, esp if you dont have any transmission DTCs stored so dont assume they are only electrical or electronic.

Installing a 093 servo aka Vette servo and transgo basic shift kit (SK4L60E) would help if in fact the band is slipping.

Also scan it using something that can render live trans data as well as engine data. Could be the TPS like @Mudsport96 mentiond though the most common symptom of failing tps is super late, harsh shifts.

There are no servos underneath the pan, you're prob referring to shift solenoids A & B.