New owner, 2008 tahoe ltz, shift points and tuning questions. flexfuel

[bobejones]

Got mamma a tahoe. 5.3L and should be 4L65E. I have a build sheet being emailed directly but have a few questions.

 

1. I am not really a fan o the 4sd mated to the 5.3 but that is what we have. I think mamma will kill the tranny if I don't do some upgrades. I know they become lazy in shifts and I need to firm up shifts and get shift times down a bit. I have to drop the pan for a trans service anyway. Curious what guys are doing with these? I was thinking of running some Seafoam product before chaning the fluid and I hear all sorts of stories about seal damage and such. I just want to get a good fluid change done. Not looking to create a problem.

 

2. The truck has a magnaflow catback on it. It makes me wonder if any ECM tuning was done. I started wondering if there is anyway short of dumping the ECM tune to a PC to just determine if it is factory or not?

 

3. I know the flexfuel engines need a bit to determine fuel grade when filling. I am curious how much time is needed and what to expect on a fillup? I know there were some issues with various tunes (not al GM) that caused engine and valve damage soon after fillup but I think that was limited to turbo engines.

 

 

In short, I need to train mamma on how to drive it right. I can make a tranny live forevery but she can kill one is 100k.

 

 

EDIT: Just learned the truck only has the 4L60E (bummer), and 3.73 axles. I am typically most happy with the 3.73 in these trucks but concerned for MPG on highway with it.....?

[RyanbabZ71]

How many miles on it? We had a 2008 Tahoe that was awesome. The trans was fine (my wife drove ours) and I didnt tune it (my only vehicle). Yours has a 3.73 axle? Didnt know they offered that, ours was 3.42

 

I also ran E85 probably 50-75% of the time. There was no "time" needed. Its usually better to try and burn off as much of the "old" gas as possible so most of the tank is E85.

[bobejones]

98K on this one. I figured it was 3.42 but guess not. However, I guess she will be able to zoom around town with a little less stress on the driveline.