4L60 to 4L80 transmission issue on 2007 Silverado with 6.0L

[Rare87GT]

Ok got a 2008 Express Van TCM tune. Imported it and it worked. Now the issue is getting the truck to shift. Can you look at the log and tune file and see why it is shifting so high and not going into 2nd. I'm not familiar with LS tunes typically as I tune my 3800 Supercharged setup with way less parameters.

I set the shift rpm at 5800 and the mph at 49mph. It went to 53mph and 6700 and did not shift. What gives?

[Alvin]

That's my issue. How do I figure out which one is the happy one to use? If I use the one that works for the speedo, then I get the 0700 error code. If I get rid of the error code with the other flash, then it won't read speedo on HP tuners scan. The truck speedo itself works no matter what. I don't want to keep using up credits spending $100 to find out which one works or which one doesn't. That's my next issue lol.

That was my point. If the speedo works. Than it is communicationg. P0700 is TCM wants the check engine light on. There should be some other trans related code on for P0700. A solenoid code or something like that is likely on.

[Alvin]

Ok got a 2008 Express Van TCM tune. Imported it and it worked. Now the issue is getting the truck to shift. Can you look at the log and tune file and see why it is shifting so high and not going into 2nd. I'm not familiar with LS tunes typically as I tune my 3800 Supercharged setup with way less parameters.

I set the shift rpm at 5800 and the mph at 49mph. It went to 53mph and 6700 and did not shift. What gives?

The part throttle and wide open tables should match. If they don't you will likely have problems. The MPH should be slightly lower than what you calculate it should be with converter slip considered. It doesn't sound like it was calculated right if 53mph = 6700. I would bet the real number would be lower mid 40's.

[Rare87GT]

The part throttle and wide open tables should match. If they don't you will likely have problems. The MPH should be slightly lower than what you calculate it should be with converter slip considered. It doesn't sound like it was calculated right if 53mph = 6700. I would bet the real number would be lower mid 40's.

Did you see the VCM scan I have showing 6700 is around 53mph from when we did a few test runs? I'm just curious on how much lower it needs to be, etc.

Do I need to update all part throttle shift, etc. I'm just trying to find the right shift points here on everything so it will shift at wide open. It shifts fine part throttle, etc it seems. We just don't want to put too many miles on it if it is not right.

[Rare87GT]

The part throttle and wide open tables should match. If they don't you will likely have problems. The MPH should be slightly lower than what you calculate it should be with converter slip considered. It doesn't sound like it was calculated right if 53mph = 6700. I would bet the real number would be lower mid 40's.

Here is the VCM scan showing 6700 and 53mph on the scan we took. That's where I got that from.

[Alvin]

yeah my point was if that was the case "5800 and the mph at 49mph" is seems wrong.

MPH and RPM have to be hit for it to shift. allow for some converter slip and a little time to complete the shift.

[Rare87GT]

yeah my point was if that was the case "5800 and the mph at 49mph" is seems wrong.

MPH and RPM have to be hit for it to shift. allow for some converter slip and a little time to complete the shift.

Completely understand. I know you are trying to help me. I'm just confused why it won't shift at all at WOT. What mph and rpm should it be at you think? I was hoping I would at least have a baseline to go off and then tweak it. The first time we tried it went all the way to 6900rpm and 55mph, no shift. I could understand it shifting way late, etc but it just won't shift period. Even if I was off for example by a few mph or rpm shouldn't it still shift? I could put the mph at 30mph and the rpm at 4000 or something and I feel like it would still go all the way past that and still not shift. It just won't shift period at WOT in the 1-2 shift.

[Alvin]

Make sure the 100% TPS column in the part throttle tables match the WOT tables. If it doesn't it might not shift.

If you observed 55 mph at 6900 RPM I would think 5800 RPM would require

55/6900 = 0.00797 * 5800RPM = 46 mph.

Use some math like that to help get you in the ball park. Just please make sure part throttle and WOT tables are the same or you will have problems.