GTO 4L80 on dyno how to force lockup?

[tom's2005gto]

2005 GTO converted from M6 to 4L80e using a A4 donor harness, T42 and the car flashed to A4 using Tech2. Built 4L80 with Yank SC3000. Car was recently at the local speed shop and strapped to their Dyno Dynamics. Made 680rwhp and 1000 torque. But they can not get the converter to lockup on the dyno and the car blows through the converter at 5200rpms and falls on it's nose.

Is there a trick to programming the converter to lockup on the dyno? They tried everything they could think of. Car runs great on the street with no signs of any issues.

[LSxpwrdZ]

Make sure VCM Controls are enabled in the trans diag. tab and use the scanner to force lockup. At least thats worked in the past for me.

[DSteck]

You sure it's pinned out properly?

[tom's2005gto]

We are using a factory main harness and the pcm4less adapter harness for 4l65 to 4l80. It runs fine. Just won't lock up on the dyno. But apparently is a common problem with high hp cars and hpt.

[DSteck]

I haven't had any issues locking mine or my buddy's at over 1000whp.

You've tried forcing it in the scanner, right?

[tom's2005gto]

Not sure what all the shop did to attempt it. But they tried everything they could think of. They made 21 pulls. So it's not like they gave up quickly.

[DSteck]

Making a bunch of pulls doesn't mean they know what to do.

Find out what they did to try and make it lock.

[tom's2005gto]

Here's the email "Commanding full converter lockup, before 5200rpm everything looks great, then u can c what happens"

Since then they told me they attempted to command third gear only, sorry, I don't know all the technical data.

[DSteck]

It's hard to say anything based off of that. If the lockup function works properly, then it's either user error on the dyno or the clutch isn't strong enough.

[LSxpwrdZ]

The way I take that message is it held locked up to 5200 where it released. If that is the case then they didn't have the Trans Diag. settings setup properly. There is a Scanner Control limit that has to be maxed out on RPM and Speed so that scanner controls stay enabled at all times....

[DSteck]

The way I take that message is it held locked up to 5200 where it released. If that is the case then they didn't have the Trans Diag. settings setup properly. There is a Scanner Control limit that has to be maxed out on RPM and Speed so that scanner controls stay enabled at all times....

That is defaulted to 3200rpm though and only applies to manual gear commands and not TCC. I bet the TCC isn't strong enough or it's just not even commanded to lock.

[LSxpwrdZ]

Could be the harness... I don't personally like the conversion harness that use a 60E segment to control a 80E transmission especially when there is the capability to just flash an 80E file to the TCM.

[DSteck]

Unfortunately there's no 80E file that works for E40s.

[ericwilloughby]

Are u sure the lockup works at all? I've had many problems with the tcc valve in the pump itself not working. 1 on a fresh build from Phoenix transmission

[LSxpwrdZ]

Dave I show on a stock calibration on a 2005 GTO that 5500rpm and 100mph for the CMD Gear Control Limits. If this limit is met the convertor will unlock as well as the commanded gear in the scanner will be ignored.

If the convertor works on the street then setup the convertor to lock in 3rd gear at a low mph and keep it locked all the way up to 100% TPS. Then set it up so that the transmission will not downshift from 2nd until it reaches a really low speed and so that it will not upshift into 4th. That should make it happen if the convertor is working as it should.

[DSteck]

Weird. The stock one I opened showed 3200. I've never had it affect the TCC, only the commanded gear.