4L60e Slow Gear Changes

[brindo]

Hi,
I am in the process of trying to tune my VT 5.0 engine and 4l60e with the enhanced bin.

The transmission changes OK at light throttle, but under power the changes are very slow. When the engine was stock the gear changes were normal.

I have logged the transmission slip as per the guide, and the rpm values weren't as nearly as bad as what I was expecting, but will increase the line pressures anyway and see what changes happen. I have tried changing the Desired Shift Times along with the Minimum Shift Time Limit down with little to no improvement.

Does anyone have any pointers on what to change or check next to speed up the shifts? Or any advice on what other changes may be beneficial to improving the shifts and transmission performance?

The engine also has an 85 mm throttle body and the shift speeds are all stock at the moment. I did try and lift these a 5 km/hr but have since returned these back to normal as I didn't really notice any improvement.

Also, does the VT 5.0 have the Torque Management and if so, how do I turn it off or reduce its effect?

Thanks in advance

[Holden202T]

you will find improvements from adjusting the shift times and pressures, but there will come a point where the box just can't do anymore without upgrades like a shift kit etc.

[krusty]

Is it a slow shift on the 1-2 as well as the 2-3? 2-3 in a T700 or 4L60E has the most fluid and parts to shift to release 2nd and apply 3rd so usually the worst of the lot. Also happens to be where torque is best too lol so doesn't make matters any better.

I always overfill the trans by at least 1cm on the dipstick to ensure there's ample fluid. May be something to check before you go re inventing the wheel with trans tuning solutions

[brindo]

Hi,
Both the 1 - 2 and the 2 - 3 changes are slow.. The transmission does have a over 200 000 km on it but the changes were fine before the engine was modified and I am not confident that the slow changes are a result of the extra horsepower. It's not really slipping, just slow to change. I'll add a bit of extra fluid regardless and then try some increased pressures and see what happens.

I am sure a full rebuild along with a shift kit will be needed at some stage in the near future but I would like to get the transmission settings sorted before that happens.

When I originally bought the VT over 10 years ago I had one of DR Bobs memcals installed. This memcal was to of had the Torque Management altered. I think at the time it was referred to the Take the Fun Out Factor and he said it was there to prevent wheel spin on shift changes in the wet. I have no idea what was actually changed and think that memcal has gone to a better place.

Thanks

[krusty]

I wonder if the much larger throttle body has anything to do with TPS values relating to shift parameters. Maybe have a play with your part throttle shift parameters vs line pressure there

[The1]

if youve changed throttlebodies you will need to recalibrate the range 0-100% via the scalar TPS - Throttle Gain %

[brindo]

Hi,
I had already changed that scalar so that at WOT the TPS value is reading about 99 to 100%. If I change this so that it reads a lower % value, will it cause problems in other areas?

Thanks

[The1]

get it to read 100% then go up one increment. That's all ive ever needed to do with larger throttlebodies and the trans works as it did before. usually they around 0.55 - 0.57

[The1]

also try increasing the shift pressure, scalars are "Force Motor - Pressure Added for 1-2 Upshift" try 7psi also do it for 2-3 and 3-4

Also if you havn't got atleast a corvette servo and with more power will make a quicker demise of the trans especially with that km on it.

[delcowizzid]

the throttlebody is the biggest issue anything but full throttle will be out of wack.anything from 3/4-full throttle will probably react the same from the extra throttle position not letting in anymore air