Magnus

iTrader: (4)

I've seen several posts here recently concerning the holding power for 3'rd vs the D selection for the 4L60E.. What I read that was most important to me is that 3'rd is used for towing and such and offers more holding power for the 3'rd gear clutch.

My concern is should I race in 3'rd or 4'th.. If there is more holding power in 3'rd, then 3'rd it is for me..

But as many of us know, the trans shifts later on the 2-3 if we keep it in 3'd as opposed to D.

If 3'rd will help provide more holding power and increase transmission life, then I think it may be best to tune the shift points for a 3'rd gear selector on the 2-3 shift vs a D selection on the 2-3 shift.

So what is everyones thoughts on this?

Colonel

My opinion is that there is more slippage on the 2-3 shift when the selector is in 3rd. Others believe that the shift just takes longer to be initiated with it in 4th. Maybe it's a comination of the two.

I always race in 4th.

RPM WS6

iTrader: (3)

I'd like to see some more opinions on this as well. I've heard confilcting stories myself...

Kent1

My car runs a about half of a tenth faster in 3rd in stock form without heads and cam---why I don't know. But for me, the results speak for themselves. I would experiment at the track both ways and go with the optium procedure. Cheers......

Magnus

iTrader: (4)

Kent1, it could be beacuse your car is holding out the 2-3 shift a little longer in the 3'rd gear selection vs the 4'th gear selection.

3'rd gear selection usually results in a later 2-3 shift than the 4'th gear selection.

Colonel, if you believe there is more splippage on the 2-3 when in the 4'th selection, why do you race in 4'th then? (if you don't need 4'th gear in the 1/4)

Ragtop 99

iTrader: (7)

My car shifts more accurately in OD then in D so that's how I race.

Pete2k_Z28

I agree. Although the 1-2 shift is firmer, the 2-3 shift never executes cleanly. Usually results in a journey to the rev limiter momentarely. No good on the spray. So I just run OD.

Colonel

"Colonel, if you believe there is more splippage on the 2-3 when in the 4'th selection,"

Sorry, that was a typo. I meant to say more slippage in 3rd. :o

I've been racing (and autotapping while doing so) these trannys for quite awhile. It seems clear to me (at least with all of the 4L60-Es that I've had) that there is more slippage, or "flare up", on the 2-3 shift with the selector in 3rd. That is why I race in 4th.

However, I can see why someone might go a little faster with the selector in 3rd IF their shift points are set a little low. I set mine up to shift properly timed with the selector in 4th. It seems to be more consistant in 4th too.

Magnus

iTrader: (4)

Ok, I agree about the flareup.. but I'm not sure if that is just delayed shift point.. if its shifting at the same time regardless of gear selection 3/4, then it means there is less line pressure in the 3'rd gear selection to engage 3'rd gear in the transmission.

So how does the line pressure and holding power differ between the 3(D) and the 4(OD) selections?

Anyone know the inner workings of the 4L60E that can verify this or add some insight?

SMOKINV8

iTrader: (6)

From the sounds of the shift characteristic differences, it sounds like when the trans is in D, it raises the line pressure for the 1-2 servo at the expense of line pressure for the 2-3 servo. It would make sense if you put it in "towing" terms... If you were towing a large object and were taking off from a stop, it would be more vital to have a crisp 1-2 shift than a 2-3 shift.

Maybe Kevin Steele can pitch in here for a more educated/accurate answer?

TA/30th 1002

I've been away for a while busy with work and honey-doo's

The added holding power is from an extra clutch pack being aplied. All this extra clutch pack does is take the load off the forward sprag.

The Colonel and I got into this OD vs 3rd thing a while back. I got a little confused back in that thread with some of the nonenclature used! ... ie: "Slipping ... Flare-up".

To me slipping is clutches not holding, Flare-up is clutches not being positively applied in a timely manor during a shift.

It would help me if we had a comon language in threads like this.

Sorry Magnus for side tracking your thread ......

I'm back off to work again ....

ttt ...... Ron

Cummins

iTrader: (2)

so if you guys are saying that it shifts firmer from 1-2 in D then OD and shifts from 2-3 firmer in OD then D, what if you started out in D until it shifted to 2nd then move the shifter to OD to have a better 2-3 shift. would that work i havent had any time to try it?