chargedvx6

I have just installed this kit to my car with good results but it is lacking on the 2-3 shift in comparison with the 1-2 shift.

I fitted Fairbanks Billet int & od servos with only the one return spring, alloy oe 2nd accum with 1 shim, pinless foward accum and got a new seperator plate which is what my question is about....

1-2 shift is great, a little firm when the family is in the car but perfect when I am hammering away so can I take the shim out to make it softer off the gas and still get a good hard WOT shift courtesy of the servos?

2-3 leaves alot to be desired however. Doesn't have the same push when shifting 2-3 (o.k but not convincing) and I want to know if this can be adjusted by altering the seperator plate drill point sizes or if there is another way to adjust for a firmer 2-3 shift. The 1-2 shift hole is drilled at 0.082 (short with option of 0.093 full race) and the 2-3 shift hole is drilled at 0.093 whereas it gives an option of 0.101 to suit hi-stall or full race.

I have also read of people using much larger hole sizes 0.17? etc. Is this safe on an otherwise stock transmission?

My car is an L67 (s/c V6) Australian rwd Commodore running 14sec 1/4mile.

Any advice is much appreciated on this one

Gilbert@Ace Racing

It is not safe nor too wise to drill the holes in the seperator plate in the interest of a better "feeling" shift. What we feel and interpret as good is sometimes bad!

It is highly possible to go too far and literally blow the snap ring that holds the 3/4 clutches right out of the drum because of too much pressure. We see that from time to time.

What you are looking for is a quick and firm shift, not an abusive or harsh shift.

The Fairbanks servo is about as agressive as they come. It will be the reason the 1/2 shift is feeling firm when the car is loaded with the crew.

WHat converter is in the car?

Did you install the complete kit or just a few of the pieces?

g

chargedvx6

Yeah as far as the drill holes go I drilled them to the most conservative specs that Trango recommended. Not too sure what their specific purpose is but would rather play it safe on this one, at least until I find out alot more about how this works.

The stock convertor is in the car. It is a 2300rpm unit, not sure on the diameter though, would this justify going to the larger holes in the seperator plate or are they purely for a built box only?

For the transgo kit (HD-2 C) I installed all the components that can be fitted with the tranny in the car except for the servo shims and springs because the servos delete the cusion springs and use just one return spring. Probably why I can't at any time get a softish shift on 1-2.

I guess the question remains, 1: What effect would reducing or adding shims to the 2nd accumulator have?

2: Can I drill to the larger sep plate hole spec due to having a FI stall speed on the convertor and if so, what are the benefits/ negatives of this?

Thanks for ur time G

performabuilt

iTrader: (25)

I would go to the max spec transgo list for the 3-4 clutch , However at the same time I would remove any shims from the 1-2 accumulator and return it to the stock configuration, I think with the fairbanks billet servo and that you will ge what your looking for moderatly firm but progressive on the 1-2 and much firmer on the 2-3 , Now others may have a different opinion and it is true that if you allready have excessive 3-4 clutch clearance increasing the volume and rate of apply could result in damage , But assuming that the 3-4 clutch is in good shape and you have not also electronically altered the presures. I think you will be happy with this combination. IMO

PBA

With the Fairbanks servo, the 1-2 will be firm at almost any throttle openings. Leave the hole at .082 with the stock diameter torque converter. DO NOT add any spacers. The 2-3 hole can be opened to .110 max, this will improve the 2-3 shift at WOT. I would not go larger than this. I do not like the Fairbanks 1-2 servo, for the reasons you stated. I use the Sonnax here in very high HP applications, offers a better part throttle shift. The Corvette servo would have been a better choice here (and is more than enough for what you have), as it would give you smoother part throttle shifts, while still giving you a firm WOT 1-2 shift. For durability, a quick shift is all that is really needed. Too firm of a shift is detrimental to the life of the transmission, especially at part throttle.

chargedvx6

So if I remove the shim from the 2nd accumulator and further enlarge the 3-4 hole to 0.101 that should soften the 1-2 shift at low rpm shifts a little and improve the 2-3 shift?

The tuner won't up the line pressure through the BCM, he does alot of custom combo tunes and is pretty good at feeling his way. Any advice about which shift parameters to stay away from in the tune with this kit fitted would be a help.

Thanks again, wish I had found this forum before I fitted the kit and bought these all out servos, not to worry, the box will be built 2009 and then it can be maxed out hopefully.

Any more tips?

PBA

So if I remove the shim from the 2nd accumulator and further enlarge the 2-3 hole to 0.101 that should soften the 1-2 shift at low rpm shifts a little and improve the 2-3 shift? Yes.
As for "shift firmness", leave the computer tables at zero.

performabuilt

iTrader: (25)

Agreed on leaving the presure table stock , And yes changing it to that set up will likley give you what your looking for

chargedvx6

O.k. I will have a day off next week and will get done according to your guys advice. Cheers.

I still don't understand the function of the accumulators and their relation to shift harshness. Any info or links would be good.

chargedvx6

O.K., I took the valve body out today and did these mods to try and soften the low revs 1-2 shift and firm the WOT 2-3 shift.;

I drilled the 1-2 hole in the sep plate to 0.93, the 2-3 hole to 0.101 and fitted a Sonnax pinless accumulator on the 3-4 accumulator too. Also removed the shim from the 1-2 accumulator but retained the spring either side of the piston configuration that the transgo kit suggest. Also swapped the red spring to the white one on the 2nd accumulator bushing.

So my kit is HD2-C with all Sonnax pinless accumulators and foward piston except the 1-2 which is an OEM style pinned with the longer pin runner. Fairbanks billet servos and I modded the 0.500 boost valve further with an extra feed or release hole, can't remember which it is, the little one at the closed end of the sleeve.

This set up has got it perfect. 1-2 only chirps over 3500rpm but doesn't bump below that, 2-3 is firm and quick and kick downs are really quick and accurate.

The only problem now is to get the T/C lockup set in the tune because of its' on/ off style now instead of slipping to lock up.

Thanks to all the help from the pros and fellow DIY types too, it has been priceless.

PBA

I would have drilled the 1-2 to .086" with the Fairbanks 2nd gear servo on the street, but as long as you like the way it shifts, that is what counts.

chargedvx6

Yeah, I take ur point but my engine has less power than ur guys combos (L67 M90 V6 in a rear wheel drive config) so the shifting is spot on.

I think when I get abit more power the 2-3 shift might wear the clutches too much but a rebuild is on the cards one day anyways so will just enjoy it until then. I only drive the car once or twice a week.

PBA

Did I miss something here, I was talking about the 1-2 shift? Is the 2-3 shift working ok? Are you happy with the 2-3 shift?

chargedvx6

Yeah, I removed the shims on the 1-2 accumulator and drilled the plate to 0.093 on the 1-2 shift hole and 0.109 for the 2-3 shift.

1-2 is good at low revs shifting now and 2-3 shifts firmer than b4. My comment about longevity of the clutches is because I have heard they are a weakpoint of the 4L60E. Time will tell