'flare' between 2nd and 3rd
 

92 LSL, trans cooler, quick change shift kit, synthetic fluids

Used trans installed ~26k miles ago. Had break band tightened about 5k after install due to typical loose band symptoms. Now flaring (it's happened three times in past week) from 2nd to third. No problems going from 3rd to 4th, or vice versa. Have been driving it in "3" when in town.

Thoughts?

Thank you!

Re: 'flare' between 2nd and 3rd
 

looking back at my own thread I started about 2.5 years ago it sounds like the band must be coming loose again. We'll see how tightening it works this time...

Re: 'flare' between 2nd and 3rd
 

Most likely a bad high clutch. An ECUtune TCU would have prevented this failure but it can't fix it.

Re: 'flare' between 2nd and 3rd
 

You might call around to see if you can find a local shop that will replace only your high clutch. That is a lot less labor for them than asking them to rebuild your transmission. I would also show up with OE gaskets (pump gasket and extension housing gasket) and crush washers in hand so when they put it back to together it seals up nice. (they don't even have to take the pan off to do it this way)

Re: 'flare' between 2nd and 3rd
 

the high clutch is fine, it shifts flawlessly from 3-4 and back again when i step on it. The brake band was adjusted again and it seems fine now. I'm sure I don't have many adjustments left in the band but it sounds like it may last another 10-20k...hopefully.

Re: 'flare' between 2nd and 3rd
 

The application of the brake band engages 2nd and 4th not 3rd. If the transmission flares ( A "flare" is when the rpms go up but the vehicle speed doesn't increase--ie slipping of a clutch or band. ) going into 3rd it isn't because of the brake band being loose--that is when the brake band is being released. For 3rd gear the brake band is being released and the high clutch is being applied. A flare going into 3rd gear is the high clutch slipping.

A burnt high clutch can be replaced inexpensively if handled the way I suggested to you. If you continue driving with a bad high clutch you might loose your entire transmission--then again you might just loose 3rd and 4th gear and get another chance at getting only the high clutch and brake band (at that point the heat from the bad high clutch will 100% definitely have taken out the brake band as well). I just want you to understand that you are driving on a bad high clutch. There isn't any doubt about that.

Re: 'flare' between 2nd and 3rd
 

I have always had a "flare" between 2nd and 3rd. It only happens when accelerating very slowly (throttle somewhat closed). When accelerating normally it shifts fine. I've often wondered if there is something wrong. What do you think?

Thanks, Mike

Re: 'flare' between 2nd and 3rd
 

this happens to be between 1st and 2nd, and only at low speeds, and only when the throttle is barely pressed down. i've eliminated it by simply driving in 2nd when i'm in traffic. when the throttle is pressed a little bit more it doesn't do this. it's been doing it since i bought the car 2 years ago, and hasn't got any worse. it's almost like it's confused as to which gear to go in

Re: 'flare' between 2nd and 3rd
 

Well if that's the case I'm guessing it was jesus who allowed me 25,000 miles without a flare AFTER my brake band was adjusted. I think this was explained more concisely by Harvey in the original thread I posted at that time.

Anyway....i'm going to buy another car and stop worrying about this f'ing transmission for awhile.

Re: 'flare' between 2nd and 3rd
 

That's a worn brake band that needs to be tightened.

Re: 'flare' between 2nd and 3rd
 

I don't believe that your trouble is the high clutch. If the high clutch was slipping, you would feel it in 3rd and 4th. If the band was slipping, you would feel it in 2nd and 4th.
As it is 'Flaring' between 2nd and 3rd, the band is releasing before the high clutch applies. This is normally controlled by the hydraulics,changing pressure from the band release servo to the high clutch piston.
This flair is a mechanical fault due to the band having too much clearance on the drum, to let go before the hydraulics have engaged the high clutch.

Harvey.

Re: 'flare' between 2nd and 3rd
 

I'm sorry you feel that way. You could get this fixed inexpensively and enjoy a flawlessly functioning transmission. After that with a simple modification you could drive it without a worry in the world confident it will never fail again. There's no reason for people to live in fear of their SVX transmission.

Re: 'flare' between 2nd and 3rd
 

That sounds like your line pressure is low at that time. You probably just need to adjust your throttle position sensor.

If the adjustment of the brake band allows it to be fully applied by the servo at one throttle position it allows it to be fully applied at any throttle position. You just have more hydraulic pressure available to hold it at different throttle positions.

Line pressure is specified by a value looked up in a map in the TCU according to throttle position. The maps aren't smooth at low throttle positions. A little difference in throttle position can make a big difference in line pressure or barely any difference at all depending on just where you happen to fall on the map. Here is a graph of one of the maps controling line pressure: http://www.ecutune.com/images/3rd&4thDutyControl.gif You can see at 6% throttle (15/255) the solenoid has a 60% duty cycle ((20000-8000)/20000) bleeding off most of the line pressure. At just a little more throttle the map jumps up to 30% duty cycle ((20000-14000)/20000) that's half as much bleed off of line pressure. A missadjusted throttle position can have you sitting just on the wrong side of one of these cliffs.

There are other possibilities like the line pressure on your transmission might just be a little low. It's also possible your brake band is just out of adjustment enough that it can barely tighten at high line pressure and low line pressure isn't enough to quite get it there but that is stretching it--excuse the pun.

It is important that the brake band be in propper adjustment but once it is it usually stays that way. The travel on your brake band servo, that's the piston that open and closes the brake band around the reverse drum, is very long. The lining on your brake band is very thin. There are always exceptions around the margins but in general if the band wears enough to need adjustment it needs replacement. They always wear the most at the ends where it is sinched together by the servo application. The hardware on the band is riveted here so there are rivets which start digging into your reverse drum as soon as the band is this worn. From there the friction material starts flaking away from the ends so you have an increasing amount of metal on metal contact. The brake band will keep functioning like this but it will behave more erratically and is destroying the reverse drum.

Re: 'flare' between 2nd and 3rd
 

Your flare is most likely for the same reason as I described to B4. In your case it's the high clutch slipping but

still since it only slips at low throttle it is likely because your line pressure is a little low at low throttle. You

should check your TPS.

Your line pressure might also just be a little low. There is also a greater chance of wear being the culprit when the

high clutch slips than there is when the brake band slips. The high clutch is a stack of "frictions" and "steels." A

friction is a steel plate with friction material bonded to it's faces and splines towards the inside. A steel is a

plain steel plate which splines towards the outside. The frictions and steels are stacked inside of a clutch drum

(clutch drum = outer rotating member) organized as: friction, steel, friction, steel, friction, steel....The pack is

finished off with a retaining plate and a big snap ring at the end. Inside of the drum is a piston. When hydraulic

fluid applies pressure to the piston it squeezes the stack together so that the friction between the frictions and

steels locks them together thus locking the hub (hub = inner member which frictions are splined into) to the drum. Here

is a picture of most of the parts I used in one of my first transmission builds:

http://www.ecutune.com/posts/4eat/DSC_3910.jpg I changed a few parts and left a few parts out to miss-direct someone in

particular who was trying to copy what I was doing but it still illustrates the friction materials so you can visually

see and understand what I'm describing. That band on the top right is the brake band. It's a steel band with hardware

riveted to the outside of the ends and then lined with friction material on the inside. As you can see there isn't a

lot of friction material to wear off there--particularly since the majority of wear occurs at the ends as I described

earlier. If it was adjusted right to begin with and then becomes worn enough to need readjustment then there is metal

on metal contact already--at least at the rivets. Directly below it in the picture are the high clutch frictions and

directly below them are the high clutch steels. Failing high clutches don't wear evenly either. First one or two

frictions start falling apart. This creates steel on steel contact. Of course steel on steel contact has friction as

well. As things get worse the steel will start micro-welding together during applicatin and breaking apart on release.

So when the clutch is first applied it slips and the transmission flares until it grabs and then the clutch may hold

until it is released again. It may hold great since the parts are micro-welded together. Just like worn breaks you can

get a lot of friction when you apply them but the results are irratic. Of course eventually the pack fails altogether

and you loose 3rd and 4th entirely unless the heat from all that friction case hardens the thrust bearing on the rear

support enough that it crumbles before the clutch completely fails.

In short, if you have a flare at light throttle like you do look to your tps first.
If it's not your TPS check your line pressure. If you have good line pressure or If you have a 2-3 flare under

modertate to heavy throttle fix your high clutch before you drestroy your transmission.

Re: 'flare' between 2nd and 3rd
 

Hello,

By "flaring" do you guys mean a slight increase in rpm and a longish shift or do you mean the rpms increase by a thousand (severe slip)?

My SVX has a 4,444 tranny from a -97 Outback and under light to moderate throttle the 2-3 shift was looongish and the revs inreased maybe by 200 rpm. The engine lost torque for the time the shift took place, which is exactly what is supposed to happen.

I also experienced a "brake" effect when the transmission shifted 2-3 going down hill with the throttle closed. The revs increased by several hundred (from off idle), well above 1000rpm and the car slowed down for the shift.

I figured the brake band was too tight and eased if out half a turn.

This made a big difference, the 1-2 shift is not as harsh as it used to, there's practically no "brake" effect during 2-3 with throttle closed (maybe just a tad when cold) and the 2-3 under load shift takes only half the time from what it used to. No increase in rpm and also 3-4 is fine even under full boost. Went only for a short spin tonight, will drive more tomorrow and maybe will try an other 1/4 of turn.

Can't wait for the chip, TCU and valve body to arrive from Micheal :).

Regards from Finland,

Tapani