Hard 1>2 Shift

[BowlingSS]

I installed a FLT transmission a few months ago and since then the 1>2 shift is way to hard. After the trans install FLT wanted me to change my trans pressure back to standard, which I did. I also have a 3500 Stall. How can I change it to make it a little softer? I am running COS5. Below is my current tune.

[ChipsByAl]

I am not sure what your base file is, I compared to the 2002 automatic file from HoldenCrazy. Check D4601 for fourth gear, it is out of range. Also with this compare, the force motor and torque reduction are both modified from stock. Do you have a log with the PIDs for trans pressure? Is it possible this S/D tune does not get the torque signal correct and affect the trans pressures.
Al

[BowlingSS]

My base was a 2001 Camaro. Would have to look up the OS. Been running COS5 for years. I had torque reduction turned off with the old trans. I put a little back in per the trany place. I will setup a log for the trans pressures. I do not think I have logged trans pressure before. Do you know what PID's I should select?

Thanks.
Bill

[joecar]

TFMPRS(psi) and TRQENG(ftlb).

[BowlingSS]

Thanks Joe. I will add them for a run in the morning on the way to work.

Bill

[goldbergv95]

With the new stall, set the D2903 to 90 and D2904 to 100.

[BowlingSS]

Here is my log.

Thanks everyone.

Bill

[BowlingSS]

With the new stall, set the D2903 to 90 and D2904 to 100.
What are we setting here? Do not have my notebook with me.

Bill

[joecar]

Bill, try this:
- reduce the 1->2 shift pressure;
- increase the 1->2 shift time;
- increase 1->2 shift torque reduction;

Did you have hard 1->2 shift from the get-go with this trans...? Does it have a shift kit installed...? If so then the 1-2 accumulator spring may be too tight (too many washers/shims installed).

[BowlingSS]

It has been this way since day 1. Not sure about a shift kit. It is a FLT trany. I will give this a try. Thanks Joe.

[InTruckDesign]

After putting a built trans. in my '07 Tahoe I was having the same issue. I ended up increasing shift time alittle, 10% trq reduction on the 1>2, and also set TCC to unlock during shifts.

[BowlingSS]

Bill, try this:
- reduce the 1->2 shift pressure;
- increase the 1->2 shift time;
- increase 1->2 shift torque reduction;

Did you have hard 1->2 shift from the get-go with this trans...? Does it have a shift kit installed...? If so then the 1-2 accumulator spring may be too tight (too many washers/shims installed).

The 1>2 shift pressure- Is this DO701
- increase the 1->2 shift time; D1108
- increase 1->2 shift torque reduction: D0801(mine is set to all 0's.

What should I set the above PID's to? I do not want to mess up my trany.

Thanks Joe.

Bill

[joecar]

Try:
- set D1108 to 0.35s.
- set D0801 to 20%.

Test drive, and then adjust from there.

[BowlingSS]

Try:
- set D1108 to 0.35s.
- set D0801 to 20%.

Test drive, and then adjust from there.

I will find out in the morning how the changes helped.
Thanks.
Bill

[BowlingSS]

Changing D1108 to .35 and D0801 to .20 helped. It is still a little hard but better. I am going to drive it a few days and then change it a little more. I think i will try .38 and .25. What do you think Joe?

Thanks for your help Joe. You da Man.

Bill

[joecar]

Try setting D0801 to 30%.

[BowlingSS]

Try setting D0801 to 30%.

OK I set D0801 to .3. Will test drive tomorrow morning on the way to work.
Thanks.
Bill

[BowlingSS]

Changed to .30. Can I change it even more? It is still shifting hard. Better but still hard.

[joecar]

Yes, you can go even higher.

[BowlingSS]

Yes, you can go even higher.

I think I will try .35 after I fix the over heating problem that just started on my way home yesterday. I think the thermostat is bad. Going to replace it in the morning. it is much cooler now in the mornings.
Thanks Joe.

[joecar]

Try 50%.

[drdarthinvader]

D4602 will progressively apply clutch pressure to soften shifts ive set these to disable and adjusted pressures as in previous posts.this can give a (smooth then hard shift)shift

[joecar]

I don't have D4602 in my file.

[drdarthinvader]

I don't have D4602 in my file.

d4602 is in trans cal>general>shift stabilization enabled

[Taz]

D4602 is not an available parameter for this particular application.


Regards,
Taz