Dyno'd the Hoe, Carnage pics....
Dec 29, 2007 | 04:25 PM
#81
TECH Addict
Joined: Feb 2004
Posts: 2,120
Likes: 0
5. Scan trans with TranX at trans shop to find out why my 1-2 shift is so harsh.
I was having this problem and I finally dropped my Normal Base Shift Pressure (PSI) vs Torque vs Shift. I dropped the whole 1 -> 2 shift column by 6 psi and it fixed the problem. I will try and raise it some until I figure out the minimum amount I need to drop it to fix the hard shift. I am not sure what torque step it shifts at so I dropped them all. If I figure out what torque step in particular needs to be changed I will let you know.
Break a leg...
I was having this problem and I finally dropped my Normal Base Shift Pressure (PSI) vs Torque vs Shift. I dropped the whole 1 -> 2 shift column by 6 psi and it fixed the problem. I will try and raise it some until I figure out the minimum amount I need to drop it to fix the hard shift. I am not sure what torque step it shifts at so I dropped them all. If I figure out what torque step in particular needs to be changed I will let you know.
Break a leg...
Dec 29, 2007 | 04:39 PM
#82
GFYS and STFU
iTrader: (8)
Joined: Jan 2007
Posts: 13,870
Likes: 4
From: Here and sometimes there too.
Correct!
Here is a quick rundown on the driveshaft incident.
I had my stock shaft shortened and balanced at the advice of a trans shop
They thought the shaft was pushing into the back of the trans.
Found out this was wrong and that it was most likely the pinion angle that was off. After talking to Chuck at FLT I swapped a stock shaft back in. This was because I only had about 1/3 of the splines in contact with the output shaft. The correct length stock shaft was only balanced to stock specs.
At 140mph the stock shaft gave up and you see what happened.
I swapped to a 4L80E and a 3" OD aluminum shaft. I have yet to get the pinion angle checked. Its on my list when I get back from Mortar-rita-ville.
Here is the list:
1. Install new shifter on GTO (already bought)
2. Install wet kit on GTO (already bought)
3. Adjust 4L80E tune for shift points on Tahoe
4. Get pinion angle checked on Tahoe
5. Scan trans with TranX at trans shop to find out why my 1-2 shift is so harsh.
6. Have sex with wife
Maybe not in that order
Here is a quick rundown on the driveshaft incident.
I had my stock shaft shortened and balanced at the advice of a trans shop
They thought the shaft was pushing into the back of the trans.
Found out this was wrong and that it was most likely the pinion angle that was off. After talking to Chuck at FLT I swapped a stock shaft back in. This was because I only had about 1/3 of the splines in contact with the output shaft. The correct length stock shaft was only balanced to stock specs.
At 140mph the stock shaft gave up and you see what happened.
I swapped to a 4L80E and a 3" OD aluminum shaft. I have yet to get the pinion angle checked. Its on my list when I get back from Mortar-rita-ville.
Here is the list:
1. Install new shifter on GTO (already bought)
2. Install wet kit on GTO (already bought)
3. Adjust 4L80E tune for shift points on Tahoe
4. Get pinion angle checked on Tahoe
5. Scan trans with TranX at trans shop to find out why my 1-2 shift is so harsh.
6. Have sex with wife
Maybe not in that order
I'll be flying out to Kuwait on monday...you should cross over the border and come pick my *** up!
I need a tour guide brother!!!
Dec 29, 2007 | 05:05 PM
#83
TECH Senior Member
Joined: Jul 2006
Posts: 7,023
Likes: 0
From: Somewhere around -199C
Correct!
Here is a quick rundown on the driveshaft incident.
I had my stock shaft shortened and balanced at the advice of a trans shop
They thought the shaft was pushing into the back of the trans.
Found out this was wrong and that it was most likely the pinion angle that was off. After talking to Chuck at FLT I swapped a stock shaft back in. This was because I only had about 1/3 of the splines in contact with the output shaft. The correct length stock shaft was only balanced to stock specs.
At 140mph the stock shaft gave up and you see what happened.
I swapped to a 4L80E and a 3" OD aluminum shaft. I have yet to get the pinion angle checked. Its on my list when I get back from Mortar-rita-ville.
Here is the list:
1. Install new shifter on GTO (already bought)
2. Install wet kit on GTO (already bought)
3. Adjust 4L80E tune for shift points on Tahoe
4. Get pinion angle checked on Tahoe
5. Scan trans with TranX at trans shop to find out why my 1-2 shift is so harsh.
6. Have sex with wife
Maybe not in that order
Here is a quick rundown on the driveshaft incident.
I had my stock shaft shortened and balanced at the advice of a trans shop
They thought the shaft was pushing into the back of the trans.
Found out this was wrong and that it was most likely the pinion angle that was off. After talking to Chuck at FLT I swapped a stock shaft back in. This was because I only had about 1/3 of the splines in contact with the output shaft. The correct length stock shaft was only balanced to stock specs.
At 140mph the stock shaft gave up and you see what happened.
I swapped to a 4L80E and a 3" OD aluminum shaft. I have yet to get the pinion angle checked. Its on my list when I get back from Mortar-rita-ville.
Here is the list:
1. Install new shifter on GTO (already bought)
2. Install wet kit on GTO (already bought)
3. Adjust 4L80E tune for shift points on Tahoe
4. Get pinion angle checked on Tahoe
5. Scan trans with TranX at trans shop to find out why my 1-2 shift is so harsh.
6. Have sex with wife
Maybe not in that order
Dec 29, 2007 | 06:39 PM
#84
Thread Starter
Destroyer of Transmissions
iTrader: (28)
Joined: Feb 2005
Posts: 4,962
Likes: 1
From: Orlando, FL
Yea, I had to leave on pretty short notice. I was notified Monday and left Friday morning. 
That was the first week of October. So I'm about 1/2 done.
Id ropped the pressure on the 1-2 shift quite a bit and it didnt help at all. I think whoever put in the shift kit drill the seperator plate as big as possible. The very forst cold shift of the day is perfect. Then they become pretty harsh. Its as if when the fluid is anything above ambient it flows too much fluid and makes the shift too hard. I was dealing with it because I was sick of dealing it. Once I get back I may be in a better mod to rip the trans out and start looking into it.
That was the first week of October. So I'm about 1/2 done.
Id ropped the pressure on the 1-2 shift quite a bit and it didnt help at all. I think whoever put in the shift kit drill the seperator plate as big as possible. The very forst cold shift of the day is perfect. Then they become pretty harsh. Its as if when the fluid is anything above ambient it flows too much fluid and makes the shift too hard. I was dealing with it because I was sick of dealing it. Once I get back I may be in a better mod to rip the trans out and start looking into it.
Dec 29, 2007 | 06:41 PM
#85
Thread Starter
Destroyer of Transmissions
iTrader: (28)
Joined: Feb 2005
Posts: 4,962
Likes: 1
From: Orlando, FL
5. Scan trans with TranX at trans shop to find out why my 1-2 shift is so harsh.
I was having this problem and I finally dropped my Normal Base Shift Pressure (PSI) vs Torque vs Shift. I dropped the whole 1 -> 2 shift column by 6 psi and it fixed the problem. I will try and raise it some until I figure out the minimum amount I need to drop it to fix the hard shift. I am not sure what torque step it shifts at so I dropped them all. If I figure out what torque step in particular needs to be changed I will let you know.
Break a leg...
I was having this problem and I finally dropped my Normal Base Shift Pressure (PSI) vs Torque vs Shift. I dropped the whole 1 -> 2 shift column by 6 psi and it fixed the problem. I will try and raise it some until I figure out the minimum amount I need to drop it to fix the hard shift. I am not sure what torque step it shifts at so I dropped them all. If I figure out what torque step in particular needs to be changed I will let you know.
Break a leg...
Dec 29, 2007 | 06:47 PM
#86
TECH Veteran
Joined: Mar 2004
Posts: 4,632
Likes: 2
From: Sun Diego
Id ropped the pressure on the 1-2 shift quite a bit and it didnt help at all. I think whoever put in the shift kit drill the seperator plate as big as possible. The very forst cold shift of the day is perfect. Then they become pretty harsh. Its as if when the fluid is anything above ambient it flows too much fluid and makes the shift too hard. I was dealing with it because I was sick of dealing it. Once I get back I may be in a better mod to rip the trans out and start looking into it.
Dec 30, 2007 | 05:48 PM
#89
Thread Starter
Destroyer of Transmissions
iTrader: (28)
Joined: Feb 2005
Posts: 4,962
Likes: 1
From: Orlando, FL
Id like to see your TQ vs shift pressure table on the 1-2 shift once you get it the way you want. Also your shift rpm at wot for 1-2. Another member told me he had to set his to shift at 5500 to get it to shift at 5800-6000. Mine was bouncing of the rev limiter or fuel cutoff when I had the shift rpm set to 6000 with fuel cutoff at 6200. I lowered th shift rpm to 5800 and it didnt help. I am going to drop it to 5500 whan I get back and see. Just wondering if this is a 4L80E common issue. I have the shift speeds set to 0 so its not part of the equation.
