4l80e conversion in 1985 suburban. What parts do I need?

[NickTransmissions]

Installed the transmission and drove the first time today. Either this shift tune is bad, or something else is off. This thing feels like a dog now, shift points are too low and worst of all, this thing shudders like a mother when the converter locks up in 4th gear.

Perform a driving line pressure test. Short shifts and TC shudder is likely low LP across the board, which is probably C3-driven. If LP is low, contact the company that man'ed or sold the controller for tech support, if you havent already done so.

 

[txaggie]

Perform a driving line pressure test. Short shifts and TC shudder is likely low LP across the board, which is probably C3-driven. If LP is low, contact the company that man'ed or sold the controller for tech support, if you havent already done so.

Thanks Nick. It’s a Holley sniper trans controller and all the line pressure looks to be pretty similar.

Perform a driving line pressure test. Short shifts and TC shudder is likely low LP across the board, which is probably C3-driven. If LP is low, contact the company that man'ed or sold the controller for tech support, if you havent already done so.

What is “C3 driven?”

 

[NickTransmissions]

Thanks Nick. It’s a Holley sniper trans controller and all the line pressure looks to be pretty similar.

What is “C3 driven?”

C3= communication, command and control.

What exactly are your line pressures for all range positions at idle and at stall?

 

[txaggie]

C3= communication, command and control.

What exactly are your line pressures for all range positions at idle and at stall?

Found the issue. Shudder is most likely a burnt plug wire and dead cylinder:

 

[txaggie]

Perform a driving line pressure test. Short shifts and TC shudder is likely low LP across the board, which is probably C3-driven. If LP is low, contact the company that man'ed or sold the controller for tech support, if you havent already done so.

C3= communication, command and control.

What exactly are your line pressures for all range positions at idle and at stall?

Nick,

After we got the plug wire fixed, it drives pretty good. However the second gear shift is really hard and others are not. Also, after normal highway driving, this thing heats up to 210 ish with nothing being pulled and I have an extra Derale cooler in junction with our radiator cooler. Does this seem a bit high? The turbo 400 without pulling wouldn’t get above 180-190.

Today is hot though, 98 degrees.

 

[txaggie]

Nick,

After we got the plug wire fixed, it drives pretty good. However the second gear shift is really hard and others are not. Also, after normal highway driving, this thing heats up to 210 ish with nothing being pulled and I have an extra Derale cooler in junction with our radiator cooler. Does this seem a bit high? The turbo 400 without pulling wouldn’t get above 180-190.

Today is hot though, 98 degrees.

Just went and drove the crap out of it. Trans temp warmed up to 205 and then cooled back to 198.

I’ll take this to my buddy this next week and get it tuned (engine and trans).