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Discussion Starter · #1 ·
I've had the Sonnax plug and play line pressure booster on my 04 QC for over a month, and from the driver's seat I give it a x2
inexpensive mod!
Noticeably firmer shifts at WOT, and after a few miles of city and interstate driving, I've noticed firmer shifting at part throttle. No codes and all the tranny lines are dry, so no issues with the increased pressure.
My mods are a CAI and exhaust with SC3815/87 performance tune, and I won't be damned if I got a second gear scratch out of that old heavy girl on a spirited drive down the on ramp. It was her first
.
It will be an interesting drive when I get around to getting a SC3865 and can program the shifting.


http://www.sonnax.com/announcements/44957-LB1_LB2.pdf
 

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Stu
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Please keep us posted if you have any problems that could be related with the line pressure booster. I plan on doing that mod too. Thanks CavRam.
 

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Discussion Starter · #4 ·
Still have the Sonnax line pressure booster hooked up in-line with the Trans electronic controls and I have had no negative issues. Just completed a move from northern WA to southern CA traveling through mountain passes with a fully loaded bed and towing my wife's car on an auto hauler. Shifts were firm and flawless with no overheating or trans codes. Still a definite recommendation as an inexpensive mod.
 

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Where can I get one?
What's the cost?
Where does it install?
 

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Did you buy the 10-15psi or the 15-30psi?
 

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Stu
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I installed one a few weeks ago. My trans was slipping and chattering in third gear bad under boost at WOT. The Sonnex line pressure booster has helped allot. It still slips in third gear but, only half as bad.
It chatters only a little now. The trans also feels like it has a better pull, 1st to 2nd to 3rd gears.
Yes, I will be changing the trans. But, it make me think. Could this line pressure booster have saved my trans in the first place.... Hummmmm....... The Sonnex line pressure booster is money well spent. Let's face the facts. Our transmissions aren't as strong as they should be. Some thing to think about.
 

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Originally posted by Ghost03hemi:
I installed one a few weeks ago. My trans was slipping and chattering in third gear bad under boost at WOT. The Sonnex line pressure booster has helped allot. It still slips in third gear but, only half as bad.
It chatters only a little now. The trans also feels like it has a better pull, 1st to 2nd to 3rd gears.
Yes, I will be changing the trans. But, it make me think. Could this line pressure booster have saved my trans in the first place.... Hummmmm....... The Sonnex line pressure booster is money well spent. Let's face the facts. Our transmissions aren't as strong as they should be. Some thing to think about.
What PSI booster did you use?
 

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Board of Directors (Jay)
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and the price is?
 

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What size boost was it? and where did you order it from?
 

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Discussion Starter · #12 ·
Originally posted by befast0rbelast:
Did you buy the 10-15psi or the 15-30psi?
The booster for the 545RFE (LB2), which is on my Hemi, says 15-30 psi increase.
 

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Discussion Starter · #13 ·
Originally posted by befast0rbelast:
What size boost was it? and where did you order it from?
I got mine from transmissioncenter.net for $49. I googled and found one for $39.50.
 

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Awesome thanks!
 

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Originally posted by CavRam:
Originally posted by befast0rbelast:
What size boost was it? and where did you order it from?
I got mine from transmissioncenter.net for $49. I googled and found one for $39.50.
Can you post a link?
I must be a google idiot because nothing is coming up for me!
 

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Thank you!
 

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Yes, I realize no one has posted on this for several months but I wanted to add my two cents. I was at the Chrysler Classic at Summit Motorsports Park and talked to one of the guys at the Mopar Performance booth about transmission upgrades/swaps for the hemi rams. He mentioned that they had a parts/shop truck that one of the engineers tweaked the computer to increase the line pressure and the transmission actually was more efficient (less slip). When I described the Sonnax gizmo, he said that sounds very similar to what the engineer did. Going to be doing this once the weather breaks. Just my two cents.
 
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