Author Topic: torqueflight front clutch springs  (Read 876 times)

Offline BarracudaDave

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torqueflight front clutch springs
« on: January 25, 2019 - 10:43:48 AM »
I'm in the process of rebuilding a 71+ torqueflight for my 340 cuda.  I've used recommendations and experiences posted here as a guide.  During disassembly, I found that my front clutch had only six retainer springs, I was expecting around nine.  I have not found alot of information on how these springs effective transmission operation and whether you should have more or less for a performance application.  FYI, I also plan to install a Transgo TF-2 shift kit.




Offline BarracudaDave

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Re: torqueflight front clutch springs
« Reply #1 on: January 25, 2019 - 10:17:04 PM »
After my post, I found this reply to a similar question posted on Moparchat.  The information was provided by Mr. John Kunkel

 
"The factory used a variety of different spring combos on the same motor in different years and the aftermarket builders won't even agree on the best combo. To add to the confusion, there is a long and short front clutch return spring and their tension is different at installed height. (The short spring is the stiffest) So, ten longs have the same tension as seven shorts, etc.

The theory behind a strong front clutch spring pack is to slow down the engagement of the front clutch during the 2-3 upshift, this should prevent the severe overlap that occurs if the clutch applies firmly before the kickdown band is released. If the clutch engagement is slowed down too much, there will be engine rpm flareup as the band releases and there is no clutch application. One downside to a stiff spring pack is reduced holding pressure at the clutch. Higher pressures can overcome this but higher pressures lead to quicker apply times, a vicious circle.

The front clutch spring pack and clutch clearance should work in concert with the kickdown servo and band lever ratio for the most efficient 2-3 upshift overlap.

Confusing??? You betcha.

My personal preference is to run a fairly loose four disc front clutch pack (.060"-.080") for minimal drag and best lube flow, combined with a medium spring pack of nine short springs. The apply rate of the clutch can then be controlled with a simple orifice restrictor in the front clutch apply passage. Most reprogramming kits supply a small cup soft plug with a drilled orifice that is driven into the passage in the case. I prefer to tap the case 1/8" NPT and install a socket head pipe plug drilled to the appropriate size (I start at .150"), this is easier to remove and change.

The orifice offers the advantage of being easy to change by merely removing the valve body, clutch changes require removal/disassembly of the whole trans."