727 front clutch # springs vs front clutch restrictor size
#3061577
07/22/22 10:21 AM
07/22/22 10:21 AM
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Joined: Dec 2021
Posts: 1,144 Loudoun County, VA
Brad_Haak
OP
super stock
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OP
super stock
Joined: Dec 2021
Posts: 1,144
Loudoun County, VA
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727 front clutch # springs vs front clutch restrictor size? My trans as built has 12 springs in the front clutch setup, but the RMVB I have for it recommends 15. I'm not clear on the relationship between how the number of springs affects the 2-3 shift overlap vs the use of (or not using) a restrictor in the front clutch apply passage. The RMVB is supposed to not require any restrictor, FWIW. Maybe it's a dumba$$ question, but I'll own it. EDIT: It's got a 4.2 lever
Last edited by Brad_Haak; 07/22/22 11:44 AM.
2021 Challenger 6.4L Scat Pack 1320 100% stock: 1.680, 11.894 at 113.75 (DA 175 ft) weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008] pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: Brad_Haak]
#3061645
07/22/22 02:52 PM
07/22/22 02:52 PM
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Joined: Jan 2003
Posts: 25,858 Rio Linda, CA
John_Kunkel
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Rio Linda, CA
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The RMVB is supposed to not require any restrictor, FWIW. The restrictor doesn't have to be in the case, it can be within the VB separator plate.
The INTERNET, the MISinformation superhighway
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: Brad_Haak]
#3061702
07/22/22 08:02 PM
07/22/22 08:02 PM
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Joined: Jan 2003
Posts: 12,153 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
Joined: Jan 2003
Posts: 12,153
Benton, IL.
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I use Dorman #555-115 3/8" mini freeze plugs. Dorman calls them cup expansion plugs. Press one into the passage with a .090" hole and go from there. .090" is usually too small and allows a flair up. But is a good starting point. It usually ends up close to .100". When I am lazy I just put grease on the next size drill bit and drill it in place if it needs opened up. Of course the better way is to screw a sheet metal screw into the restriction and pull it out with a claw hammer.
Be sure to check the shift at the temp that you usually run because the fluid temp can affect the amount of flair or overlap. It is hard to get perfect through a variety of temps. You may have to make a choice towards a slight flair of slight overlap.
Master, again and still
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: DaveRS23]
#3061789
07/23/22 09:12 AM
07/23/22 09:12 AM
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Joined: Dec 2021
Posts: 1,144 Loudoun County, VA
Brad_Haak
OP
super stock
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OP
super stock
Joined: Dec 2021
Posts: 1,144
Loudoun County, VA
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I did a good bit of reading up on the relationship between line pressure, kickdown lever ratio, number of springs in front clutch, and restricting the front clutch apply circuit. I am pleased to say that I am less ignorant today than I was yesterday.
2021 Challenger 6.4L Scat Pack 1320 100% stock: 1.680, 11.894 at 113.75 (DA 175 ft) weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008] pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: Brad_Haak]
#3061838
07/23/22 12:36 PM
07/23/22 12:36 PM
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Joined: Jan 2004
Posts: 8,290 fredericksburg,va
cudaman1969
master
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master
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
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Looking up my other question n another post and saw this. Maybe the reverse valve bodies use these different. But this diagram shows the front clutch only engaged in drive-low? And rear clutch all the time in forward gears. What gives here?
Last edited by cudaman1969; 07/23/22 12:37 PM.
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: cudaman1969]
#3061854
07/23/22 01:48 PM
07/23/22 01:48 PM
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Joined: Jan 2003
Posts: 25,858 Rio Linda, CA
John_Kunkel
Too Many Posts
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Rio Linda, CA
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But this diagram shows the front clutch only engaged in drive-low? And rear clutch all the time in forward gears. What gives here? You're misreading the chart. Drive has three modes, Breakaway (1st gear with no rear band apply), Second and Direct. The front clutch is only engaged in Reverse and Direct. Yes, the rear clutch is applied in all forward gears.
The INTERNET, the MISinformation superhighway
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: cudaman1969]
#3061855
07/23/22 01:49 PM
07/23/22 01:49 PM
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Joined: Dec 2005
Posts: 11,608 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,608
Fulton County, PA
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Looking up my other question n another post and saw this. Maybe the reverse valve bodies use these different. But this diagram shows the front clutch only engaged in drive-low? And rear clutch all the time in forward gears. What gives here? That is correct. Front (direct or high) clutch only applied in reverse and high gear. And to apply the transbrake. Misread the question. The answer is accurate otherwise,
Last edited by CMcAllister; 07/23/22 06:58 PM.
If the results don't match the theory, change the theory.
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: CMcAllister]
#3061859
07/23/22 02:00 PM
07/23/22 02:00 PM
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Joined: Dec 2005
Posts: 11,608 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,608
Fulton County, PA
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Just as with the suspension, springs and the energy stored in them affect how fast things happen. In the past, I've used a balance between the spring load in the front servo and the front clutch to get to 2-3 shift where I wanted it. Mostly in the servo, since it's easier to deal with. Unless it was a transbrake deal. Different deal.
As with most of this stuff, data logging, rather than just listening to it, is invaluable.
If the results don't match the theory, change the theory.
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: John_Kunkel]
#3061883
07/23/22 04:10 PM
07/23/22 04:10 PM
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Joined: Jan 2004
Posts: 8,290 fredericksburg,va
cudaman1969
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master
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
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But this diagram shows the front clutch only engaged in drive-low? And rear clutch all the time in forward gears. What gives here? You're misreading the chart. Drive has three modes, Breakaway (1st gear with no rear band apply), Second and Direct. The front clutch is only engaged in Reverse and Direct. Yes, the rear clutch is applied in all forward gears. Hard to misread ‘disengaged’ right across from drive (breakaway)
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: cudaman1969]
#3062098
07/24/22 02:14 PM
07/24/22 02:14 PM
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Joined: Jan 2003
Posts: 25,858 Rio Linda, CA
John_Kunkel
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Rio Linda, CA
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Like I said, there are three modes in the Drive box. Breakaway (where it's disengaged) is 1st gear, Direct (where it's engaged) is 3rd gear.
The INTERNET, the MISinformation superhighway
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: John_Kunkel]
#3062324
07/25/22 09:51 AM
07/25/22 09:51 AM
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Joined: Jan 2004
Posts: 8,290 fredericksburg,va
cudaman1969
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master
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
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Like I said, there are three modes in the Drive box. Breakaway (where it's disengaged) is 1st gear, Direct (where it's engaged) is 3rd gear. Yep, not used to the term break away.
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: cudaman1969]
#3062393
07/25/22 12:57 PM
07/25/22 12:57 PM
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Joined: Jan 2003
Posts: 25,858 Rio Linda, CA
John_Kunkel
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Too Many Posts
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Posts: 25,858
Rio Linda, CA
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They use the term breakaway to differentiate between 1st gear in Drive and 1st gear in manual low (1). Only difference is the rear band applies in manual low to provide deceleration braking.
The INTERNET, the MISinformation superhighway
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: John_Kunkel]
#3062481
07/25/22 03:38 PM
07/25/22 03:38 PM
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Joined: Sep 2003
Posts: 19,464 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,464
north of coder
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i remember somewhere you could tap the case for 1/8" npt. the hole size in the case was already the size needed for the tap. then use a female hex pipe plug, drill the plug for the restriction size you wanted, then screw in the plug, keeping it slightly below the case surface so the valve body would bolt up flush. anyone ever try this ?
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Re: 727 front clutch # springs vs front clutch restrictor size
[Re: moparx]
#3062556
07/25/22 07:42 PM
07/25/22 07:42 PM
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Joined: Jan 2003
Posts: 12,153 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
Joined: Jan 2003
Posts: 12,153
Benton, IL.
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Check my earlier post for an easier way to make the restriction.
Master, again and still
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