Ford’s First Automatic Transmission: The Story Behind the ...
Ford’s 6F50N: Introducing Another 6-Speed LET'S PLAY BALL ... · Ford’s 6F50N: Introducing...
8
18 GEARS December 2008 F ord’s 6F50N is just one more of the 6-speed transaxles being produced today. Ironically, this transmission is very similar to the GM 6T70. So once again, if you know how one of these transmissions operate, you’ll know the other. This article is an introduction to the 6F50N; we’ll cover the internal components and solenoid operation as they pertain to clutch operation. Let’s start with the planetary gearset: Planetary Gearset THE 6F50N has 3 planetary gear- sets to provide operation in reverse and six forward speeds (Figure 1). The gearsets include these com- ponents: • Front planetary sun gear (part of the front sun gear and shell assembly) • Front planetary carrier • Front planetary ring gear • Center planetary sun gear • Center planetary carrier • Center planetary ring gear • Rear planetary ring gear • Rear planetary carrier • Rear planetary sun gear and shell assembly The front planetary sun gear is splined to the forward (1, 2, 3, 4) clutch and is held stationary in 1 st , 2 nd , 3 rd and 4 th gears (Figure 2). The front planetary carrier is splined to the rear planetary ring gear. It transfers power from the rear planetary gearset to the front planetary gearset in 2 nd , 3 rd , 5 th and 6 th and reverse. The front planetary carrier is splined to the transfer shaft drive gear. The front plan- etary carrier is the output component for the planetary gearset. The front planetary ring gear is splined to the center planetary carrier (Figure 3). It transfers power from the center planetary gearset to the front planetary gearset in 1 st , 2 nd , 3 rd and 4 th gears. The center planetary sun gear is splined to the input shaft and is used as input to the planetary gearsets in 1 st , 2 nd , 3 rd and 4 th gears. The center planetary ring gear is splined to the rear planetary carrier. It transfers power from the center plan- etary gearset to the rear planetary gear- set in 3 rd gear, from the rear planetary gearset to the center planetary gearset in 4 th gear. It’s held stationary by the low one-way clutch (OWC) and low/ reverse clutch in 1 st and reverse. The rear planetary carrier is splined to the overdrive (O/D) (4, 5, 6) clutch hub (Figure 4). It transfers power from the input shaft to the rear planetary car- rier in 4 th , 5 th and 6 th gears. The rear planetary sun gear and shell assembly is splined to both the intermediate (2, 6) clutch and the direct (3, 5, R) clutch (Figure 5). The rear planetary sun gear and shell assembly is held stationary by the intermediate (2, 6) clutch in 2 nd and 6 th gears. It’s driven by the direct (3, 5, R) clutch in 3 rd , 5 th and reverse. LET'S PLAY BALL Ford’s 6F50N: Introducing Another 6-Speed by Lance Wiggins Figure 1
Transcript of Ford’s 6F50N: Introducing Another 6-Speed LET'S PLAY BALL ... · Ford’s 6F50N: Introducing...
18 GEARSDecember2008
Ford’s 6F50N: Introducing Another 6-Speed
Ford’s 6F50N is just one more of the 6-speed transaxles being produced today. Ironically, this
transmission is very similar to the GM 6T70. So once again, if you know how one of these transmissions operate, you’ll know the other.
This article is an introduction to the 6F50N; we’ll cover the internal components and solenoid operation as they pertain to clutch operation. Let’s start with the planetary gearset:
Planetary GearsetTHE 6F50N has 3 planetary gear-
sets to provide operation in reverse and six forward speeds (Figure 1).
The gearsets include these com-ponents:
• Front planetary sun gear (part of the front sun gear and shell assembly)
• Front planetary carrier • Front planetary ring gear • Center planetary sun gear • Center planetary carrier • Center planetary ring gear • Rear planetary ring gear • Rear planetary carrier • Rear planetary sun gear and
shell assembly
The front planetary sun gear is splined to the forward (1, 2, 3, 4) clutch and is held stationary in 1st, 2nd, 3rd and 4th gears (Figure 2).
The front planetary carrier is splined to the rear planetary ring gear. It transfers power from the rear planetary gearset to the front planetary gearset in
2nd, 3rd, 5th and 6th and reverse. The front planetary carrier is splined to the transfer shaft drive gear. The front plan-etary carrier is the output component for the planetary gearset.
The front planetary ring gear is splined to the center planetary carrier (Figure 3). It transfers power from the center planetary gearset to the front planetary gearset in 1st, 2nd, 3rd and 4th gears.
The center planetary sun gear is splined to the input shaft and is used as input to the planetary gearsets in 1st, 2nd, 3rd and 4th gears.
The center planetary ring gear is splined to the rear planetary carrier. It transfers power from the center plan-etary gearset to the rear planetary gear-set in 3rd gear, from the rear planetary
gearset to the center planetary gearset in 4th gear. It’s held stationary by the low one-way clutch (OWC) and low/reverse clutch in 1st and reverse.
The rear planetary carrier is splined to the overdrive (O/D) (4, 5, 6) clutch hub (Figure 4). It transfers power from the input shaft to the rear planetary car-rier in 4th, 5th and 6th gears.
The rear planetary sun gear and shell assembly is splined to both the intermediate (2, 6) clutch and the direct (3, 5, R) clutch (Figure 5). The rear planetary sun gear and shell assembly is held stationary by the intermediate (2, 6) clutch in 2nd and 6th gears. It’s driven by the direct (3, 5, R) clutch in 3rd, 5th and reverse.
LET'S PLAY BALL
Ford’s 6F50N: Introducing Another 6-Speed
by Lance Wiggins
Figure 1
GEARS December 2008 19
Input ShaftThe input shaft is part of the direct/overdrive clutch
assembly and is splined to the torque converter turbine and the center planetary sun gear. The input shaft transfers power from the torque converter to the rear planetary gearset through the direct (3, 5, R) and overdrive (4, 5, 6) clutches, and the center planetary sun gear. (Figure 6).
Front Planetary Carrier Hub (Output Hub)
The front planetary carrier hub is splined to the front planetary carrier and the transfer shaft drive gear. This allows torque to be transferred from the planetary gearset to the final drive gearset.
Final Drive GearsetThe final drive consists of a gearset that transfers and
multiplies torque from the planetary gearsets to the differential (Figure 7).
Figure 2 Figure 3
Figure 4 Figure 5
Figure 6
18wiggins1208.indd 1918wiggins1208.indd 19 11/18/08 1:27:47 PM11/18/08 1:27:47 PM
20 GEARS December 2008
Ford’s 6F50N: Introducing Another 6-Speed
The final drive consists of:• Transfer shaft drive gear • Transfer shaft and gear assem-
bly • Differential assembly • Ring gear
The planetary gear set transfers power to the transfer shaft drive gear through the front planetary carrier hub. The transfer shaft drive gear is part of the stator support assembly. The trans-fer shaft drive gear turns the transfer shaft and gear assembly, which multi-plies torque through gear reduction and turns the differential ring gear.
DifferentialThe differential allows the half-
shafts and wheels to rotate at different speeds during cornering and transfers power to the Power Transfer Unit (PTU) for all-wheel drive (AWD) vehicles.
The differential assembly consists of the following components:
• Differential case (part of the final drive carrier)
• Two pinion gears supported by a pinion shaft
• Two side gears supported by the differential case and half-shafts
Direct (3, 5, R) ClutchThe direct clutch is a drive clutch
that transfers power from the direct/overdrive hub and shaft assembly to the rear sun gear. The direct clutch is applied in 3rd, 5th and reverse.
Hydraulic pressure from the regulator valve in the valve body pushes the direct clutch piston against the direct clutch pack to apply the clutch. This causes the input shaft to transfer torque to the rear planetary sun gear.
Overdrive (4, 5, 6) Clutch
The overdrive clutch is a drive clutch that transfers power from the direct/overdrive hub and shaft assembly to the rear planetary carrier. The overdrive clutch is applied in 4th, 5th and 6th gears.
Hydraulic pressure from the regulator valve in the valve body pushes the overdrive clutch piston against the overdrive clutch pack to apply the clutch. This allows the input shaft to
transfer torque to the rear planetary sun gear.
Forward (1, 2, 3, 4) Clutch
The forward clutch is a brake that holds the front sun gear and shell assembly. The forward clutch is applied in 1st, 2nd, 3rd and 4th gears.
Hydraulic pressure from the regulator valve in the valve body pushes the forward clutch piston against the forward clutch pack to apply the clutch. Applying the forward clutch pushes forward clutch pack against the low one-way clutch. This holds the rear sun gear and shell assembly stationary to the transaxle case.
Low/Reverse ClutchThe low/reverse clutch is a brake
that holds the low one-way clutch, which is splined to the rear planetary carrier. The low/reverse clutch is applied in manual low, reverse and 1st gear up to 5 km/h (3 mph).
Hydraulic pressure from the
Figure 7
Figure 9
Figure 8
18wiggins1208.indd 2018wiggins1208.indd 20 11/18/08 1:29:41 PM11/18/08 1:29:41 PM
C M Y CM MY CY CMY K
22 GEARS December 2008
Ford’s 6F50N: Introducing Another 6-Speed
regulator valve, routed through the multiplex shift valve in the valve body, pushes the low/reverse clutch piston against the low/reverse clutch pack to apply the clutch. This holds the rear planetary carrier stationary to the transaxle case.
Intermediate (2, 6) Clutch
The intermediate clutch is a brake that holds the rear sun and shell assembly. The intermediate clutch is applied in 2nd and 6th gears.
Hydraulic pressure from the regulator valve in the valve body pushes the intermediate clutch piston against the intermediate clutch pack to apply the clutch. This holds the rear planetary sun gear stationary to the transaxle case.
Low One-Way Clutch (OWC)
The low one-way clutch is a brake that holds the rear planetary carrier in one direction and allows it to freewheel in the opposite direction. This eliminates engine braking in 1st gear, when the transaxle is in drive. The low one-way clutch is used in 1st gear when the transaxle is in drive.
Filler Tube and Pressure Taps
The transmission fluid filler tube is sealed to the main control cover with an O-ring that’s serviced with the transmission fluid filler tube. The transmission fluid level indicator is sealed to the transmission fluid filler tube with an O-ring that’s serviced with the transmission fluid level indicator.
The line pressure tap plug, transmission fluid drain plug, and the lubrication circuit tap plug have pipe threads and seal when tightened to specification.
Solenoid Operation Chart
Most scan tools will show the solenoids as being “ON” or “OFF”. These solenoid are PWM operated, the scan tool will show “ON” or “OFF” which only means they are either working or not (Figure 8)
Solenoid Hydraulic Circuits
Line pressure from the pump is directed to the individual shift solenoids, TCC and line pressure control (LPC) solenoids by the solenoid regulator valve on the SOL FEED circuit. The solenoids, controlled by the PCM, direct fluid to the valves they control.
Figure 10
Figure 11
Figure 12
18wiggins1208.indd 2218wiggins1208.indd 22 11/14/08 9:54:24 AM11/14/08 9:54:24 AM
5 New Technical ManualsAvailable on CD
When one of these transmissions comes across your bench you will be ready to get them out the door. Whether you need help rebuilding or diagnosing a transmissioning these new ATRA books are made for your shop. To keep up in today’s fast pace world ATRA is now offering these books in cd format. You can
now have these technical manuals at your finger tips.Please mention this ad when placing your order. Place your order before 12pm PST and receive same day shipping.
New ATRA books available only in cd format. Sale ends 12/31/08
Toll Free (800) 428-8489 • Fax (805) 604-2001Email [email protected] • Website www.atrabookstore.com
BUY ALL 5 AND SAVE
OVER $80!
Reg Price: $59.95
Reg Price: $59.95
Reg Price: $59.95
Reg Price: $39.95
Reg Price: $39.95
ALL 5 ON ONECD FOR ONLY $175
ATRA bookstr.indd 23ATRA bookstr.indd 23 11/14/08 4:09:06 PM11/14/08 4:09:06 PM
24 GEARS December 2008
Ford’s 6F50N: Introducing Another 6-Speed
The line pressure control solenoid sends varying pressure to the line pressure regulator valve to control line pressure.
In park, shift solenoid D (SSD) directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit. Shift solenoid E (SSE) directs
pressure to the multiplex shift valve, to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch (Figure 9).
In reverse, shift solenoid D directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic cir-
cuit. Shift solenoid E directs pressure to the multiplex shift valve, to direct regu-lated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch. Shift solenoid B (SSB) directs pressure to the direct (3, 5, R) regulator and boost valves through the SSB SIG hydraulic circuit, to apply the direct (3, 5, R) clutch (Figure 10).
In neutral, shift sole-noid D directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit. SSE directs pressure to the mul-tiplex shift valve, to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch (Figure 11).
In 1st gear, shift solenoid A (SSA) directs pressure to the forward (1, 2, 3, 4) clutch regulator and boost valves through the SSA SIG hydrau-lic circuit, to apply the for-ward (1, 2, 3, 4) clutch. Shift solenoid D directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit only when vehicle speed is below 5 km/h (3 mph). Shift solenoid E directs pressure to the mul-tiplex shift valve to direct regulated pressure from the low/reverse/overdrive (4, 5, 6) regulator valve to the low/reverse clutch only when vehicle speed is below 5 km/h (3 mph) (Figure 12).
In 2nd gear, the forward (1, 2, 3, 4) clutch remains applied. Shift solenoid C
(SSC) directs pressure to the intermedi-ate (2, 6) clutch regulator valve through the SSC SIG hydraulic circuit, to apply the intermediate (2, 6) clutch (Figure 13).
In 3rd gear, the forward (1, 2, 3, 4) clutch remains applied. Shift solenoid C releases pressure to the intermediate (2, 6) clutch regulator valve. Shift sole-
Figure 13
Figure 14
Figure 15
18wiggins1208.indd 2418wiggins1208.indd 24 11/14/08 9:54:40 AM11/14/08 9:54:40 AM
GEARS December 2008 25
noid B directs pressure to the direct (3, 5, R) regulator and boost valves through the SSB SIG hydraulic circuit, to apply the direct (3, 5, R) clutch (Figure 14).
In 4th gear, the for-ward (1, 2, 3, 4) clutch remains applied. Shift sole-noid B releases pressure to the direct (3, 5, R) regula-tor and boost valves. Shift solenoid D directs pressure to the low/reverse/overdrive (4, 5, 6) regulator and boost valves through the SSD SIG hydraulic circuit, to apply the overdrive (4, 5, 6) clutch (Figure 15).
In 5th gear, the over-drive (4, 5, 6) clutch remains applied. Shift solenoid A releases pressure to the for-ward (1, 2, 3, 4) regulator and boost valves. Shift sole-noid B directs pressure to the direct (3, 5, R) regulator and boost valves through the SSB SIG hydraulic circuit, to apply the direct (3, 5, R) clutch (Figure 16).
In 6th gear, the over-drive (4, 5, 6) clutch remains applied. Shift solenoid B releases pressure to the direct (3, 5, R) regulator and boost valves. Shift sole-noid C directs pressure to the intermediate (2, 6) clutch regulator valve through the SSC SIG hydraulic circuit, to apply the intermediate (2, 6) clutch (Figure 17).
The TCC control valve opens the TCC release cir-cuit to exhaust, so the TCC release circuit is not pres-surized when the TCC is applied. When the TCC is released, the TCC solenoid does not apply hydraulic pressure to the TCC con-trol or regulator apply valves (Figure 18).
That’s enough for this issue; next time we’ll dig deeper into the 6F50N, to examine the internal components and valve body, and go over important rebuilding tech-
niques and look for likely problem areas.
Figure 16
Figure 17
Figure 18
18wiggins1208.indd 2518wiggins1208.indd 25 11/14/08 9:54:56 AM11/14/08 9:54:56 AM
