Trans changes

[James Morse]

What year did auto trans go from 4 to 5 or am I mixed up? I'm only talking about years '01 up.
I think mine is 4 forward (3 plus OD) and one reverse. Does that count as 5?
I assume if they say 5-speed auto that means 5 forward gears, but I could be fos, I just don't know.

 

[RonD]

The transmission was always only 4-speeds, 4R or 5R
Ford added a 5th gear in the computer control system

1st gear ratio(2.47) and 2nd gear ratio(1.47) were a full 1 ratio apart in the A4LD and 4R transmissions, which meant the engine needed to REV high in 1st so it didn't bog down when shifting to 2nd

4R has an OD on/off solenoid, OD is 0.75 ratio
So software was added to the computers to turn OD on while still in 1st, this gives a combined ratio of 1.86, so a smoother shift, less REVing, and a "new" 2nd gear ratio, so the 4-speed was now a 5-speed
So old 2nd gear became "3rd" and old 3rd became "4th", and of course OD is now "5th"

A4LD and 4R have these ratios
1st: 2.47
2nd: 1.47
3rd: 1.00
4th: 0.75

5R has these ratios
1st: 2.47
2nd: 1.86(2.47 x 0.75 = 1.8525)
3rd: 1.47
4th: 1.00
5th: 0.75

Very clever these Americans, lol

The 4.0l Rangers got the 5R in 1997/98
4cyl and 3.0l Rangers in 2001
BUT............in 2001 all Rangers got the 5Rs with new sensors added, OSS and ISS which are required for all 2001 and up Ranger computers

If you put a 2002 3.0l 5R trans in a 1998 3.0l it would work, but only as a 4-speed, because 1998 computer software doesn't have the OD on in 1st shifting

 

[ekrampitzjr]

Thanks for the info, RonD.

At least when someone here discusses a tranny, they aren't talking about a person.

 

[JoshT]

The transmission was always only 4-speeds, 4R or 5R
Ford added a 5th gear in the computer control system

1st gear ratio(2.47) and 2nd gear ratio(1.47) were a full 1 ratio apart in the A4LD and 4R transmissions, which meant the engine needed to REV high in 1st so it didn't bog down when shifting to 2nd

4R has an OD on/off solenoid, OD is 0.75 ratio
So software was added to the computers to turn OD on while still in 1st, this gives a combined ratio of 1.86, so a smoother shift, less REVing, and a "new" 2nd gear ratio, so the 4-speed was now a 5-speed
So old 2nd gear became "3rd" and old 3rd became "4th", and of course OD is now "5th"

A4LD and 4R have these ratios
1st: 2.47
2nd: 1.47
3rd: 1.00
4th: 0.75

5R has these ratios
1st: 2.47
2nd: 1.86(2.47 x 0.75 = 1.8525)
3rd: 1.47
4th: 1.00
5th: 0.75

Very clever these Americans, lol

The 4.0l Rangers got the 5R in 1997/98
4cyl and 3.0l Rangers in 2001
BUT............in 2001 all Rangers got the 5Rs with new sensors added, OSS and ISS which are required for all 2001 and up Ranger computers

If you put a 2002 3.0l 5R trans in a 1998 3.0l it would work, but only as a 4-speed, because 1998 computer software doesn't have the OD on in 1st shifting

Well if we want to get technical, wouldn't they all have been 3 speeds.

Essentially the C3 (an old Ford 3 speed auto) became the A4LD by adding a lockup torque converter and an overdrive that was engaged with 3rd to give the .75 overdrive ratio. The A4LD was turned into the 4R by applying electric solenoids to control the transmission. That was turned into the 5R by using the computer to apply overdrive to first gear.

If we're going to say that second in the 5r isn't really a gear, then neither is OD on the A4LD and 4R.

Other than that I agree with everything that Ron posted.

 

[RonD]

Well in fairness the C3 didn't have an OD brake Drum or band, so parts were added to change the 3-speed into a 4-speed, but not the case in changing the 4-speed into a 5-speed

 

[James Morse]

What is the purpose of adding OSS/ISS if the trannies were working perfectly fine without it? Which they seem to do (work well) based on my limited experience with one truck.

 

[RonD]

OSS(output shaft speed) sensor was added to replace the gear driven VSS(vehicle speed sensor) which was remove from transmission/transfer case in 1998 Rangers
Rangers used the rear axle ABS sensor for speed in 1998-2000 via GEM module calibration

ISS(intermediate shaft speed) sensor................?? need to ask Ford engineers on this one, lol, but I would assume it would detect slipping in clutches or bands(brakes)

 

[JoshT]

Basically added for the same reason as the electronics, to allow finer control over transmission shift points. That allowed them to increase rated efficiency and probably also increase the strength of the transmission on paper.

 

[James Morse]

isn't ISS input shaft sensor?
thanks for info it's really interesting

 

[RonD]

Originally yes, ISS sensor was that but was in a different location, front of transmission, and was never used
The TSS sensor has input shaft speed, as do engine RPMs, comparing the 2 tells computer when torque converter locks up
These would be codes for TSS
P0715 Input/Turbine Speed Sensor Circuit Malfunction
P0716 Input/Turbine Speed Sensor Circuit Range/Performance
P0717 Input/Turbine Speed Sensor Circuit No Signal
P0718 Input/Turbine Speed Sensor Circuit Intermittent

New ISS sensor is located mid-transmission, above shifter rod/lever
It has codes starting at P0791 Intermediate Shaft Speed Sensor Circuit Malfunction
Then P0792 and P0793

 

[85_Ranger4x4]

What is the purpose of adding OSS/ISS if the trannies were working perfectly fine without it? Which they seem to do (work well) based on my limited experience with one truck.

After the C5 Ranger automatics always had room for durability improvement, they did get better as time went on.

 

[James Morse]

@RonD If the original ISS sensor was never used, why was it even there? How else would trans know when to lock up?

 

[RonD]

Because they already had the TSS sensor and the engine's RPM to detect lockup or lack of it

I think it was only there for 2 or 3 years on the first 5R55E models, not 4R, 1997-1999 castings

Had the hole up by bell housing, seen here: https://www.explorerforum.com/forums/attachments/img_20160415_174052923-jpg.309083/

Ford's recommendation when when there was no hole for sensor, so no plug in for its 2 wire connector, "cut off the connector, twist wires together, seal the connection", lol

2001 Housing here, with new ISS and OSS holes(red plugs): https://www.transmissionrepaircostg...2018/03/Remanufactured-5R55E-Transmission.jpg

 

[James Morse]

That is just bizarre.
Thank you for the excellent info.