4R100 Gear Ratios and Specs

The 4R100 is Ford's heavy-duty four-speed that sat behind the 5.4L, 6.8L V10 and 7.3L Power Stroke in Super Duty pickups and chassis cabs, E-Series vans and the F-53 motorhome chassis. It grew out of the E4OD, and a lot of the hard parts look alike, but the specs are not all the same and mixing them up costs you a comeback.

This is the reference sheet I want on the bench when one of these is apart: the gear ratios, which clutch does what in each gear, the solenoid pattern, fluid and capacity, clutch clearances and the torque numbers. The core numbers come from the ATSG 4R100 manual and Ford's own 2003 Super Duty owner guide and towing guide (full list under Sources).

Recommended 4R100 parts

If the specs below point you at a rebuild, these are the parts that get replaced most: the master kit, the planetary, and the intermediate sprag behind the classic 2nd gear slip. Secure checkout on site.

4R100 Transmission Master Rebuild Kit w/ Raybestos Frictions

$297.99View part

4R100 Planetary

$236.59View part

4R100 Sprag Clutch 1999-2004

$174.99View part

4R100 gear ratios

ATSG's 4R100 description page lists these ratios, and ATRA's gear ratio chart in GEARS magazine (January/February 2006) gives the same 2.71, 1.54, 1.00, 0.71 and 2.18 reverse. They are the same whether the unit is behind a gas engine or the 7.3L, and they carry over unchanged from the E4OD:

A few things fall out of those numbers. The overall spread, 1st divided by 4th, is about 3.8. That is narrow by modern standards, which is why these trucks feel busy on the highway compared to a six-speed. The 1-2 step is the biggest drop in the box, so the engine falls the most RPM on that shift, and it is the shift that gets loaded hardest when you are pulling a trailer off the line. And reverse at 2.18 is lower than 2nd but well short of 1st, so backing a heavy trailer up a grade puts more load on the reverse clutches than people expect.

How it gets there: ATSG describes the gear train as three simple planetary gearsets with seven friction apply elements and three one-way clutches, behind a four-element converter with a converter clutch. The front set is the overdrive planetary. In 1st through 3rd, the overdrive roller clutch locks that set so it passes power through at 1:1, and the rear two sets make 2.71, 1.54 and 1.00. In 4th, the overdrive clutch applies and the overdrive set turns the output faster than the input, which is where the 0.71 comes from.

Clutch and band application chart

This is the chart from ATSG, trimmed to what matters for diagnosis. "Hold" means a one-way clutch is holding.

Read it as a diagnostic tool. Drive 1st uses only the forward clutch. 2nd in Drive depends on the intermediate clutch and the intermediate sprag holding, which is why a worn sprag shows up as a 2nd gear slip or no 2nd. ATRA's 2003 Ford seminar book calls out exactly that on the 4R100: the common cause of 2nd slipping is the durability of the intermediate diode sprag, and it lists the sprag (E9TZ-7A089-B) and clutch plates (1C3Z-7B164-BA), noting the updated drum may also need a new piston and return spring. Manual 1st and Reverse both use the low/reverse clutch, and the coast clutch is what gives you engine braking in manual ranges and with overdrive cancelled.

Solenoid pattern

ATSG lists five solenoids in the pack: shift solenoids SS1 and SS2, the coast clutch solenoid (CCS), the converter clutch solenoid (TCC), and electronic pressure control (EPC). EPC modulates at all times, with the PCM setting line pressure from throttle position, load and vehicle speed.

The TCC solenoid can be on in any forward gear except manual 1st when the PCM decides conditions are right, and on PWM units it modulates the apply rather than switching hard on. When a truck is stuck in one gear, compare the gear it is in to this chart before you condemn the solenoid pack. A unit sitting in 4th with both shift solenoids reading off looks exactly like a lost solenoid feed.

What the ratios mean at the axle

The transmission ratio times the axle ratio is what the tires see. Ford's 2003 RV and Trailer Towing Guide lists F-250/350 Super Duty pickups with the 5.4L on 3.73 or 4.10 axles, the 6.8L V10 on 3.73 or 4.30, and the 7.3L on 3.73 or 4.10. The 7.3L's rating with the automatic is 250 hp and 525 lb-ft. Here are the overall ratios for those axles:

Those axle choices change the tow ratings a lot. In the same Ford guide, a 5.4L Super Duty pickup with the automatic is rated at 13,500 lb GCWR on a 3.73 and 15,000 lb on a 4.10. The V10 goes from 17,000 lb on a 3.73 to 20,000 lb on a 4.30. The 7.3L is rated 20,000 lb on either axle. The F-53 motorhome chassis pairs the 4R100 with the V10 at a 26,000 lb GCWR.

To estimate cruise RPM with the converter locked in 4th, use RPM = MPH x axle x 0.71 x 336 / tire diameter in inches. On a 31.6 inch tire at 65 mph, a 3.73 axle turns about 1,830 RPM and a 4.10 about 2,010 RPM. If you changed tire size, redo that math and recalibrate the speedometer, because the PCM schedules shifts off output speed.

Fluid type and capacity

Ford's 2003 F-250 through F-550 owner guide lists the 4R100 at 16.7 L (17.7 quarts) of Motorcraft MERCON ATF. Read the footnote: Ford calls that an approximate dry-fill capacity that varies with cooler size, and says the final level is set by the dipstick's normal operating range. A pan drop gives back only part of that because the converter and cooler stay full.

On fluid type, the original spec was MERCON (Motorcraft XT-2-QDX, per ATSG). Ford later issued TSB 06-14-4 making MERCON V the service fill for units that called for MERCON, which is what you buy today. Do not use MERCON SP; the same owner guide says MERCON, MERCON V and MERCON SP are not interchangeable, and SP was the TorqShift fluid.

Check level the way ATSG says: at normal operating temperature, 150 to 170 F, engine idling in Park, on the dipstick. A cold check reads low and people overfill.

Rebuild specs: clearances and hard parts

ATSG's clutch clearance specs for the packs you set with selective plates or snap rings:

Planetary carriers are model sensitive. ATSG notes both the forward and rear carriers came as 4-pinion or 6-pinion versions, and it recommends the 6-pinion carrier for its much higher torque capacity, especially in heavy-duty use. The 6-pinion rear carrier needs 3-tang thrust washers on both sides. If you are building a unit for a diesel or a heavy trailer and it came in with 4-pinion carriers, this is the cheapest strength upgrade in the box.

On the converter, Sonnax's identification guide says E4OD, 4R100 and 5R110W converters share the pilot diameter, flexplate bolt circle, overall height and 31 input splines, but the 4R100 turbine has a larger bore, 2.955 inch versus 2.765 inch on the E4OD. That bore is the quickest way to tell a 4R100 turbine on the bench.

Torque specs

From the ATSG torque chart:

Other specs worth knowing

• Shift quadrant: P, R, N, D, 2, 1, with an overdrive cancel button (TCS) on the shift lever and an "O/D OFF" lamp. Per ATSG, 2 gives a pull-in to 3rd, then holds 2nd after a downshift, and 1 pulls into 2nd then holds 1st.
• PTO: Some units are built for power take-off in every lever position. During PTO operation in OD, 4th gear is disabled (ATSG).
• Adaptive learning: Ford's owner guide says the 4R100 learns shift quality and must relearn after the battery is disconnected, taking a few hundred miles. A fresh rebuild or new battery will shift a little off until it does.

Need parts for this job?

Our 4R100 parts page has master rebuild kits, planetaries, sprags, drums, pumps, valve bodies and solenoid packs, with checkout on site. Confirm the model year, engine, 2WD or 4WD, and PTO or non-PTO before you order.

FAQ

What are the 4R100 gear ratios?

Per the ATSG 4R100 manual, 1st is 2.71:1, 2nd is 1.54:1, 3rd is 1.00:1, 4th (overdrive) is 0.71:1 and reverse is 2.18:1. The ratios are the same behind the 5.4L, 6.8L and 7.3L.

How much fluid does a 4R100 hold?

Ford's 2003 Super Duty owner guide lists 16.7 L (17.7 quarts). Ford calls that an approximate dry-fill figure that varies with cooler size, so set the final level on the dipstick at 150 to 170 F with the engine idling in Park. A pan drop only gives back part of it.

What fluid does a 4R100 take?

It was built for MERCON (Motorcraft XT-2-QDX). Ford TSB 06-14-4 replaced MERCON with MERCON V as the service fluid, so use MERCON V today. Do not use MERCON SP, which Ford says is not interchangeable.

Are 4R100 and E4OD gear ratios the same?

The 4R100 carries the same basic four-speed layout as the E4OD, and parts are close, but they are not all interchangeable. The converter turbine bore, for example, is 2.955 inch on the 4R100 versus 2.765 inch on the E4OD per Sonnax, so identify parts before you swap them.

What is the RPM at 65 mph with a 4R100?

With the converter locked in 4th (0.71), a 3.73 axle and a 31.6 inch tire turn about 1,830 RPM at 65 mph, and a 4.10 axle about 2,010 RPM. Use RPM = MPH x axle x 0.71 x 336 / tire diameter for your own setup.

Related guides

• 4R100 vs E4OD: Differences
• E4OD Gear Ratios and Specs
• 4L80E vs 4R100: Differences
• 4R100 Identification Guide
• 4R100 Towing Upgrades
• 4R100 Shift Solenoid Symptoms