Description
About This Transmission
The ZF5 is a German-built 5 speed manual transmission produced by ZF Friedrichshafen and used in Ford F-250 and F-350 heavy-duty trucks from 1987 through 1997. It replaced the BorgWarner T19 4-speed in Ford's diesel truck lineup, bringing with it a fifth overdrive gear, significantly higher torque capacity, and full synchronization on all gears including reverse- a major improvement over the T19's fully synchronized but lower-capacity design.
Two generations were produced. The S5-42 (1987 to 1994) was rated at 420 lb-ft of input torque and paired with the 6.9L IDI, 7.3L IDI, and early 7.3L Power Stroke diesel engines. The S5-47 (1995 to 1997) raised torque capacity to 470 lb-ft and was used with the 7.3L Power Stroke through 1997, when it was replaced by the ZF6 6-speed. The double-overdrive gearing- with both 4th gear (0.79:1) and 5th gear providing overdrive- made the ZF5 highly efficient for highway towing.
The ZF5 developed a reputation as one of the most durable manual transmissions ever fitted to an American light-duty truck. Cast iron case construction, robust synchronizers, and German engineering tolerances gave it exceptional longevity in demanding towing and commercial applications. Clean used ZF5 units are sought after not just for stock Ford replacements but also for custom diesel swap projects.
Signs You Need a Replacement Transmission
- Grinding or difficulty selecting reverse- reverse synchronizer wear, the most common ZF5 failure mode
- Difficulty engaging gears after the clutch pedal is depressed fully- hydraulic clutch system issue, not an internal transmission problem
- Gear popping out under load- worn detent springs or synchronizer rings on high-mileage units
- Leaking at the front or rear seal- input or output shaft seal wear on older units
- Whining or bearing noise at speed- input shaft bearing wear on high-mileage units
- Clutch not releasing fully- master or slave cylinder issue in the hydraulic clutch system
Known Problems With This Transmission
- Hydraulic clutch system- the most common ZF5 problem source: The ZF5 uses a hydraulic clutch system rather than a mechanical cable. The 1987 to 1991 trucks used an aluminum pedal bracket with small bushings that wear quickly, causing gear grinding and rough engagement. 1992-and-newer trucks used a steel pedal bracket with larger bushings- significantly more reliable. We note the year range of the unit and flag hydraulic system condition before shipping.
- Reverse synchronizer wear: Reverse is the most commonly worn gear on used ZF5 units. We test reverse engagement specifically and do not ship units with grinding reverse.
- Clutch slave cylinder travel: The ZF5 slave cylinder requires a minimum of 7/16 inch of travel for full clutch disengagement. Worn master cylinder or slave cylinder results in incomplete clutch release and difficult gear selection- frequently misdiagnosed as a transmission problem.
- Generation torque rating: The S5-42 is rated at 420 lb-ft. Heavily modified or high-output diesel builds can exceed this, particularly with chipped or tuned 7.3L IDI or Power Stroke engines. The S5-47 at 470 lb-ft handles moderately tuned applications better.
ZF5 Generations- Key Differences
Both generations share the same basic architecture but differ in torque capacity and some internal dimensions:
| Generation | Years | Torque Rating | Notes |
|---|---|---|---|
| S5-42 | 1987 to 1994 | 420 lb-ft | Paired with 6.9L IDI, 7.3L IDI, and early 7.3L Power Stroke. Aluminum pedal bracket (1987 to 1991) is the common clutch system failure point. |
| S5-47 | 1995 to 1997 | 470 lb-ft | Stronger internals. Paired with 7.3L Power Stroke exclusively. Steel pedal bracket era- more reliable hydraulic system. Replaced by ZF6 in 1998. |
What Is Included- What Is Not Included
| INCLUDED | Complete transmission assembly with all internal gears, synchronizers, shift forks, and rails. Dual PTO port covers. Output yoke where present. |
|---|---|
| NOT INCLUDED | Clutch disc, pressure plate, throwout bearing, flywheel, clutch master cylinder, clutch slave cylinder, transmission fluid. |
| Fluid Note | ZF5 transmissions use Dexron II or Mercon automatic transmission fluid- NOT gear oil. Do NOT fill with 75W-90 or similar gear oil. |
| Core Note | No core charge. You are not required to return your old transmission. |
Vehicle Compatibility- Direct Fit
The ZF5 was factory installed in the following Ford heavy-duty trucks:
| Ford F-250 and F-350 (1987 to 1994) | 6.9L IDI diesel, 7.3L IDI diesel, 7.3L Power Stroke- S5-42 |
|---|---|
| Ford F-250, F-350, and F-Super Duty (1995 to 1997) | 7.3L Power Stroke diesel- S5-47 |
| Some Gas Applications | 460 cubic inch V8 in F-250 and F-350- less common than diesel pairing |
| Custom Swap Applications | Popular behind Cummins 5.9L and other diesel swap projects using adapter kits |
The ZF5 is popular in custom diesel swap projects due to its high torque rating and durable cast iron case. Adapter kits exist to mate the ZF5 behind Cummins 5.9L and other non-Ford diesel engines. Call (240) 301-0095 with your specific swap requirements.
Transmission compatibility: ZF5 directly replaced the BorgWarner T19 4-speed in Ford applications. The ZF6 6-speed replaced the ZF5 in 1998.
Not sure if this fits? Call (240) 301-0095. We verify fitment before every order ships.
Common Names and Search Terms
| ZF5 | Most common buyer search |
|---|---|
| ZF 5-speed | Full name with speed designation |
| S5-42 | First generation designation |
| S5-47 | Second generation designation |
| Ford ZF5 | Brand-specific buyer |
| Ford diesel 5 speed | Application-specific search |
| 7.3 Power Stroke manual transmission | Engine-specific buyer |
| Ford F-250 5 speed | Truck model buyer |
| ZF5 for sale | Short purchase intent search |
| Ford heavy duty manual transmission | Heavy-duty application buyer |
Used OEM vs Rebuilt- Which Is Right for You?
Used OEM is the right choice for a straight F-250 or F-350 replacement where a gear-tested, generation-confirmed unit is needed. Our units are tested with generation and hydraulic clutch condition noted before shipping.
A rebuilt ZF5 from a Ford diesel specialist makes sense if you want fresh synchronizers and bearings throughout- particularly for high-output diesel builds that push torque levels above stock. Rebuilds typically run $1,500 to $3,000 or more. Call us to discuss options.
Condition and Inspection Process
- Gear engagement test through all 5 forward gears and reverse- reverse specifically tested and any grinding fails the unit
- Hydraulic clutch system components inspected- pedal bracket type and condition noted
- Input and output shaft inspection for end play, scoring, and bearing noise
- Case inspection for cracks and seal surface condition
- Fluid inspection for metal contamination
- Generation confirmed- S5-42 or S5-47 documented before shipping
Mileage varies by unit. Where available we provide it. Where it cannot be confirmed, we disclose this before your order is placed.
Buyer Tips- What to Know Before You Order
- Fluid type: The ZF5 uses Dexron II or Mercon ATF- not conventional gear oil. Many owners incorrectly fill with 75W-90 gear oil, which is too thick and damages synchronizers. Confirm fluid type at installation.
- Hydraulic clutch inspection: Before assuming the transmission has a problem, inspect the entire hydraulic clutch system. Worn master cylinder bushings, especially on 1987 to 1991 trucks, cause incomplete clutch release that mimics internal transmission failure. The Heim Joint Mod (eliminating the master cylinder pushrod eye bushing) is highly recommended for 1988 to 1997 trucks.
- Slave cylinder travel: The ZF5 requires a minimum 7/16 inch of slave cylinder travel for full clutch disengagement. Any less and gears will be difficult to engage and grind.
- S5-42 vs S5-47 for high-output builds: If running more than approximately 420 lb-ft from a chipped or tuned Power Stroke, the S5-47 is the preferred unit due to its higher torque rating.
- PTO ports: The ZF5 has dual PTO ports (driver and passenger side). These are often plugged from the factory. If you need PTO capability, confirm the ports are accessible on the unit you receive.
Why Buy From Vaz Auto Solutions
- Generation confirmed- S5-42 or S5-47 documented before you pay
- Gear tested through all 5 forward gears and reverse- reverse specifically validated
- Hydraulic clutch system components inspected and noted
- Fluid type disclosed- Dexron II/Mercon ATF requirement flagged on every order
- No core charge- keep your old transmission
- Free freight pallet delivery to all 50 states
- 15 day replacement warranty on internal transmission defects
- Call (240) 301-0095- speak with someone who understands ZF5 generations and Ford diesel truck applications
Mike Johnson (verified owner) –
Got the ZF5 for my ’94 Ford F-250. Solid purchase, shifts smooth, feels like new.
John Smith (verified owner) –
Ordered the ZF5 for my ’97 F-350. Arrived quickly, good condition, no complaints.
Dale R., Odessa TX –
Needed an S5-47 specifically for my Power Stroke. Vaz confirmed the generation before I paid and tested reverse — which is the first gear to go on a worn ZF5. Unit arrived clean. All gears shift smoothly including reverse. They also reminded me about Dexron ATF fluid which a lot of guys get wrong. Solid transaction.
Mark H., Amarillo TX –
Replaced the ZF5 in my IDI F-250. Vaz confirmed S5-42 and noted the hydraulic clutch system on the 1992 used the steel bracket which was good news. Transmission shifts great in all gears. One minor output seal seep — disclosed before shipping and fixed with a $12 seal at install. Would buy again.