Replacing a clutch on your manual transmission
Replacing a manual transmission’s clutch is not for the faint of heart. Yet for experienced mechanics, professionals or seasoned shade tree types, DIY clutch replacement is a good way to save money as long as you're up to the challenge of the variables your vehicle can throw at you. The following should give you a good idea of the difficulties and obstacles involved.
Considering DIY clutch replacement
For the average auto owner, farming out major repairs is usually wise. Sure, saving on labor charges can be enticing, but hidden costs often undermine good intentions. (As a worst-case scenario, one emergency room trip can make any at-home auto repair extremely non-worthwhile.) Besides, most shops offer some kind of warranty on their work, so the car owner has some recourse should the repair fail within a specified length of time. (Parts warranties can be denied if the manufacturer deems that they were improperly installed by a do-it-yourselfer.)
Circumstances sometimes prompt the hardcore do-it-yourselfer to rise to the challenge of a major car repair. The intent here is to provide an overview of the tools and tricks necessary to replace a clutch in your garage or driveway. Armed with this insight, you can decide whether or not biting off this job will be more than you can chew.
Clutch case history
The demonstration vehicle is a 4WD Isuzu Trooper. It offers a variety of variables not found on all vehicles: two shift levers, the added weight and bulk of a transfer case, a front driveshaft, an exhaust crossover pipe, hydraulic clutch linkage system, undercarriage skid plates, higher-than-average-cost replacement parts and tight access to many bolts (on account of the aforementioned components). The labor quote on a vehicle of this stature can be as much as twice the cost of the parts (which themselves are surprisingly higher than the typical million-selling car). On the plus side, this body-lifted Trooper has oversized tires that create enough clearance under the vehicle to access the necessary parts without having to raise the truck and put it on jack stands. So we simply blocked the tires.
To reiterate, this isn't necessarily a step-by-step how-to on clutch replacement. Instead, it's an overview of some of the challenges to expect if you're considering doing this at home. The clutch job shown here took two weekend mechanics armed with air tools working from 9 a.m.-6 p.m. (including a lunch break) to get the flywheel resurfaced. The bottom line: What's your time worth and are you willing to redo/troubleshoot your work should something not function afterward?
Clutch installation tips
If this primer on clutch replacement hasn't overwhelmed you, and you've got the time and the tools, then it’s time to get started. Tackling a clutch job doesn't have to be all hard work.
- Park the vehicle on a level surface.
- Disconnect the negative battery cable.
- If necessary, raise the vehicle and secure it on jack stands to allow enough room to work. Using two floor jacks provides an extra margin of safety.
- Read the clutch kit's instructions and refer to a service manual before beginning.
- A come-along or hand winch can be helpful when rolling the transmission/crossmember away from the engine on a floor jack.
- Accumulate socket extensions of varying lengths as well as socket "wobble" joints.
- Just as brake rotors and drums should be "turned" when replacing pads and shoes, always resurface the flywheel as part of a clutch job. Replace a too-worn flywheel if necessary. Clean any grease off the flywheel before installing the new clutch.
- Once it's removed, inspect the old clutch for signs of other problems. (Oil on the clutch indicates a seal problem on the engine and/or transmission.)
- Indicators of engine/transmission misalignment: uneven wear on the pilot bushing/throwout bearing, clutch surface itself or clutch disc splines, broken clutch retainer plate or springs and uneven wear on a transmission input shaft bearing.
- Common causes of engine/transmission misalignment: broken engine or transmission mounts, warped bellhousing, loose flywheel and damaged bellhousing dowel pins.