Hoss 350
My GSP, Dutch
Changing your clutch for the DIY’er and the clinically insane, by Hoss 350.
The ZF 6-speed transmission in the Superduty pickups is IMHO one of the best manual transmissions driving down the road today for light medium duty applications. It is built stout and is mostly bulletproof. However, any machine is only as strong as its weakest link, and Ford managed, quite efficiently, to build an extremely weak link into this transmission. The “release arm”, A.K.A “clutch fork” on these machines is a pathetically weak pot-metal POS, which has a very finite number of clutch operation cycles before it breaks in half, leaving you effectively stranded wherever you are. I had this happen to me, and I would like to share my experiences in changing this part with you, the reader, in an effort to help you make the process of repairing this little nightmare as easily as possible.
Now, you may be one of the lucky ones, who is changing the clutch because it wore out, not because the release arm broke. If so, congratulations! If you are one of the unlucky many who’s release arm did fail, I feel your pain. However, I want to make one thing clear, and THIS IS IMPORTANT, SO PLEASE READ!!!!
NO MATTER WHAT YOUR MODE OF FAILURE, WHETHER IT WAS WEAR OR A BROKEN RELEASE ARM OR BAD THROW-OUT BEARING OR WHATEVER, THE COST TO FIX THE PROBLEM IS EXACTLY THE SAME!!! This is because while you have the transmission out, you are going to replace everything, anyway! It would be a crying shame for those of you that replace the clutch for wear issues to fix it, and then have your release arm break two weeks later, causing you to have to pull the trans again. The same goes for the broken release arm guys. While harder to justify the extra cost of a clutch, it is worth it to replace it now instead of having to do the job again sooner rather than later.
The parts you will need include the following:
1.) New clutch disc & pressure plate;
2.) New flywheel (depending on application). The LUK and Southbend options generally incorporate a larger flywheel in the kit. However, clutches are available that use the factory flywheel. You decide which is best for your application. However, if you do decide to use the factory flywheel, you must have it resurfaced by a machine shop, which can take a couple days, lengthening your project duration;
3.) New bolts for the flywheel and pressure plate, usually included in the kit you buy;
4.) Upgraded, stronger release arm (about $30), with fulcrum block (or pivot block);
5.) New throwout bearing, typically included in the clutch kit;
6.) New, upgraded Kevlar pilot bearing. The factory roller-style pilot bearings have led to transmission failures due to premature wear-out. The Kevlar bushing fixes this problem;
All of this will cost $500-$1,100 depending on the quality and rating of the clutch kit.
Now, roll up your sleeves, because here we go. Time to drop the transmission.
First, we start by dropping the drivelines. The bolts on the front of the rear and the rear of the front drivelines are 12-point ½” heads. Get your ½” socket out and take the front of the rear driveline off. MAKE SURE TO MARK 2-PIECE DRIVELINES FOR ALIGNMENT, or you will have to re-balance the driveline if you don’t get it back together properly. The rear driveline will flop out of the way without taking it off the rear, so save your time and just drop the front. The front driveline should come off all the way. It gets in the way if you don’t pull it off.
Second, we decide whether to drop the T-case on 4x4 models. I highly recommend splitting the T-case off the trans for this job. It is only 6 bolts, and it makes the tranny alignment phase SOOO much easier. Do what you want, but you were warned. You have to disconnect the t-case linkage, which just prys off, and there are two electrical connections, one on the T-case, on the trans, which also need removed. The T-case linkage also has a big 15/16 bolts holding it on to the trans which will need to be taken off.
Third, pull the starter off. Before you start this job, be smart and disconnect the negatives on both batteries. The feed for the started is a very high amp line. It will spark a lot if you arc it over, which is not good. Three bolts hold the starter to the trans bellhousing. It is heavy, get someone to hold it while you take the bolts out, otherwise it will fall on your head. I cannot remember what size the bolts were, either 9/16 or ½ if memory serves. Take the two electrical lines off the back, and put your starter in a safe, dry place.
The shifter comes off by removing the four Phillips-head screws in the shifter boot hold down, then removing the 6 6mm allen head bolts holding the shifter on. It pops right off after you have pulled these out. Additionally, it is IMPERATIVE that you put the tranny into gear before you take the shifter off. This will allow you to spin the tail shaft, to in turn spin the input shaft, as you are trying to align the shaft to the clutch hub during reinstallation.
Take off the cooler lines.
Now is the time to talk about jacks. Get a tranny jack. Period. This transmission is very heavy, and if it rolls off your floor jack that you are trying to use as a tranny jack, it will probably kill you. Not only that, but the alignment features on the tranny jack will come in handy later.
Support the tranny, and pull the crossmember off. The nuts are ¾ inch. The bolts have keepers on them that prevent them from spinning, so you don’t have to double-wrench the procedure. It helps a lot.
Now, the bellhousing bolts. They are also ¾”, IIRC, and there are six of them, three on each side. The drivers side bolts are easy as pie to get to. Two of them are on the “side” of the bellhousing, one goes way up on top. All three can be gotten to with a ratchet with about 4-5” of extension on it. You don’t need wobble-joints for this job. However, the passenger side, with the starter housing and downpipe, SUCKS. The two on the side can be gotten to with a ratchet and about 6” of extension. The one on top requires about 8” of extension, a u-joint, about 6” more extension, another u-joint, and then about a 3” extension with the socket on it. You will see what I mean when you get there. Once you get it out, though, the tranny will come right out. Drop it to the floor and get it out of your way.
Take a second to have a beer, and reflect. You are half-way there… Well, almost….
Start with the transmission side of the effort. Look closely at how everything is installed in the bellhousing, because that is how you will have to reinstall it later. The release arm, throw-out bearing, and pivot block all just pull off the input shaft, with a little effort to pull the pivot block out of its hole (it just snaps in). Reinstall everything the same as you took it out. This part takes 5 minutes of you stop for beer a lot.
Now, go to the flywheel side of things. 8 bolts hold the pressure plate on. They are ½ IIRC. Take them off, and the heavy pressure plate will fall on you, unless you have a friend hold the pressure plate for you while you pull the bolts out. The clutch disc will come out with the pressure plate. Pay attention to how it is oriented, as the new one will have to be reinstalled the same, and they are directional.
10 bolts hold the flywheel in place. They are 18MM, IIRC. The flywheel is also heavy. Have someone hold it for you while you pull the bolts.
Reinstall your new flywheel with NEW BOLTS. Torque to 100 ft lbs, or as according to the flywheel manufacturer.
Reinstall the pressure plate and disc. There are a couple things to keep in mind here. Use your alignment tool, as supplied with your clutch kit, BUT DO NOT RELY ON IT!!!! I mean it. It WILL NOT ALIGN THE CLUTCH DISC PROPERLY ON ITS OWN!!! YOU HAVE TO GET UP THERE ARE EYEBALL IT!!! Tighten the pressure plate down enough so that the disc is held in place, but you can still move it. Align it by sight, then tighten the pressure plate back down, sequentially, in a star pattern, a little at a time, so you do not bend or warp stuff. Torque to 20 ft lbs, or as specified by manufacturer.
I relied on my alignment tool and had a 4 ½ hour nightmare trying to get the tranny on, until I pulled everything back apart and re-aligned the disc. It slipped right back on after that.
When putting the tranny back in place, do not allow it to rest on the disc, as it will bend it. Turn the rear tail shaft to align the splines. Do not pull the jack off the tranny until all six bellhousing bolts and the crossmember have been put back and tightened into place. This will mess up your clutch disc. Use the flywheel as a way to tell if you are at the right angle of entry, or are not high enough or are too high for alignment.
Put everything back on opposite of how you took it off. Reconnect batteries. Drive normal for about 200 miles before towing or hauling anything really big.
See that wasn’t so bad! Think of all the money you saved doing it yourself. Now you can afford that tuner or chip you’ve always wanted, or that lift kit, or the water injection or the……..
I have to stop myself. Good luck, and keep your cool. It can get frustrating at times, but things work out if you stay cool.
The ZF 6-speed transmission in the Superduty pickups is IMHO one of the best manual transmissions driving down the road today for light medium duty applications. It is built stout and is mostly bulletproof. However, any machine is only as strong as its weakest link, and Ford managed, quite efficiently, to build an extremely weak link into this transmission. The “release arm”, A.K.A “clutch fork” on these machines is a pathetically weak pot-metal POS, which has a very finite number of clutch operation cycles before it breaks in half, leaving you effectively stranded wherever you are. I had this happen to me, and I would like to share my experiences in changing this part with you, the reader, in an effort to help you make the process of repairing this little nightmare as easily as possible.
Now, you may be one of the lucky ones, who is changing the clutch because it wore out, not because the release arm broke. If so, congratulations! If you are one of the unlucky many who’s release arm did fail, I feel your pain. However, I want to make one thing clear, and THIS IS IMPORTANT, SO PLEASE READ!!!!
NO MATTER WHAT YOUR MODE OF FAILURE, WHETHER IT WAS WEAR OR A BROKEN RELEASE ARM OR BAD THROW-OUT BEARING OR WHATEVER, THE COST TO FIX THE PROBLEM IS EXACTLY THE SAME!!! This is because while you have the transmission out, you are going to replace everything, anyway! It would be a crying shame for those of you that replace the clutch for wear issues to fix it, and then have your release arm break two weeks later, causing you to have to pull the trans again. The same goes for the broken release arm guys. While harder to justify the extra cost of a clutch, it is worth it to replace it now instead of having to do the job again sooner rather than later.
The parts you will need include the following:
1.) New clutch disc & pressure plate;
2.) New flywheel (depending on application). The LUK and Southbend options generally incorporate a larger flywheel in the kit. However, clutches are available that use the factory flywheel. You decide which is best for your application. However, if you do decide to use the factory flywheel, you must have it resurfaced by a machine shop, which can take a couple days, lengthening your project duration;
3.) New bolts for the flywheel and pressure plate, usually included in the kit you buy;
4.) Upgraded, stronger release arm (about $30), with fulcrum block (or pivot block);
5.) New throwout bearing, typically included in the clutch kit;
6.) New, upgraded Kevlar pilot bearing. The factory roller-style pilot bearings have led to transmission failures due to premature wear-out. The Kevlar bushing fixes this problem;
All of this will cost $500-$1,100 depending on the quality and rating of the clutch kit.
Now, roll up your sleeves, because here we go. Time to drop the transmission.
First, we start by dropping the drivelines. The bolts on the front of the rear and the rear of the front drivelines are 12-point ½” heads. Get your ½” socket out and take the front of the rear driveline off. MAKE SURE TO MARK 2-PIECE DRIVELINES FOR ALIGNMENT, or you will have to re-balance the driveline if you don’t get it back together properly. The rear driveline will flop out of the way without taking it off the rear, so save your time and just drop the front. The front driveline should come off all the way. It gets in the way if you don’t pull it off.
Second, we decide whether to drop the T-case on 4x4 models. I highly recommend splitting the T-case off the trans for this job. It is only 6 bolts, and it makes the tranny alignment phase SOOO much easier. Do what you want, but you were warned. You have to disconnect the t-case linkage, which just prys off, and there are two electrical connections, one on the T-case, on the trans, which also need removed. The T-case linkage also has a big 15/16 bolts holding it on to the trans which will need to be taken off.
Third, pull the starter off. Before you start this job, be smart and disconnect the negatives on both batteries. The feed for the started is a very high amp line. It will spark a lot if you arc it over, which is not good. Three bolts hold the starter to the trans bellhousing. It is heavy, get someone to hold it while you take the bolts out, otherwise it will fall on your head. I cannot remember what size the bolts were, either 9/16 or ½ if memory serves. Take the two electrical lines off the back, and put your starter in a safe, dry place.
The shifter comes off by removing the four Phillips-head screws in the shifter boot hold down, then removing the 6 6mm allen head bolts holding the shifter on. It pops right off after you have pulled these out. Additionally, it is IMPERATIVE that you put the tranny into gear before you take the shifter off. This will allow you to spin the tail shaft, to in turn spin the input shaft, as you are trying to align the shaft to the clutch hub during reinstallation.
Take off the cooler lines.
Now is the time to talk about jacks. Get a tranny jack. Period. This transmission is very heavy, and if it rolls off your floor jack that you are trying to use as a tranny jack, it will probably kill you. Not only that, but the alignment features on the tranny jack will come in handy later.
Support the tranny, and pull the crossmember off. The nuts are ¾ inch. The bolts have keepers on them that prevent them from spinning, so you don’t have to double-wrench the procedure. It helps a lot.
Now, the bellhousing bolts. They are also ¾”, IIRC, and there are six of them, three on each side. The drivers side bolts are easy as pie to get to. Two of them are on the “side” of the bellhousing, one goes way up on top. All three can be gotten to with a ratchet with about 4-5” of extension on it. You don’t need wobble-joints for this job. However, the passenger side, with the starter housing and downpipe, SUCKS. The two on the side can be gotten to with a ratchet and about 6” of extension. The one on top requires about 8” of extension, a u-joint, about 6” more extension, another u-joint, and then about a 3” extension with the socket on it. You will see what I mean when you get there. Once you get it out, though, the tranny will come right out. Drop it to the floor and get it out of your way.
Take a second to have a beer, and reflect. You are half-way there… Well, almost….
Start with the transmission side of the effort. Look closely at how everything is installed in the bellhousing, because that is how you will have to reinstall it later. The release arm, throw-out bearing, and pivot block all just pull off the input shaft, with a little effort to pull the pivot block out of its hole (it just snaps in). Reinstall everything the same as you took it out. This part takes 5 minutes of you stop for beer a lot.
Now, go to the flywheel side of things. 8 bolts hold the pressure plate on. They are ½ IIRC. Take them off, and the heavy pressure plate will fall on you, unless you have a friend hold the pressure plate for you while you pull the bolts out. The clutch disc will come out with the pressure plate. Pay attention to how it is oriented, as the new one will have to be reinstalled the same, and they are directional.
10 bolts hold the flywheel in place. They are 18MM, IIRC. The flywheel is also heavy. Have someone hold it for you while you pull the bolts.
Reinstall your new flywheel with NEW BOLTS. Torque to 100 ft lbs, or as according to the flywheel manufacturer.
Reinstall the pressure plate and disc. There are a couple things to keep in mind here. Use your alignment tool, as supplied with your clutch kit, BUT DO NOT RELY ON IT!!!! I mean it. It WILL NOT ALIGN THE CLUTCH DISC PROPERLY ON ITS OWN!!! YOU HAVE TO GET UP THERE ARE EYEBALL IT!!! Tighten the pressure plate down enough so that the disc is held in place, but you can still move it. Align it by sight, then tighten the pressure plate back down, sequentially, in a star pattern, a little at a time, so you do not bend or warp stuff. Torque to 20 ft lbs, or as specified by manufacturer.
I relied on my alignment tool and had a 4 ½ hour nightmare trying to get the tranny on, until I pulled everything back apart and re-aligned the disc. It slipped right back on after that.
When putting the tranny back in place, do not allow it to rest on the disc, as it will bend it. Turn the rear tail shaft to align the splines. Do not pull the jack off the tranny until all six bellhousing bolts and the crossmember have been put back and tightened into place. This will mess up your clutch disc. Use the flywheel as a way to tell if you are at the right angle of entry, or are not high enough or are too high for alignment.
Put everything back on opposite of how you took it off. Reconnect batteries. Drive normal for about 200 miles before towing or hauling anything really big.
See that wasn’t so bad! Think of all the money you saved doing it yourself. Now you can afford that tuner or chip you’ve always wanted, or that lift kit, or the water injection or the……..
I have to stop myself. Good luck, and keep your cool. It can get frustrating at times, but things work out if you stay cool.
