Hi all. I’m at the point where I’m about to unbolt the motor mounts and take out the 4.3 to swap in a 5.3. My question is how to release the clutch fork. I’m going to keep the tranny mounted and plan on removing the engine only. The starter is pulled and all the bell housing bolts are removed. Driveshaft and tranny mount are still attached as well. Is the clutch fork visible and able to be released from the starter area? Any help us much appreciated!

 

The clutch fork pivots on a ball inside the bellhousing. It clips to the throwout bearing. When you move the fork, it pushes the throwout bearing into contact with the pressure plate fingers, and disengages the clutch. When you're not pressing on the clutch pedal, the throwout bearing is not in contact with the pressure plate at all. In the relaxed state, there is no physical connection between the rotating and non-rotating members.

When pulling the engine, the flywheel, clutch disk, and pressure plate come out with the engine. The fork and throwout bearing stay behind. So in simple answer to your question, you don't have to do anything to the clutch fork or throwout bearing when pulling the engine. If you have the bellhousing bolts out, it's ready to come apart. You'll understand the clutch linkage better once you've gotten the engine out and can examine things.

There are two dowel pins in the engine block(at 9 o'clock and 3 o'clock) that align the bellhousing during assembly. These can be a bit sticky, so you might need to pry a bit to get the bellhousing loose from the block. The dowel pins should be visible through the backside of the bellhousing. They look like tapered bolts without heads. Spray some penetrating lube on those if they're holding you up.

 

Thanks for the response Kipps! For this build I’m looking to pull the engine only and leaving the trans in as well as the driveshaft connected. Is it possible to release the clutch fork by hand just to make sure it doesn’t get hung up while I pull the motor from the trans? Do you know of anyone who left the trans in and what they said about attaching the motor back to the trans when reinstalling? I appreciate your feedback!

 

There's nothing to be released on the clutch fork. The clutch fork clips into the throwout bearing, and the throwout bearing slides on the input shaft retainer. Neither one can possibly cause you any problem in pulling the engine. Once you get the engine out, you'll see what I mean.

Hang the engine from a hoist, remove the engine mounts, support the transmission, "unstick" the bellhousing from the block, swing the engine forward about 6 inches, and lift it out. Don't worry about the clutch fork. It doesn't even factor in here.

I googled pics of a nv3500 bellhousing. I came up with this thread. This transmission appears nearly typical, except for two areas. #1, the bellhousing is integral with the tranny. This doesn't affect the job you're attempting. #2, the clutch fork doesn't come all the way out of the bellhousing. It appears that the slave cylinder engages with the fork inside the bellhousing casting. This means that you literally cannot pull the fork out of the housing until you split off the engine.

Note the second pic. It shows a rusty looking object in the center of the bellhousing. This is the input shaft retainer. It holds the bearing and seal for the input shaft. It also provides a smooth surface for the throwout bearing to slide on. The throwout bearing is the shiny round donut in the center. This is pushed forward by the fork, until it's bearing surface meets the fingers on the pressure plate.

Note the fourth pic. This shows the complete flywheel/clutch/pressure-plate assembly mounted to the engine. Your engine will look like this when you pull it. When your foot is off the clutch pedal, the throwout bearing that I mentioned earlier is hovering a fraction of an inch away from those fingers in the middle of the pressure plate. When you depress the clutch pedal, the throwout bearing is pushed into those fingers, which in turn pivot, and lift the pressure plate off the clutch disk.

 

Great response Kipps! After reading so many articles on here about the issue it sounds like the articles I read were for different transmissions. I really appreciate your write up and now I’m confident I will not have a clutch fork issue when pulling the motor from tranny. Fingers crossed everything goes as planned!

 

Did you ever finish? I am in the midst of dropping an NV3500, out of an 02 Silverado 4.3L, behind a 5.3L. I need to buy the clutch, but am curious if you had to do anything special since the 4.3 and 5.3 are different families.

Thanks!