NV4500 Hard Shifting Diagnosis and Repair

Hard shifting in manual transmissions can be caused by a number of issues from incorrect fluid/levels, temperature, to mechanical failures. When my 1999 Ram 3500 V10 suddenly became nearly impossible to shift coming home from work I began running through possible causes and checks to do once I got the truck home. At first the clutch was not fully disengaging and I assumed the master or slave cylinders failed. I headed to Rockauto.com to order a new hydraulic system for $70. A few days later when the parts showed up I swapped the hydraulic system out and went for a test drive. The clutch was still not fully disengaging but after few clutch pedal pushes a loud pop happened and the clutch would disengage completely. Thinking something must have not be seated fully, I embarked on a test drive. After just a few shifts I realized my problem was not resolved and my issue was deeper into the driveline. During the drive I was able to determine that the hard shifting was not gear specific and also intermittent. This told me that there was not an issue in the transmission or with the syncros. Now it was time to pull the transmission and inspect the clutch. My gut feel at this point was the pilot bearing had failed so the input shaft was not fully supported and causing hard shifts. The pilot bearing's job is to support the input shaft while allowing it to change speed during shifts. Since I was pulling the transmission it made sense to order a clutch. Its a big job and I don't want to have to do it again later just to potentially save a few bucks if the clutch looked good.


 

Unfortunately for the V10 Dodge's flywheels are discontinued and no aftermarket replacements are available. This means you have to hope your existing one is good enough to resurface or can get lucky and find a used one on eBay or in a junk yard. I am lucky to have a spare that came with an engine core I purchased a few years ago and had it resurfaced ahead of time at my local driveline shop. I was very happy with the job for the $50 it cost. The clutch I ordered was a standard replacement kit from LUK for $185. This included the friction disk, pressure plate, throw-out bearing, pilot bearing, and install tool.


 

Getting the NV4500 out of the truck was a bit of a chore but not overly difficult. The $130 Pittsburgh 450lb transmission jack from Harbor Freight worked well enough but was not ideal for this particular job. I was glad to have a 2wd truck as pulling a transfer case would have added to the difficulty.


 

Now that the transmission was out it was time to inspect the clutch. Upon removing the pressure plate and friction disk from the flywheel, I was greeted with chunks of metal falling to the floor. That's never a good sign. The flywheel side of the friction disk did not look too bad but the pressure plate side was a different story. As you can see below it was down to the rivets and full of debris. Additionally a few of the diaphragm spring retainers were broken and lodged in the coil springs. I suspect those breaking was the loud pop I heard earlier. I also found the remains of the roller from the pilot bearing throughout the clutch and on the floor. The pressure plate had signs of heat damage as well. It was evident this clutch lived a hard life and was completely used up. Glad I ordered a new one ahead of time.



 

Overall the flywheel looked to be in serviceable shape. A few hotspots and typical heat stress cracks on the surface. I will be able to have it resurfaced for a spare. The pilot bearing was toast and only a mangled shell remained. My guess is it failed long ago and the pieces from it eventually killed the clutch causing my hard shifting issues. I am excited to drive the truck with a fresh pilot bearing and expect the shifts to be buttery smooth. It was likely the pilot bearing was compromised the entire time I have owned the truck.


 

Installing the new clutch is no different than other vehicle so I wont detail that. I did included a few pictures along the way of installing the clutch.




 

After struggling to get the input shaft to engage, I did find that using some long bolts helped out lining everything up when mating the transmission to the bellhousing.


 

While the carnage I found in my truck may not be the cause of your shifting troubles, I hope it provides some insight on how to approach an issue. A fresh clutch and hydraulic system has my truck back on the road and shifting better than ever. The whole job cost me just under $500 including tools and a few evenings to complete.

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