When installing a new clutch...

[Loghead]

Do I have to put the NV4500 and bellhousing together before installing, or can I do the clutch, fork and bellhousing and then install the transmission - the way I've done clutches on every manual transmission before?

 

[BSeyler]

Do I have to put the NV4500 and bellhousing together before installing, or can I do the clutch, fork and bellhousing and then install the transmission - the way I've done clutches on every manual transmission before?

I've done it both ways. Just put one in mine a couple of months ago and put the bell housing on the transmission first. I liked the way it went together much better. When installing bell housing first and then transmission, I was afraid of the throwout bearing hanging up on the input shaft retainer and pulling the fork loose. The retainer on it isn't very strong. I do have a lift in my shop, so it was pretty easy to access the bolts at the top of the housing. I googled GCroyle's video and also have the FSM that I followed. I am very happy with the result.
https://www.youtube.com/watch?v=tS4H4oImDhE

 

[Loghead]

Thanks BSeyler,
I saw that video a bit earlier and noticed that indeed he installed the transmission with the bellhousing. I'm readying myself to swap out the automatic in the truck for the 4500.
I suppose that the lack of an inspection cover makes the possibility of knocking the fork out rather troubling.

Have you done all of the alignment checks covered in that video?

 

[BSeyler]

Yes, I did all of the alignment checks. Everything was within tolerance. The FSM helped with measurements. The video made it all make sense. When I last put a clutch in my pickup twelve years ago, I put the housing on first and then the transmission. Definitely liked putting the housing and transmission together as a unit better.

 

[GCroyle]

That truck with the separate bell housing allowed me to show stuff like runout insp that is a bit old school but pretty valid details. Now with NV5600 and G56 you can pretty much only check the dowel sleeves and matching hole conditions.

Gary

 

[The patriot]

Great video.
Thanks!

 

[BSeyler]

Gary,

When I replaced my clutch 12 year ago, I had the flywheel surfaced, which I now know was a mistake. The clutch would get grabby and I never did like it and was going to change it out when I got time, replacing all parts with new. With just over 100,000 miles, the pilot bearing failed. A couple of needles dropped out and bound up. When I pulled it apart, I found the two needles - they had carved a groove in the input shaft, but the rest of the pilot bearing didn't look bad, other than being dry. The flywheel showed the hot spots that had been there before. The pressure plate showed no discoloration and the disc showed little wear. I replaced the input shaft and all internals (including flywheel) when going back together and am happy with the end result. I was a little hesitant on the pilot bearing. I debating installing a brass bushing, but ended up with the needle bearing. Thoughts?

Thanks!
Bud

 

[GCroyle]

Bud,

Certainly a debated topic.

I've seen 5 scenarios.

No pilot. Common on front wheel drive and I installed a Tacoma V6 clutch that didn't use a pilot.
Bushing with a thin Teflon type coating. Japanese cars have used it.
Brass bronze bushing. Old school but still seen in lots of late model Nissans.
Needle bearing. Dodge, Ford, GM and Mazda have used it.
Ball bearing. Common on European and possibly some Asian.

Needles vs bushing.

Needles have higher load capacity size for size.
Needles can cause the failure you described.
Bushings just get larger and larger from wear and use.
Bushings frequently get greased by installer. WRONG LUBE! Use motor oil but they are oil impregnated. Grease makes em chirp. Ask me how I know that one, I did it on an old Ford F-100 I clutched in my driveway in earlier years.

I actually don't know which one outlasts the other.

Assuming a skilled install and not terrorizing the pilot at install and trans install, the biggest issue to me would be how you as the driver spend or conserve the pilots service life.

Biggest way to save pilot life, select N at stops whenever possible and take your foot off of the pedal.

Yes a needle when used up can damage an input shaft. I have quite a few old Ford input shafts that we've collected with damage and I attribute some of that to guys who brutally stab a trans destroying the needle at install.

Best advice I guess, attention to detail at install and conserve it by going to N as permitted.

Certainly debatable.

Gary

 

[BSeyler]

Gary,

Thanks for the reply. Maybe I damaged the bearing when I put it together the last time - hard to remember that far back and how hard it was to get it together. I did that one laying on the ground. This time, I made sure that it was sliding together easily before I installed any bolts in the housing, and only took them up by hand as I slid it together. Having a shop with a lift is great and I just wish I could have done it earlier in life! I learned many years ago to keep my foot off of the pedal unless needed when learning to drive. My dad drove for a living for many years and was adamant about how clutches were used. I passed that on to my kids. Maybe it was luck of the draw on the old bearing. Your video made me think about getting it right on this install and I appreciate the help you give us!

Bud

 

[GCroyle]

Thanks Bud. I enjoy the driving link between engine, trans, vehicle and what needs to be done that a clutch provides.

Gary

 

[Tuesdak]

Gary,

When I replaced my clutch 12 year ago, I had the flywheel surfaced, which I now know was a mistake. The clutch would get grabby and I never did like it and was going to change it out when I got time, replacing all parts with new. ... The flywheel showed the hot spots that had been there before. The pressure plate showed no discoloration and the disc showed little wear. I was a little hesitant on the pilot bearing. I debating installing a brass bushing, but ended up with the needle bearing. Thoughts?

Thanks!
Bud

Flywheels and brake rotors are wear items. It's debatable if they are throw away items or can be surfaced. One of the pass/fail tests that IMO most overlook is the "hot-spots" that are visible before trash rotors/flywheels are machined. Sometimes you can even feel it with a fingernail. The hot spots are from the temperature getting over 1200-1300 degrees F and the cast iron turning into cementite, iron carbide. The cementite can expand leaving you a fingernail hanger on the surface. The same material carbide cutting tool isn't going to knock this layer off and it can go deep. The cutting tool bounces off the stuff.

On brakes cementite trashed rotors usually come back in 3000 miles for pedal pulse while stopping. Two reasons really: The cementite causing a problem and the CAFE undersized brakes that caused the problem in the first place. In order to prevent undersized CAFE brakes from overheating you have to 'roll' on the brakes after a hard stop: Don't keep the red hot pads over a red hot rotor while the rest of the rotor cools down. Roll it a bit to cool the entire rotor so you don't have a hot spot turning to cementite under the hot pads. Shift to reverse and back it up a few feet if you have too after a panic stop! Regardless this is why you see some people drift forward and stop again a few times at a stop light. This same process can ruin a flywheel with a slipping clutch. Just get the surface hot enough.

After some trial and error the aftermarket clutch industry has made ball bearing pilot bearings available to us. Ball Bearings are found on imports. You know imports: Q: "Why do you roll the threads like (Champion Spark Plug) does?" A: "It's the only thing we couldn't improve on."

 

[GCroyle]

JD,

Interesting and I'm not challenging your description, but I'll add what we learned years ago about those hot spots.

We're part of Marmon and had a visit from their Sr casting engineer guru who spent his career in mostly big brake drums and we posed same hot spot questions. He took a look at the subject flywheel and pronounced it Martensite and educated us on its negative nasty habits. Biggest bad habit I learned about was its ability to grow back and create high spots & chatter.

Martensite or Cementite I can't determine but its bad stuff and I can frequently introduce it to someone by looking for shadows in a resurfaced FW from the hot spots.

Good info.

Gary

 

[petersonj]

Assuming a skilled install and not terrorizing the pilot at install and trans install, the biggest issue to me would be how you as the driver spend or conserve the pilots service life.

Biggest way to save pilot life, select N at stops whenever possible and take your foot off of the pedal.

You make a very good point here and I agree. Another hardly ever mentioned scenario for early pilot bearing failure is poor gear shifting habits – specifically , not matching road speed to engine speed during a downshift. A good example is as follows:

Driver is at highway speed in high gear and is approaching an intersection with the intention of turning left. As the driver appoaches intersection with no oncoming traffic, he figures that 3rd gear will be appropriate for the turn. The driver slows, presses the clutch pedal (engine drops to idle) and then driver starts pushing the gearshifter into 3rd gear. The road speed forces the synchronizer to bring third gear up to speed which brings the transmission input shaft up to speed as well. Since the clutch pedal is still depressed the input shaft speed will be considerable greater than the idling engine speed – result, more wear on the pilot bearing (and the 3rd gear synchronizer as well).

So, even the best quality clutch install with the best quality parts can be negated signififcantly by poor driver habits.

Experienced over-the-road truck drivers use the throttle to unload the drive train at the beginning of a downshift to pull the transmission out of gear. Then (still using throttle control while the transmission is out of gear) bring engine speed up to match road speed for the lower gear being selected. The gear is selected still using throttle control to engage the drive train in an unloaded manner. This operation is very smooth and done without the clutch pedal ever being depressed. During the shift there is no wear on the pilot bearing because the clutch is always engaged and spinning the transmission input shaft, and there no wear on the clutch because the transmission is being shfted in and out of gear when there is no load on the drive train.

The transmissions in our trucks are not designed to be shifted without using the clutch, but if one fully understands what is going on during a shift, one can use the throttle to match engine speed to road speed during a shift (clutch must be engaged – foot off pedal – while passing through neutral).

- John