PSA: National throw out bearing failed after seven months of use

[MikekiM]

The all metal National Throwout bearing has been recommended here a few times so when I replaced the NV3550 transmission with a NIB Novak AX15 in Q4-2024, I did the National instead of the plastic piece included in the LUK clutch kit.

Started to hear some clicking when the clutch was pressed and released. Thought it was the clutch MC & slave so ordered a new one of those direct from Mopar and while I waited for it to come in, the TO bear failed and took the (possible good) clutch slave with it.

Replacing the National TO bearing with a Mopar unit.

FWIW, this was the third or fourth clutch MC+Slave I installed in the past 12 months. First two were Duralast from the local auto parts store. The next was a LUK kit.

Can't say whether there is issue with the National TO bearings, but I won't be using one again.

 

[jeepguy03]

About how many miles on it?

 

[MBDIAGMAN]

I doubt that the brand of the bearing had any effect in the matter. Either hydraulic system has something causing it to slightly touch the bearing, keeping it rotating all the time or someone is subconsciously riding the clutch(not likely.)

Clutch life varies WILDLY from one driver to another. For those who have mastered the art of getting it rolling only using the clutch without touching the gas,THEN accelerating through the gears plus driving mostly highway miles, a clutch can last virtually forever. On the other end of that is the person who slips it too much under heavy power to start creating lots of heat in the friction area. There is everything in between.

My Dad taught me to get rolling without touching the gas and he didn’t consider me competent until I could do so every time. He also wouldn’t tolerate my foot on the clutch pedal unless I was getting rolling or shifting gears.

I’m not saying the OP has any of these bad habits, but if so, develop new habits and make sure the TO bearing is not spinning with pedal released.

Hope this helps

 

[machoheadgames]

I doubt that the brand of the bearing had any effect in the matter. Either hydraulic system has something causing it to slightly touch the bearing, keeping it rotating all the time or someone is subconsciously riding the clutch(not likely.)

Clutch life varies WILDLY from one driver to another. For those who have mastered the art of getting it rolling only using the clutch without touching the gas,THEN accelerating through the gears plus driving mostly highway miles, a clutch can last virtually forever. On the other end of that is the person who slips it too much under heavy power to start creating lots of heat in the friction area. There is everything in between.

My Dad taught me to get rolling without touching the gas and he didn’t consider me competent until I could do so every time. He also wouldn’t tolerate my foot on the clutch pedal unless I was getting rolling or shifting gears.

I’m not saying the OP has any of these bad habits, but if so, develop new habits and make sure the TO bearing is not spinning with pedal released.

Hope this helps

You can’t do anything as a driver to affect the throw out bearing. In stock form, it already IS spinning full time due to the spring in the slave cylinder constantly pushing on the release fork at all times. Whether you hit the clutch or not doesn’t do anything to the bearing besides preload it a bit more, but it is already spinning regardless. All modern clutches work that way.

National TOBs are well known for being junk. Mopar should be a better choice.

 

[MBDIAGMAN]

The hydraulic clutches I have experience with are Mercedes of the seventies through the nineties had an eccentric on the linkage to adjust to prevent constant contact. I’m amazed that anyone would design for constant rotation of the bearing. Sounds like poor engineering.

Thanks for the correction about the design and the tip on the poor parts.

 

[MikekiM]

About how many miles on it?

About 9k

I doubt that the brand of the bearing had any effect in the matter. Either hydraulic system has something causing it to slightly touch the bearing, keeping it rotating all the time or someone is subconsciously riding the clutch(not likely.)

Clutch life varies WILDLY from one driver to another. For those who have mastered the art of getting it rolling only using the clutch without touching the gas,THEN accelerating through the gears plus driving mostly highway miles, a clutch can last virtually forever. On the other end of that is the person who slips it too much under heavy power to start creating lots of heat in the friction area. There is everything in between.

My Dad taught me to get rolling without touching the gas and he didn’t consider me competent until I could do so every time. He also wouldn’t tolerate my foot on the clutch pedal unless I was getting rolling or shifting gears.

I’m not saying the OP has any of these bad habits, but if so, develop new habits and make sure the TO bearing is not spinning with pedal released.

Hope this helps

I have none of the habits you describe. Been driving a manual for nearly five decades.
Take from the post what you will.

National TOBs are well known for being junk. Mopar should be a better choice.

I recall a few folks here suggesting as a good alternative give the TOB that comes with the LUK clutch kit is plastic. My bad on this one.
Costly mistake on my part.

 

[machoheadgames]

The hydraulic clutches I have experience with are Mercedes of the seventies through the nineties had an eccentric on the linkage to adjust to prevent constant contact. I’m amazed that anyone would design for constant rotation of the bearing. Sounds like poor engineering.

Thanks for the correction about the design and the tip on the poor parts.

It’s not really a bad design. It keeps from ever having to adjust clearance. On a design where the bearing doesn’t touch the pressure plate, you have to make adjustments every once in a while to keep the bearing off the plate as the clutch wears.

 

[machoheadgames]

About 9k


I have none of the habits you describe. Been driving a manual for nearly five decades.
Take from the post what you will.


I recall a few folks here suggesting as a good alternative give the TOB that comes with the LUK clutch kit is plastic. My bad on this one.
Costly mistake on my part.

It has been recommended by many in the “plastic = bad” camp. It isn’t a great alternative though. I didn’t have trouble with the one National I installed but it was only in there for 10k or so and it didn’t give me the warm fuzzies when I installed it.

 

[jeepguy03]

National TOBs are well known for being junk. Mopar should be a better choice.

Who makes the Mopar one? It might be Luk. I don't know if it is any one brand being junk, but more like poor quality control across the board. My last Mopar water pump lasted about 3 days, but the $40 AC Delco one I threw in quick to "get by" has been fine for a year now. It's really a toss up with parts these days unfortunately.

 

[machoheadgames]

Who makes the Mopar one? It might be Luk. I don't know if it is any one brand being junk, but more like poor quality control across the board. My last Mopar water pump lasted about 3 days, but the $40 AC Delco one I threw in quick to "get by" has been fine for a year now. It's really a toss up with parts these days unfortunately.

No idea who makes it, but it's been the same part number for 30 years. I have witnessed Luk metal, Luk plastic, National, Mopar, and SKF in person. Luk metal was similar to the Mopar but they did have a few small differences. SKF looked very different from the rest, hard to explain but the pics online can show it. National looked similar to Luk metal and Mopar, but it didn't feel as good in rotations and the pressure plate finger surface could move around a bit more.

Since the original part number remains unchanged and available for purchase, I think Mopar is the best bet.

Water pumps are different because they have had a number of part numbers for those over the years and aside from the actual originals, have had very sketchy track records.

 

[MikekiM]

I don't know if it's better or not, or if I have a bigger issue we simply can't identify but with the jeep all buttoned up, the new Mopar TOB & MC/Slave installed and my wallet quite a bit lighter the clicking sound when pressing and releasing the clutch returned after about five minutes of driving. Jeep is going back to the shop tomorrow. Good think I didn't return the rental today.

If all this isn't enough my daughters Liberty developed a loud front end clunk... it's going in the shop as well.

I'm kinda done with the Jeeps...

 

[machoheadgames]

I don't know if it's better or not, or if I have a bigger issue we simply can't identify but with the jeep all buttoned up, the new Mopar TOB & MC/Slave installed and my wallet quite a bit lighter the clicking sound when pressing and releasing the clutch returned after about five minutes of driving. Jeep is going back to the shop tomorrow. Good think I didn't return the rental today.

If all this isn't enough my daughters Liberty developed a loud front end clunk... it's going in the shop as well.

I'm kinda done with the Jeeps...

Can you elaborate on the clicking sound? Is it a continuous sound or just a minor clunk when you change status? (Press pedal vs let go of pedal)

 

[MikekiM]

Can you elaborate on the clicking sound? Is it a continuous sound or just a minor clunk when you change status? (Press pedal vs let go of pedal)

Press the clutch and it clicks.
Let it out and it clicks again.

Audible and tactile.

Running or not.

In gear or shifting between gears.. absolutely fine.

I'd like to say it's minor.. but considering how this recent fiasco started the same way and ended with me stranded (again) it's hard to say minor.

 

[06TJ35's]

I been having my national throwout bearing for about 6 years.

 

[TheBoogieman]

Mopar = Luk. The composite TO bearings are equal to the metal ones in failures, according to Luk. They informed me that the main difference between the two is the damage done when the metal ones fail. Like @jeepguy03 stated, it's not the brand as much as poor quality control. When I order Mopar parts, I return any made in China as opposed to Mexico. I have bad luck with Chinese made parts.

 

[MikekiM]

Mopar = Luk. The composite TO bearings are equal to the metal ones in failures, according to Luk. They informed me that the main difference between the two is the damage done when the metal ones fail. Like @jeepguy03 stated, it's not the brand as much as poor quality control. When I order Mopar parts, I return any made in China as opposed to Mexico. I have bad luck with Chinese made parts.

One step ahead of you...

 

[machoheadgames]

Mopar = Luk. The composite TO bearings are equal to the metal ones in failures, according to Luk. They informed me that the main difference between the two is the damage done when the metal ones fail. Like @jeepguy03 stated, it's not the brand as much as poor quality control. When I order Mopar parts, I return any made in China as opposed to Mexico. I have bad luck with Chinese made parts.

In my experience, Mopar is not Luk on the throw out bearing. I’ve had them all in my hands and they are different.

 

[User4574]

No idea who makes it, but it's been the same part number for 30 years. I have witnessed Luk metal, Luk plastic, National, Mopar, and SKF in person. Luk metal was similar to the Mopar but they did have a few small differences. SKF looked very different from the rest, hard to explain but the pics online can show it. National looked similar to Luk metal and Mopar, but it didn't feel as good in rotations and the pressure plate finger surface could move around a bit more.

Since the original part number remains unchanged and available for purchase, I think Mopar is the best bet.

Water pumps are different because they have had a number of part numbers for those over the years and aside from the actual originals, have had very sketchy track records.

I put in SKF about 4 years ago. Didn't notice any significant differences in look. Has functioned as expected no issues.

 

[machoheadgames]

I put in SKF about 4 years ago. Didn't notice any significant differences in look. Has functioned as expected no issues.

You might have got a different one than me. The one I received definitely looked different than anything else I had seen before. I only bought that one out of curiosity to compare, I didn't need it so I didn't use it. I've used SKF products with success before, so I bet it would have been fine.

 

[lBasket]

When I was putting my MR2 drivetrain together it was also common opinion that all TOBs are junk and I was better off using the OEM one still in the transmission instead of the one that came with my clutch kit