Transfer Case: Harmonic Balancer or Not?

Slaughterrt

Slaughterrt

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Apr 29, 2020
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Forked River, NJ
Picking up a new used transfer case to swap in…my current TC has a harmonic balancer on it. Does the new used one NEED one? I haven’t ordered it yet, but most of the transfer cases I have seen do not have the harmonic balancer.

Is it necessary?

Thanks.
 
Slaughterrt said:
Picking up a new used transfer case to swap in…my current TC has a harmonic balancer on it. Does the new used one NEED one? I haven’t ordered it yet, but most of the transfer cases I have seen do not have the harmonic balancer.

Is it necessary?

Thanks.
Click to expand...

They added the balancer in 2003, so older cases don't have it.

I'm fairly certain you won't find anybody that can tell you the consequences of NOT using it, and many of us have installed slip yoke eliminators which eliminate any provision for using it.

But I can't help but consider that it cost Jeep money to buy the balancer and install it, and they don't just throw parts onto vehicles all willy nilly without having identified a need for said part. If I was in your position using a stock case and could use the balancer, I would keep it and put it on your new one.
 
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Slaughterrt said:
Picking up a new used transfer case to swap in…my current TC has a harmonic balancer on it. Does the new used one NEED one? I haven’t ordered it yet, but most of the transfer cases I have seen do not have the harmonic balancer.

Is it necessary?

Thanks.
Click to expand...

Jeep didn’t just throw money away. I suspect the reason for it relates to the NHV story that has unfolded. Now that many have replaced their slip yokes with fixed yokes and typically regeared deeper, these NHV accounts have increased. Of course, there is that one outlier of a stock rig, but I don’t recall if it had the balancer or not. If it’s got a balancer keep it. If not, it is what it is. Hopefully be fine.
 
Thanks for all the replies guys. Long story short, my rear output shaft on the t-case decided to liberate itself from my jeep, and took my rear driveshaft with it. So after a bunch of research, cost-wise it’s about the same to rebuild my t-case (plus buy the new output shaft and a couple of different tools) versus picking up a used transfer case. I know it’s not a super complex job to rebuild the transfer case, I just don’t have the time or space to do it right now. In my searches, the majority of the used transfer cases that I have seen online do NOT have the harmonic balancer. Was just trying to figure out how necessary it was. I suppose I could remove the old one and install it on the “new” transfer case.
 
Slaughterrt said:
Picking up a new used transfer case to swap in…my current TC has a harmonic balancer on it. Does the new used one NEED one? I haven’t ordered it yet, but most of the transfer cases I have seen do not have the harmonic balancer.

Is it necessary?

Thanks.
Click to expand...

I have a 2003 Sport TJ with an NP231 TC. I installed the SYE kit and a new rear shaft after rebuilding the TC and Rear End. What I am dealing with now is a low frequency vibration that starts around 50 mph. I read another post on this forum in which the poster postulated the theory that the vibration could be mitigated by changing the mass of the TC and Skid plate. So I bought a box of 1oz. wheel weights and have been applying them to the skid plate and the TC wherever I can. It is reducing the vibration but it has not completely gone away. I think the reason 03 Jeeps have the balancer is because of this issue.
The problem is that I cannot find a Harmonic Balancer for the TC. I think it would fix the problem. However, with the SYE kit installed adding one most likely means rebuilding the TC again. That is unless I can find one that is designed for the SYE kit installation.
You might want to add some density to your skit plate and TC housing is your not going to use the HB.
 
kleinsasser.62 said:
I have a 2003 Sport TJ with an NP231 TC. I installed the SYE kit and a new rear shaft after rebuilding the TC and Rear End. What I am dealing with now is a low frequency vibration that starts around 50 mph. I read another post on this forum in which the poster postulated the theory that the vibration could be mitigated by changing the mass of the TC and Skid plate. So I bought a box of 1oz. wheel weights and have been applying them to the skid plate and the TC wherever I can. It is reducing the vibration but it has not completely gone away. I think the reason 03 Jeeps have the balancer is because of this issue.
The problem is that I cannot find a Harmonic Balancer for the TC. I think it would fix the problem. However, with the SYE kit installed adding one most likely means rebuilding the TC again. That is unless I can find one that is designed for the SYE kit installation.
You might want to add some density to your skit plate and TC housing is your not going to use the HB.
Click to expand...

I don’t think there is a harmonic balancer for SYE’s.
 
06TJ35's said:
My 06 has a harmonic balancer. I’m doing a SYE this weekend and will be removing it.
Hopefully I can get it off.
Click to expand...

Use three M6x1.0 class 10.9 bolts at least 35mm long to walk it off. They'll press against the rear seal flange, which will be replaced anyway.

HB_bolts.jpg


HB_boltmarks.jpg
 
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Agreed. I am having good results from adding density to the skid plate. But the harmonic vibration is still present above 50. I think I will need to add weight directly to the TC housing to eliminate the HV. Any ideas?
 
kleinsasser.62 said:
Agreed. I am having good results from adding density to the skid plate. But the harmonic vibration is still present above 50. I think I will need to add weight directly to the TC housing to eliminate the HV. Any ideas?
Click to expand...

Have you tried adjusting your pinion angle? Maybe a degree or two up or down will eliminate the vibration.
 
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kleinsasser.62 said:
Agreed. I am having good results from adding density to the skid plate. But the harmonic vibration is still present above 50. I think I will need to add weight directly to the TC housing to eliminate the HV. Any ideas?
Click to expand...

What’s your pinion and shaft angles? Check both front and rear.

Rear pinion is ideally 1* lower than the shaft.
Front caster is more important than pinion angle, but if you’re chasing vibes set the pinion and driveshaft the same and see where you are. If the same, remove the front shaft. If they go away get front hubs.
 
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OldBuzzard said:
Probably because there is nowhere to stick it.

OEM shaft:

View attachment 490642

SYE shaft:

View attachment 490643
Click to expand...

Maybe we ought to petition one of the SYE manufacturers to make an output that would accept the damper and flange used on the Rubicon case, or a damper and flange that would fit on an SYE output. Then use a flange yoke on the front of the DS, like with the Rubicon.
 
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