Harmonic vibrations in Jeeps: A new theory (please read!)

StG58 said:
AX5 manual.

It's interesting that the four banger, with inherently more vibration than a six, and an AX5 transmission which is less stiff than the transmissions behind the six didn't get a harmonic balancer. The rest of the drive train is essentially the same except for minor details. The rest of the Jeep is essentially the same as well.
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Thanks once again for your valuable info. I forgot that you had the 2.5 engine.

Man, I wonder if we can create a table with 4 columns (engine, trans, axle gears, balancer) and try to fill out with a poll or something. Then try to see if there is a pattern as to which combo shows a problem after regearing. That's the scientist in me asking to collect more data :risas3:
 
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psrivats said:
Thanks once again for your valuable info. I forgot that you had the 2.5 engine.

Man, I wonder if we can create a table with 4 columns (engine, trans, axle gears, balancer) and try to fill out with a poll or something. Then try to see if there is a pattern as to which combo shows a problem after regearing. That's the scientist in me asking to collect more data :risas3:
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You could, and it would be worthwhile, but I couldn't get the crew to tell me how much their TJ's weighed when I asked. You might have better luck.
 
StG58 said:
You could, and it would be worthwhile, but I couldn't get the crew to tell me how much their TJ's weighed when I asked. You might have better luck.
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I can start with the service manuals first and see what I can find there.
 
Year: 2003
Trim: Sport, Dana 44/Dana 30, 3.73 gears
Trany: NV3550 5 speed
Curb weight: 3460lbs.
TC balancer: Yes

This is how it came out of the box broheems.
 
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bobthetj03 said:
Year: 2003
Trim: Sport, Dana 44/Dana 30, 3.73 gears
Trany: NV3550 5 speed
Curb weight: 3460lbs.
TC balancer: Yes

This is how it came out of the box broheems.
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Nice shot @bobthetj03, nice shot.

Year: 1999
Trim: SE, Dana 35/30, 4.10/4.11 gears
Trany: AX5 5 speed
Curb weight: 3300lbs. loaded for the woods and a full tank of gas
TC balancer: No
 
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Here is mine

Year: 2005
Trim: Rubicon, Dana 44/44, 4.10
Trany: 42RLE
Curb Weight: Except for tires and no rear seat, mostly stock. Guessing 3900lbs?
TC Balancer: Yes
 
I found more useful info on the internet and the damn frequency it was designed to correct (55 Mhz! that explains the drone and what we feel).
@Chris

https://forums.off-road.com/jeep-short-wheelbase/207298-harmonic-balancer-transfer-case.html

jjh40
"It was used for two reasons. It was to dampen a low frequency vibration coming from the T-case. If memory serves correct it is 55hz. It also takes the place of the tin washer in the slinger seal. the one that the flared rubber seal rides against. This damper is also used on some XJ's. It was designed by the Hillsdale Tool division of Eagle Picher Automotive, for New Venture Gear in Syracuse NY. I was the engineer that set-up the production line on this part. Two double spindle cnc lathes, and an assembly press to put the rubber in. Oh yeah, a vertical cnc machining center to drill and tap those dreaded puller holes. They were hard to keep in the right position because they are very close to the rim of the hub. I think I have a part at home, and I'm sure I have prints of it still. FYI, there is a very similar damper on Libertys also. I do not work for that company anymore. I may have a picture of the damper if I do a little digging. I'll post it if I find it."
 
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Here is mine

Year: 2004
Trim: Rubicon, Dana 44/44, 4.10
Tranny: 42RLE
Curb Weight: 3740 lbs. stock. Added Dirtworx bumpers, so maybe 50-60 lbs. added
TC Balancer: Yes

5 pages into the thread. Not any closer to wanting a regear.
 
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tworley said:
My dad always said "they came that way from the factory for a reason". Maybe hes on to something!
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My dad says turn it in after the 3 year lease ends and start over with a new warranty lol. I don't think he has had a car over 3 years since the early 2000's.
 
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More digging .. this has perplexed a lot of people even back in the day.

upload_2018-11-2_13-42-46.png



http://www.4x4xplor.com/SYE-CV.html
 
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psrivats said:
I found more useful info on the internet and the damn frequency it was designed to correct (55 Mhz! that explains the drone and what we feel).
@Chris

https://forums.off-road.com/jeep-short-wheelbase/207298-harmonic-balancer-transfer-case.html

jjh40
"It was used for two reasons. It was to dampen a low frequency vibration coming from the T-case. If memory serves correct it is 55hz. It also takes the place of the tin washer in the slinger seal. the one that the flared rubber seal rides against. This damper is also used on some XJ's. It was designed by the Hillsdale Tool division of Eagle Picher Automotive, for New Venture Gear in Syracuse NY. I was the engineer that set-up the production line on this part. Two double spindle cnc lathes, and an assembly press to put the rubber in. Oh yeah, a vertical cnc machining center to drill and tap those dreaded puller holes. They were hard to keep in the right position because they are very close to the rim of the hub. I think I have a part at home, and I'm sure I have prints of it still. FYI, there is a very similar damper on Libertys also. I do not work for that company anymore. I may have a picture of the damper if I do a little digging. I'll post it if I find it."
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Score! So, I wonder if the chain and planetary gear mods to the 231 would change the frequency enough to fix the issue?
 
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glwood said:
5 pages into the thread. Not any closer to wanting a regear.
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But if I were in your shoes and reading this thread, I would wait too!

I am giving this all I can at the moment. I really wish I were more mechanically inclined like some of you guys here on the forum.
 
StG58 said:
Score! So, I wonder if the chain and planetary gear mods to the 321 would change the frequency enough to fix the issue?
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Who knows! Your post now makes me wonder if guys with Atlas transfer cases have these vibration issues after regear.

I asked to join that forum, awaiting account approval. I will contact that engineer and/or the company mentioned if it still exists.

We are trying to reverse engineer what Jeep figured out 20 years ago!
 
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I'm guessing going to the six planetary setup might (about $400 new) and the wider chain and sprockets might not (about $300 new). $700 to find out though.
 
This is from the 2003 FSM for the 231 TC. Looks like all manuals in that year have the damper, I need to check all years. Guessing the 32RH did not get it? Need to read more. I will post a nice table with the info I collect for all the years.

upload_2018-11-2_14-32-24.png
 
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@psrivats , I plan to have a lengthy conversation with Tom Woods, and will point them in this direction as well as question them about the balancer. They received my DS today, so I'll be expecting a call from them sometime next week, hopefully.
 
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