Tell me why I need FM in my front veri loc with Quadra drive - JeepForum.com
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Unread 06-08-2013, 11:41 PM   #1
Idano12
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2004 WJ 
 
Join Date: Apr 2013
Location: Santa Teresa, NM
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Tell me why I need FM in my front veri loc with Quadra drive

When I'm in 4 wheel high, 100 percent of the torque goes to the rear until both rear wheels slip, then it transfers power to the front. When I'm in 4 low it splits 50/50.
Why do I need to put friction modifier in the front? I live in an area that gets maybe 3 days of snow every three to four years, if I'm in conditions that require the front to kick in, I want the front end locked up as tight as I assume a vari loc will lock up.
My last 4X4 was a Yota PU with a Detroit Locker in the rear and a TRD limited slip in the front. I get that I had locking hubs and didn't have to deal with the front being locked up during normal driving but, my quadra drive doesn't lock the front up either when I'm in 4 high and in situations I wouldn't have had the Yota hubs locked in anyway.
I get the crab walk potential and the go forward steering that you encounter with a good limited slip in the front and I don't think it's too much of a problem compared to having a looser limited slip when you need real 4 wheel drive.
I'm changing my gear oil and transmission fluid tomorrow, give me one good reason why I should to put FM in my front differential ?

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Unread 06-09-2013, 01:25 AM   #2
pinky2252s
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Quote:
Originally Posted by Idano12 View Post
When I'm in 4 wheel high, 100 percent of the torque goes to the rear until both rear wheels slip, then it transfers power to the front. When I'm in 4 low it splits 50/50.
Why do I need to put friction modifier in the front? I live in an area that gets maybe 3 days of snow every three to four years, if I'm in conditions that require the front to kick in, I want the front end locked up as tight as I assume a vari loc will lock up.
My last 4X4 was a Yota PU with a Detroit Locker in the rear and a TRD limited slip in the front. I get that I had locking hubs and didn't have to deal with the front being locked up during normal driving but, my quadra drive doesn't lock the front up either when I'm in 4 high and in situations I wouldn't have had the Yota hubs locked in anyway.
I get the crab walk potential and the go forward steering that you encounter with a good limited slip in the front and I don't think it's too much of a problem compared to having a looser limited slip when you need real 4 wheel drive.
I'm changing my gear oil and transmission fluid tomorrow, give me one good reason why I should to put FM in my front differential ?
Well uh, if you want the clutches to work you need to put FM in it. Not really sure why its such a problem, its not very expensive and you only need like 3 ounces of it. I dont think you understand how this system works, go to wjjeeps.com and read up on the quadra drive system.

Long story short, you are going to blow the clutches out if you dont put FM in the front differential. Then you will just end up with an open diff...
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Unread 06-09-2013, 01:27 AM   #3
alfaitalia
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Because Jeep said you do.....they built it and they should know! But seriously if you don't put it in you will almost certainly have groaning noises and crabbIng when turning sharp as the varilock struggles to slip like it needs to when one wheel has to travel further than the other (as happens in a sharp turn).
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Unread 06-09-2013, 03:05 AM   #4
ADragg
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I'm pretty sure it will bind like hell if you don't use it, before ruining the clutches, of course. Order some Redline (I think it's the 75w-140) or Amsoil Severe Gear if you want good diff fluid that will already be pre-mixed with the correct amount of Friction Modifier. Otherwise you'll have to add FM and then test out whether or not you get binding, ad more FM, and so on. It's a good system that will treat you right if you tread it right, and it NEEDS FM. Get your Jeep some quality Redline.

By the way, I'm surprised to say I've never heard of Santa Theresa, New Mexico. I thought I'd been to or at least heard of every town/city in New Mexico, as I spent the first 20 years of my life there, growing up in Albuquerque. I've (of course) heard of Santa Fe, but not Santa Theresa. I know Las Cruces, Grants, Farmington, Cuba, Chama, Taos, Las Vegas (NM), Alamosa, Alamogordo, Silver City, Carlsbad, T or C, etc, etc. But never heard of Santa Theresa!
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Unread 06-09-2013, 10:09 AM   #5
rm2001wj
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Vari-Loc differentials and the NV247 transfer case all use a geroter pump/clutch pack system which tries to lock whenever there is a difference in rotational speeds of two shafts (axle shafts for differentials and drive shafts for the transfer case). When driving, any turn that you make causes the axle shafts on the differentials and the drive shafts on the TC rotate at slightly different speeds, that happens whether or not there are slippery conditions.

So, when turning the the QD differentials and TC try to lock up. But, they can't because the pressure produced by the gerotor pumps is not large enough due to the relatively small differences in rotation speeds of the shafts. However, pressure on the clutch packs does produce clutch chatter The correct amount of FM allows slippage in the differential clutch packs at small differences in axle shaft (or wheel) rotational speeds. The Mopar NV247 TC lube is formulated with the correct amount and type of FM in order to allow some clutch slippage at small gerotor pump pressures caused by small rotational speed differences of the drive shafts

Bottom line is QD needs FM in the differentials and Mopar NV247 TC lube regardless of road conditions unless all your driving is done in a straight line. It is also true that too much FM does not damage anything, but it allows so much slippage that the clutch packs are completely ineffective.
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Unread 06-10-2013, 07:57 AM   #6
fastrr
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I used Valvoline synthetic with about ounce and a half of the Mopar friction modifier in my front differential. I wanted to use as minimal as possible to get the diffs to lock up as quickly as possible. I believe this is about the minimum to run as I have no clutch noise except in cases where I have the steering turned all the way and am on dry pavement. The noise is very minimal, almost more of a vibration then noise.

I have yet to do the rear as I wanted to get the front dialed in first.
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Unread 06-10-2013, 08:23 AM   #7
lazyWJ
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Try it with no FM. It will chatter like a ***** though. Add just enough FM to make the chatter stop, as fastrr says. Many people have found the factory recommendation is too much and impairs the ability of the axle to "lock".
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Unread 06-10-2013, 11:08 AM   #8
Cirruslydakota
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Ever check the price for a replacement vari-lok assembely? You cant just rebuild them and putting no FM in there is worse than too much. Add the FM in there until the chatter stops. But if you dont want to thats fine, ill take your vari-lok D30 and you can have my open D30.
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