Suspension Question...

[JonnyBlaze]

I have Fabtech 6" lift, but my factory air ride still works. How and why is that? Lol. I know, dumb question, but I just bought it and am new to the Expy world. Also, what can I do to stiffen up the rear so I dont get so much body roll?

And I read some info on the Fabtech lifts and states that the kits can cause some vibration and to buy an add on kit for the driveshaft or something. Well, I do feel some vibration sometimes like if I going up hill or accelerating, but is that from the lift kit? If so what do I need?

 

[nvycrmn]

lets start with the air ride. does the kit you have still keep the air bags in the rear or do you have springs in the back?
as for body roll, you will have a little no matter what cuz of the size of our vehicle. but if it gets too bad, there are some things you can do to make it stiffer. some people will chime in soon im sure to tell you how.
as for the vibration, this could be from a few things. if you have the limited slip, could be clutch packs or could be you just need to change your rear diff fluid and put more friction modifier in. if it is from the front, could be the front driveline...

 

[JonnyBlaze]

I have air ride all the way around. I think the vibrations is coming from the rear. And I was thinking about changing my diff. oil anyway. Anyone know what weight of oil andhow much and what kind of friction modifier to use?

 

[panda24619]

theres a thrend that nvy did somewhere on here about his rear diff. i think its 75/120 dont remember. look in your owners manual itll be in there. hell post something about it cause he knows more about it then me.

 

[Rumrunner]

I was under the impression that my 2000 EB with air ride couldnt have a susp lift put on it?

I was going to body lift but if I can sky rocket this thing.... Could anyone point me in the right direction?

Sorry for hte threadjack.

 

[JonnyBlaze]

I have air ride on allfour corners and a 6" lift.

 

[Racenut]

I have air ride all the way around. I think the vibrations is coming from the rear. And I was thinking about changing my diff. oil anyway. Anyone know what weight of oil andhow much and what kind of friction modifier to use?

For the gear oil it takes the 85w140 and if you use a full synthetic like Royal Purple you do not need to add any of the friction modifier, and if I remember correctly it uses just under 3qts. I know I can get the Royal purple here for 17 a qt so your looking around $60 with tax. I know alot of people down here in the southwest that where having the vibration from the factory limited slips from expy's to diesel trucks and they along with me will never go back to regular gear oil and additive.

 

[JonnyBlaze]

For the gear oil it takes the 85w140 and if you use a full synthetic like Royal Purple you do not need to add any of the friction modifier, and if I remember correctly it uses just under 3qts. I know I can get the Royal purple here for 17 a qt so your looking around $60 with tax. I know alot of people down here in the southwest that where having the vibration from the factory limited slips from expy's to diesel trucks and they along with me will never go back to regular gear oil and additive.

SO you recommend Royal Purple and no modifier?

 

[nvycrmn]

no! if you read the manual, it tells you that you have to run synthetic fluid WITH friction modifier. if you dont run the modifier, you are going to eat through the gears. look under the how-to section for the write-up on the rear diff change. it should tell you in your manual what you are supposed to use.

 

[Racenut]

Exactly the full synthetic lubricates the clutchs in the limited slip without needing to add any modifier to it.

 

[JonnyBlaze]

Ummm........

 

[KWT2000]

Exactly the full synthetic lubricates the clutchs in the limited slip without needing to add any modifier to it.

NOT TRUE!!!! all limited slip diffs require a friction modifier!!! ford and chrysler use full synthetic gear oil while gm`s use syncromesh fluid but none the less use the friction modifier so you dont eat the clutches up and in the ford 9.75 they use organic clutch material not as for giving as the ceramic clutch in the 8.8

 

[Racenut]

no! if you read the manual, it tells you that you have to run synthetic fluid WITH friction modifier. if you dont run the modifier, you are going to eat through the gears. look under the how-to section for the write-up on the rear diff change. it should tell you in your manual what you are supposed to use.

This is straight from the ROYAL PURPLE website.
http://www.royalpurple.com/gear-oil.html

Max-Gear is an ultra-tough automotive gear oil. It’s designed to maximize power and provide unsurpassed protection to heavily loaded gears. It makes gears run smoother, quieter, cooler and longer without overhauls.

Max-Gear outperforms other gear oils because it combines the highest quality synthetic oils with Royal Purple’s proprietary Synslide additive technology.

Max-Gear is recommended for use in truck, motor home / RV, and automotive front or rear differentials, manual transmissions, and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary.

I have been running it along with a bunch of others hear in the southwest with no problems what so ever to our limited slip rear diff. It actually runs smother than other synthetics with the modifier additive.

 

[Racenut]

NOT TRUE!!!! all limited slip diffs require a friction modifier!!! ford and chrysler use full synthetic gear oil while gm`s use syncromesh fluid but none the less use the friction modifier so you dont eat the clutches up and in the ford 9.75 they use organic clutch material not as for giving as the ceramic clutch in the 8.8

I'm sorry in this I should have put:

Exactly the ROYAL PURPLE synthetic lubricates the clutchs in the limited slip without needing to add any modifier to it.

I have done my home work as well and ROYAL PURPLE already has the friction modifiers in it. See the reply to nvycrmn with the information from the royal purple website.

I am not trying to be an a** on here, but I also do my home work before I do anything to my vehicle and I dam sure try to make sure that anything I post is accurate.

 

[nvycrmn]

okay, i gotcha. i thought you were talking about ANY fully synthetic gear oils. my bad.

 

[KWT2000]

im glad its working for you as for me i wouldnt trust it or recomend it either way with the modifier being around $5 just not worth the chance

 

[panda24619]

yeah i wouldnt trust it with out it. i need to change my fluid so for an extra $5 im getting it.

 

[Racenut]

I had been having the same problem with the chattering and had changed the gear oil with some Valvoline synthetic and two of the 4oz bottles of modifier and the rear end still chattered. After talking with a few people and doing some research I decided to go ahead and try the Royal Purple and now I am glad I did, I do not have any chatter coming from the limited slip now even when towing.

 

[nvycrmn]

hmm, i will have to try it then cuz i used the valvoline and 2 bottles of friction modifier and i still have chatter when turning from a stop.

 

[Racenut]

hmm, i will have to try it then cuz i used the valvoline and 2 bottles of friction modifier and i still have chatter when turning from a stop.

That is exactly what mine was doin and even worse with a trailer, and it was ****** me off. But it made a night and day difference in mine, I was skeptical at first but it worked for me so hopefully it will do the same for you.