Finishing up 8.8 install in my TJ?

jds97Wrangler

jds97Wrangler

Active Member
Joined
Oct 19, 2008
Location
Mccleansville, NC
I finally finished installing the 8.8 in my Tj and every thing seams ok. Nothing appears to be binding and everything is working properly but I am having a severe vibration when I accelerate.

The pinion angle appears to look good but this is a similar vibration I got when I put the 4" lift in. Once I installed the transfer drop kit the vibration went away. What would be causing it now? It is only under acceleration once up to speed and I let of the gas it is fine.

I do have adjustable upper and lower control links so if it is pinion angle I should be able to adjust it.
 
When you installed the 8.8 did you take the transfer case drop out? If you dont have a SYE, you need to keep the trans drop. If that hasnt changed, check U-joints on rear drive shaft, mine were bad and caused bad vibrations at about 25mph
 
devlsh1 said:
When you installed the 8.8 did you take the transfer case drop out? If you dont have a SYE, you need to keep the trans drop. If that hasnt changed, check U-joints on rear drive shaft, mine were bad and caused bad vibrations at about 25mph
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I kept the transfer drop in but I beleive your right about the Ujoint I kept the old U joint and just added the 8.8 flange. I think I'll go pick up a new ujoint tomorrow before I do anything drastic.

One other thing this has a limited slip differential I drained the oil and replaced it with new. On the case it recomends 75-140 synthetic so I put Mobile Ones synthetic in it. Some one mention to me that when you drain the oil on a limited there is a "stinky" additive you have to add. Is this something I need to do if I am running the synthetic.
 
jds97Wrangler said:
I kept the transfer drop in but I beleive your right about the Ujoint I kept the old U joint and just added the 8.8 flange. I think I'll go pick up a new ujoint tomorrow before I do anything drastic.
One other thing this has a limited slip differential I drained the oil and replaced it with new. On the case it recomends 75-140 synthetic so I put Mobile Ones synthetic in it. Some one mention to me that when you drain the oil on a limited there is a "stinky" additive you have to add. Is this something I need to do if I am running the synthetic.
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If it helps you any, I installed my 8.8 on my TJ with a 4" lift with a t-case drop and no sye. It didn't work out well. I had vibes and had to bite the bullet and do the SYE. The pinion on the 8.8 is lower than a D35 and the snout is a tad longer. I've not known anyone that was able to get away without the SYE when they installed the 8.8.
 
Cperry said:
the synthetic take splace of the additive, if you ran regular you would need to put in the additive.
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Not always we've had customers come in after someone else changed there gear oil with a gowning noise on turns and all we do is add limited slip modifier to it noises are gone.
 
I ran over 1.5 years after my 8.8 was installed with stock drive shaft and no SYE with issues. 4in Rough Country lift and trans case drop, and adjustable UCA's.
 
devlsh1 said:
I ran over 1.5 years after my 8.8 was installed with stock drive shaft and no SYE with issues. 4in Rough Country lift and trans case drop, and adjustable UCA's.
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Sounds like you ran the exact same setup I am running. I believe I made the mistake of pinching pennies in a place where it would have been about 10 bucks more. I didn't replace the Ujoint I just put the 8.8 flange on my old one.

I'll update after I get the new Ujoint installed, it is sad I replaced every thing on the axle including all breaks and new brackets. But I decided to pinch pennies on the cheapest part to replace.
 
JC said:
I always use the additive with LS diffs no matter what.
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I don't have any issues with turning it is straight line acceleration from 25 to about 40 after that it is find. It is not really a vibration it is a major shake. When I let of the gas it goes away and once I am above 40 it does fine.
 
rob92xj said:
X2 I don't care what the bottle might say, better safe then sorry.
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Well I cut one corner it it bit me a $13.99 part was causing all issues I replaced the U-joint and now it rides great no vibrations and it drives straight so I guess I welded everything in properly. We will see the first time ont he trail how well I welded it. Which is great because I was really looking forward to camping easter weekend and I wanted my jeep ready.

Just a side note I contacted Mobile on their 75-140 synthetic and they informed it has all the friction additive the ford 8.8 needs. Only under extreme circumstances they recomend adding any after market friction additive. I guess that is why it is $18 a quart compare 5.99 a quart for regular 75-140.
 
jds97Wrangler said:
Just a side note I contacted Mobile on their 75-140 synthetic and they informed it has all the friction additive the ford 8.8 needs. Only under extreme circumstances they recommend adding any after market friction additive. I guess that is why it is $18 a quart compare 5.99 a quart for regular 75-140.
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All the 75W140 gear oil we use is made by Mobil and we still add the friction modifier to the axle if not most of our limited slips groan and chatter on turns the Quadra drive system will have a Grand Cherokee come to a stop when turning if left without it long enough. Our parts dept charges about $25 a qt for it too.
 
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