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Discussion Starter · #1 ·
I just got home from lifting my 85 blazer and i lifted it 4inches frt and rear. My ujoints in the rear are pretty worn and may be the sole source for the vibration?? I have a vibration between 30-50km when accelerating, what might be the cause? also my pro comp kit came with tapered 4in blocks for the rear and the shaft angle really doesn't look all that bad. I will be droping the transfer case 1inch tomorrow so this may cure it but has anyone else experienced this problem??

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Project MudhuckerII is now underway and movin ahead
 

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Hehehe I just finished lifting mine 4 inches last night. Except I did it the cheapo way and went with no name blocks and re-arched the front springs. But I have the EXACT same problem. Does your only vibrate when under light or medium acceleration as well? I find if its stomped its usually fine, but flooring it off the line to avoid vibrations won't help my gas milliage.

I'm hoping if I replace all the u-joints I should be fine.
 

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Yeah, you may want to try replacing your universals first. Chances are they have been used to operating at a certain degree with wear, and due to the change in angle of operation, you are experiencing a vibration. Lowering you transfer case will help, if you think that the vibration is from your front driveshaft. Good rule of thumb is to ensure your universals are running as close to parallel in relationship to each other.

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I've used up my sick days, so I'm calling in dead, and I'd like three funeral days along with my weekend off.
 

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With only a four inch lift, dropping the t-case and replacing the u-joints should be enough

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80 Cj5, Met.Grey,360amc, Swampers, Custom 5in. lift, Warn winch,
92 XJ Blue6/6.5" Rubicon, 33" Swampers, engine build up in the works
 
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When my buddy did his 4" in his Jimmy, he had to drop the T-case 1" and lengthen the driveshaft to kill the vibration. The slip yolk was sitting too far out of the T-case and this is what was causing the vibration.


[This message has been edited by JC BAZINET (edited March 15, 2002).]
 
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A different buddy I helped put a Procomp 4" in his 79 Blazer. The only problem he has is dropping the rear drive-shaft. He keeps eating u-joints. He lengthened the driveshaft but never dropped the T-case like I told him. Last time I talked to him 3 u-joints later, the truck was off the road, and guess what... he's dropping the T-case.
 

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Dropping your transfer case will only solve your front end vibrations, not the rear end. Mudhucker, I found a good article about this if you're interested. Very informative and deals with a variety of driveline situations. It's not on the web, but saved on disk. You got no addy so I can't send it to you.

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I've used up my sick days, so I'm calling in dead, and I'd like three funeral days along with my weekend off.
 

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Discussion Starter · #9 ·
[email protected] that article would be much appreciated. Thanks. Yeah my vibration is only under 50 and over 30 when slowly starting or slowing down?? sounds pretty common, i'll mess with it a bit tomorrow, but i think i'm gonna look for a way to put a cv joint in the top of the shaft going into the t case. That was a long day of work?? i worked from 730 to 5 then i went home and ate back to work by 8 and doing the lift til 2, but it was totaly worth it, now i just have to ditch the studded 235/75r15 winters and put on the 35's when i get the money

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Project MudhuckerII is now underway and movin ahead


[This message has been edited by Mudhucker (edited March 15, 2002).]
 

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Hey Mudhucker

Your problem is very likey weak u joints that you finished off with the new drive shaft angle. If you are running the stock 10 bolt with its 3.07 or 3.08 gears and 35" tires you will soon be an expert at changing u uoints.(Ask me how I know)I always carried a spare when I had the 10 bolt(an axle woudnt be a bad idea either)and I should probably have a spare for my new setup too.
Good luck
Ken

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Discussion Starter · #11 ·
cool thanks i'll be doing all the touch ups on sunday, u joints, transfer case drop, brake line relocation, etc

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Project MudhuckerII is now underway and movin ahead
 

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Hi, I also just lifted my suburban, 4" procomp lift and rearced my rear springs, the rear came up pretty high and i have a vibration problem as well (and my front driveshaft isnt even in!) I was told it is probably the driveshaft angle just as others here have mentioned. The vibration only happens under 60 after I let go of the accelerator, anyhow... good luck!

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1989 SUBURBAN 4x4 5.7L 4" Lift - BFG's
1988 Toyota 4Runner
 

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Discussion Starter · #13 ·
this really sounds common?? yet when i've driven my friends 89 K5 it drives like a car with a 4in susp lift and 35's???

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Lowering the T-case isn't going to affect front driveline at all. It isn't turning...

The problem with most lifted K5's is the fairly short rear driveshaft and the slip yoke at the T-case. A lot of slip yokes are a bit worn and some will bind a bit at more extreme angles. A slip yoke is designed to move in and out, it does not handle being vertically loaded by the more severe angle. Lowering the T-case is usually enough to cure the vibes. The best is to convert to a fixed yoke and run a CV shaft...but that can be expensive.
Also before you spend the dough for a CV shaft you might consider swapping in a 14 bolt rear end. 10 bolts are fine for street tires but not much more than that. A 10 bolt front will work OK up to 35" tires and can be converted to 8 lug to match a 14 bolt quite easily.
The combo I run right now is D44 front, 14 bolt FF rear, 4" lift (1" body lift) and 36" tsl's. I have no vibes and regularly run 75 mph on the freeway. I do run a fixed yoke 205 and a 4 speed though so the rear shaft angle isn't quite as steep.

Rene



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Discussion Starter · #15 ·
cool, i was talking to trucks plus in kamloops and they said to drop the transfer case and that'll cure it and that doing the 3/4 ton axle swap is actually very easy and totally worth while, so i'll be waiting til summer to get them hopefully before i header down south

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Project MudhuckerII is now underway and movin ahead
 

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Well I'm going to replace all my universals anyways, and I guess I'll probably look into lowering the t-case as well. I have fulltime anyways so.

Problem is I had a little mix up with the angle grinder and my rubber break hose at school. Half an hour after the last class before spring break. Grinding the frame to weld in my break line brackets, cut the hose. Said "**** it, I'm doin this all now". Went to the otherside to undo the hose, and the wrench slipped off the inside and I didn't know, twisted up the main line and broke that. At any rate, the shop teacher wanted to leave, so my truck is locked in the school over spring break until further notice. We're hoping we can find someone to let us in so we can drive it home without front brakes and finish the work.
 

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Discussion Starter · #18 ·
hahahahah welcome to my world
it seems like every single time i work on my truck i find something else that doesn't look right and out comes another brown bill
this damn truck sure is cuttin into my party money???? I just keep thinkin of what it'll be like drivin around this summer with my porsche blue paint 7in lift And 37 in hummer tires and it makes my think about other things than the costs involved


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Project MudhuckerII is now underway and movin ahead
 

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Sorry I haven't sent the info earlier guys, anyways, for anybody else who would like this article, leave your e-mail addy here. I will send it off
NOTE!!! It' a fairly large file, so please be patient. I'll be sending it from a [email protected] address, so please don't hit the stop button thinking that it's spam. heh heh.

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I've used up my sick days, so I'm calling in dead, and I'd like three funeral days along with my weekend off.
 

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Yeah it'll all pay off in the summer. Top off, doors off, warm weather, parties at the beach or in the boonies. Ooohhhhh yeah. Cept ya know, I'll only be riding with 4 inches of lift and 33s, and chances are my K5 is WAY uglier.
 
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