87 K5, 10 bolts. Just got back from the local 4x4 shop after installing a tuff country 2.5” lift, 4.11 gears, ARB lockers and 33x12.50x15 tires. The drive shafts both look like they are now extended about an inch further than stock. Driving above 40mph, let off the gas to coast, and get an sound that I can only compare to a manual trans bad throw out bearing. Definitely something rotating. I’ve put the thing on stands, checked everthing by hand for slop. Seems solid. Is this a by product of the rear drive shaft not being seated as far as it used to be in the transfer case? I seem to remember a similar problem in a CJ7 I had many years ago. This is my first K5, so I’d be interested in your experience. Thank you!
CK5
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Driveline after 2.5” Lift
- Thread starter kyalbert
- Start date
Did you go with blocks or new springs for the rear? Sure sounds like your pinion angle is out of spec. Post some pics of your rear drive line.
Also remember that new gears have to be broken in with a few heat cycles. Hopefully that was done.
Also remember that new gears have to be broken in with a few heat cycles. Hopefully that was done.
Agree, sounds like a pinion vibe to me.
Springs all the way around. Talked to the guys at Tom Woods, they gave me some alternative test procedures. With the thing off the ground, everything in neutral, I found that tailshaft of the transfer case has quite a bit of slop. Interestingly, no slop between front and rear drive shafts with the thing in four high. This would indicate the chain is ok. Now to decide on a full rebuild, or tail shaft only.
Slip yoke eliminator, and new rear drive shaft
Most likely the route I will take. What’s another grand
Well they are the same size as many pleasure boat. Break out another thousand
Impossible. How are you checking this?
When you say "a lot of slop", can you put a number on it? There will always be some.
Still, the new noise on coast is most likely the wrong pinion angle. It's normal, because the lift has changed the geometry. A good 4x4 shop would have expected it, checked the angles and recommended the proper shims for you. It would have saved time if they did it then.
Go get an angle finder (there's also an app for some phones) and measure the tailshaft and pinion angles. When you shim that difference away (actually set the pinion 1 degree higher), the noise will go away. Then decide how much work the transfer case needs.
Sure sounds like a driveline angle issue to me.
I’m kinda surprised and disappointed a 4x4 shop went through all that work and didn’t make any effort to check them at all much less drive the truck after completing.
It’s pretty obvious when it’s not right. Nothing against you not doing it yourself but those guys are the pros and should know well enough to at least road test and make sure all is good.
Typically only going 2.5” does not cause the issues that a 4” kit does or going to a shackle flip. So it’s probably only going to need a pinion angle adjustment. A sye isn’t a bad idea but it’s not really common to require one at that level.
I’m kinda surprised and disappointed a 4x4 shop went through all that work and didn’t make any effort to check them at all much less drive the truck after completing.
It’s pretty obvious when it’s not right. Nothing against you not doing it yourself but those guys are the pros and should know well enough to at least road test and make sure all is good.
Typically only going 2.5” does not cause the issues that a 4” kit does or going to a shackle flip. So it’s probably only going to need a pinion angle adjustment. A sye isn’t a bad idea but it’s not really common to require one at that level.
Thanks to everyone for the advice. I’ve never had anyone do work for me before, but there comes a time in one’s life where the desire to lay in cold concrete and lack of time merges with the financial ability to pay someone else. It’s difficult, because part of the joy of building your own rig is knowing every noise it makes and understanding exactly where a new noise is coming from. Tom Woods people are the best. I’ve got my SYE kit and drive shafts, and 8 degree shim kit. The measurement instructions they have are awesome and yes, driveshaft angle is the big problem.
On the “impossible” note to check chain stretch in NP208. Four wheels off the ground. Trans in neutral. Xfer case in four high. One hand on front driveshaft, one hand on read drive shaft. Rotate back and forth. Feel slop? Chain stretched. Don’t feel slop, chain good. Simple method I was taught many years ago.
Also, I just want to make sure the 4x4 shop sold you the right lift, as Tuff Country only makes a 2", 3", and 4" kit for these trucks.
Rough Country does make a 2.5" kit, but it should of cost you considerably less.
And not to get into the weeds too much but only 4.10's are available for 10 bolts, not 4.11's. Not much difference obviously, but now I'm afraid the shop misinformed you.
I understand dude. After getting my ass kicked swapping front springs on mine today I’d have second thoughts about farming it out. My concern was over the lack of follow through on the work they did. If I’m paying they better damn well do the job all the way.
I’ve been raked over the coals when my techs didn’t. So I had to get involved and smooth things out. They should have caught this prior to you taking it home. Plain and simple.
88Silverado
1/2 ton status
Can you provide more information on this "get an sound that I can only compare to a manual trans bad throw out bearing" This only happens when you are off the gas and decelerating? Is it a whining sound that decreases as you drop speed? Your not mentioning a vibration which would be more a pinion angle. I'm wondering if its a setup issue since you had gears changed. If its whine on decel, sounds like they didnt get the pinion depth set properly on the ring gear on the coast side. Try taking it to a differential shop and have them take it for a test drive for a second opinion before tearing things apart.
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I’ve heard pinion angles make the exact noise he is describing without much vibration if any at all, but from the sounds of this shop it may not be a bad idea to have the gears checked.
Just keep in mind that you will also feel a little bit of play in the engagement collar for the front drive.
And I have never myself seen a chain failure on a 208 or 241 that wasn't caused by lack of maintenance. So I personally wouldn't replace a chain unless it was loose enough to contact the case or has an audible sound of binding under load. I have heard this from a 241 with over 250K on it, that also had drop in lockers in both axles.
Who do you recommend in the Los Angeles area?
how did i not see / know you were in the LA Area? not sure of a local company or shop qualified to do the work - in the past have been anal about nobody touching my truck but myself... If you find a place i would be interested to know.
I just made a move to a small apartment and currently have no workspace in my 1 horse garage, so not going to be much help, but I did a SYE in my driveway a few years ago- basic hand tools and snap ring pliers.
-edit- that was on a 241 though
I just made a move to a small apartment and currently have no workspace in my 1 horse garage, so not going to be much help, but I did a SYE in my driveway a few years ago- basic hand tools and snap ring pliers.
-edit- that was on a 241 though
