Big clunk, bump in tight turns sometimes!

THIS FORUM IS FOR ANY QUESTIONS ON THE 7.25" IFS FRONT DIFF, CV HALF SHAFTS AND FRONT DRIVE SHAFT.
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Topic author
spyboy
I am merely driving my van
I am merely driving my van
Posts: 15
Joined: Fri Dec 20, 2013 6:08 am
Location: New Orleans

Big clunk, bump in tight turns sometimes!

Post by spyboy »

2001 AWD when I bought had front drive shaft out but drove nice. Previous owner sworn he took out shaft for better mileage . Anyway I put back in and light stayed on and then went out and then came back on then...... Well I took to parking lot and tried tight turns. When light on no bump, clunk is really more like bump, light goes off clunk bump, .. No leaks I can see. Anyway would like to fix.. Also wondering how tall a tire I can put on with maybe a 2 inch lift.. Most worried in New Orleans about pot holes, off road mostly sandy areas to find fish or camp..slightly more clearance is good.. What about changing to 16 wheels, do they bolt on?thanks.. :usa:
2001 AWD Astro SLE, "too stock"

Captn. Crunch
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Re: Big clunk, bump in tight turns sometimes!

Post by Captn. Crunch »

Funny how swearing and p.o's seem to go hand in hand isn't it? If you are having issues with thumps and bumps after installing your front prop shaft, I would start with a thorough front end inspection. Re- introducing the preload from the transfer case might be aggravating worn out idler arms, ball joints etc...
As for 16s on your van GM only ran them for the last two years of production 03-05. Not only are the wheels taller they changed the bolt pattern from five to six stud. The fronts require you to change out the hubs to the six stud. The brakes were also beefed up and I don't know for sure if you can use existing calipers. Rears will mean changing axles to get your six studs and would probably be easier to change out the entire rear end. A lot of work for 1" but hey that's what we do here. I'm sure there are members here who will chime in with more info than I have provided but I think what I have stated is more or less accurate and if not that will be pointed out too!
There are lots of information available here about lifting your van with various body and suspension lifts and upping your tire size
Good luck with your van
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Captn. Crunch
I sleep in my van
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Re: Big clunk, bump in tight turns sometimes!

Post by Captn. Crunch »

Sorry- upon further review this topic of 16 inch wheels has already been addressed in the post converting 99 to six studs... In the driveline forum. Give that a read
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

LiftedAWDAstro
I have my van tatooed on my cheeks
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Joined: Sat Sep 09, 2006 3:35 pm
Location: New Haven, NY

Re: Big clunk, bump in tight turns sometimes!

Post by LiftedAWDAstro »

How is the fluid in the transfer case? Open the fill plug and take a sample. It should be a nice blue color. I bet it's never been changed. You will need 4 quarts of GM Auto Trak 2 fluid. You will want to change it out and put 2 quarts in. Hook up the front driveshaft and drive it a little bit and do some figure 8's in a parking lot. I would recommend doing it in a gravel lot if you have access to one. After putting a couple hundred miles on it, flush the fluid out again with the other 2 quarts and see if that makes the clunk/bump go away. It could be sticky clutches inside.

If that doesn't work, you should be able to remove the transfer case encoder motor and drive it that way and see if it still does it. I would think by removing the motor off the side it should free up the clutch inside but I am not 100% sure on that.

With a 2" lift you can run up to about a 29" tall tire with maybe minimal trimming. You can swap to any size wheel you want and you don't need to change bolt pattern. Yours has a 5x5 bolt pattern so look for 16" - 20" wheels in a style you want. Jeep wranglers of the recent era as well as Grand Cherokees from 99 to current also use the 5x5 bolt pattern and those wheels may fit.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy

Topic author
spyboy
I am merely driving my van
I am merely driving my van
Posts: 15
Joined: Fri Dec 20, 2013 6:08 am
Location: New Orleans

Re: Big clunk, bump in tight turns sometimes!

Post by spyboy »

Thanks just drove van and when it is cold not problem, when it warms clunks some times progressively worst only during almost to lock turns. Really think this might br the problem .. Thanks again.
2001 AWD Astro SLE, "too stock"
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