4wd bang

[chinweasle]

vehicle 1998 ZR2 Blazer

so I'm having this issue with my blazer... when in 4hi I'm getting a random bang noise, sounds metallic. Now, I've checked the fluid level in the tcase, the front ujoint, CV joints... everything looks fine. Only thing I haven't checked yet is the fluid in the front diff.... any ideas on what could be the culprit?

[PsychoticDeadGuy]

well, does it do it in 4lo? if not, then it has to do with your t-case, if so then its your front diff. try locking your hubs and driving in 2hi and see if it still bangs. It could be your front diff.

[chinweasle]

Originally Posted by PsychoticDeadGuy

well, does it do it in 4lo? if not, then it has to do with your t-case, if so then its your front diff. try locking your hubs and driving in 2hi and see if it still bangs. It could be your front diff.

no locking hubs... vaccuum set up.

I haven't tired it in 4lo.. mainly only time I notice it is when I'm going faster than like 10mph... and I never get going that fast in 4lo.

[senatorfrisky]

could be a broken tooth in your ring gear... or should i say... a tooth that USED to be in your ring gear!

[chinweasle]

Originally Posted by senatorfrisky

could be a broken tooth in your ring gear... or should i say... a tooth that USED to be in your ring gear!

I wondered about that, but, if it was a broken tooth wouldn't it be a more constant bang? and this is pretty loud also(similar to volume of when I grenaded my rear gears)...

[senatorfrisky]

let's see.. IIRC i've ruined 3 ring gears (taught myself how to set up R&P gears)

i think you'll get a BANG from the broken metal getting in between the R&P while driving. NOT because of a gap in the gear.

the 2nd time i destroyed a 12 bolt rear it banged 3 or 4 times before finally failing so hard that the ujoint at the T-case broke and caused me to catapault almost ass-over as i was pulling back into my driveway!!!

seems like a pretty easy check if ya ask me. pull the cover and let us know!

[chinweasle]

Originally Posted by senatorfrisky

let's see.. IIRC i've ruined 3 ring gears (taught myself how to set up R&P gears)

i think you'll get a BANG from the broken metal getting in between the R&P while driving. NOT because of a gap in the gear.

the 2nd time i destroyed a 12 bolt rear it banged 3 or 4 times before finally failing so hard that the ujoint at the T-case broke and caused me to catapault almost ass-over as i was pulling back into my driveway!!!

seems like a pretty easy check if ya ask me. pull the cover and let us know!

it'll be on the to do list. right now the truck is a big paper weight... I have to replace the lower intake manifold gasket.

[orangefj45]

there's a good possibility that you have a broken output shaft snap ring in the t-case. pretty common problem and something that's easy to fix.

drain the t-case. (make sure fluid looks good and is bright and red. any metallic particles are a bad sign)

remove the drive shaft.

remove the rear extension housing of the t-case. i believe it's held on with 3 14mm bolts.

take a look at the snap ring on the output shaft on top of the output bearing. if it's not there, then it should have fallen out in pieces when you pulled the extension housing.

get a new snap ring from the dealer, clean the sealing surfaces really well, apply some silicone and bolt everything back together after installing the new snap ring.

i like to let silicone set up overnight before i put fluid back in anything. less chance for leakage that way.

good luck. i hope this info helps.

if you get stuck/lost/confused/frustrated along the way, don't hesitate to ask questions and post some pics. cheaper than Fing stuff up.

[Juztyn00]

The cardon joint on the driveshaft on my 98 blazer mad a loud pop before it went. Are you sure the 4wd is even working? i had to put min up on stands front and rear to relize the axles locked in but it wasnt getting power...

[chinweasle]

Originally Posted by orangefj45

there's a good possibility that you have a broken output shaft snap ring in the t-case. pretty common problem and something that's easy to fix.

drain the t-case. (make sure fluid looks good and is bright and red. any metallic particles are a bad sign)

remove the drive shaft.

remove the rear extension housing of the t-case. i believe it's held on with 3 14mm bolts.

take a look at the snap ring on the output shaft on top of the output bearing. if it's not there, then it should have fallen out in pieces when you pulled the extension housing.

get a new snap ring from the dealer, clean the sealing surfaces really well, apply some silicone and bolt everything back together after installing the new snap ring.

i like to let silicone set up overnight before i put fluid back in anything. less chance for leakage that way.

good luck. i hope this info helps.

if you get stuck/lost/confused/frustrated along the way, don't hesitate to ask questions and post some pics. cheaper than Fing stuff up.

Thanks.. I'm hoping to get on this when we get back from vacation. We're finally at a point with our lot that I don't have to be out there every weekend clearing trees, so hopefully that means more time to spend on the truck.

[chinweasle]

Originally Posted by Juztyn00

The cardon joint on the driveshaft on my 98 blazer mad a loud pop before it went. Are you sure the 4wd is even working? i had to put min up on stands front and rear to relize the axles locked in but it wasnt getting power...

positive the 4wd is working. I did a quick visiual inspection of the joints and everything looked ok.... but like I said.. it was a quick inspection.