bw4405 "popping" noise

[spack]

Whats up guys? First post on here for me. Have been lurking/searching around on here for a few months now. Cant seem to find anything close to whats been going on with my t-case. Its a '98 xlt 4.0 ohv, 162,x.. mi. The truck has been in my family for a few years now and as far as i know its always had random/fantom 4wd noises and issues. When my brother first got it the 4hi-lo lights would flash their 6-pulse sequence, he had a shop look at it and they reported "no issues"... about a yr later, while my father was driving it, he started complaining about "popping" noises. I test drove it and we came to a conclusion it was cv axle wear. R2'd the cv's. Still popping but only under acceleration at about 3k rpm. About another year later i started driving it daily and messing with it more. Found if i unplugged the tccc/range motor harness the noise stopped but then the 4hi-lo lights begun to flash again. Fault noted that it was unplugged. No biggie. But now i had to climb under the truck to get 4wd again. Sucks if your stuck!! So, i did the BWM and also adjusted the range servo as the ford tsb mentioned. Now it does not pop under normal driving or acceleration BUT in 4hi AND lo off road if any load gets put on the front drive ie. soft sand, mud, or even a steep incline the t-case makes a loud popping noise rapidly and seems to slip id say atleast 50% power loss... it has not left me stranded yet. Key word, YET!! ANY help would be greatly appreciated! Im an avid wrench and have a pretty good understanding of the bw4405 operation and parts list, just have no hands-on on the guts.

 

[JK080]

Sounds like the chain inside the transfer case may be slipping over the sprocket teeth because the chain may be stretched. They can slip over the teeth and make a rapid popping noise.

I have seen chains in transfer case stretch so much they rub a hole in the bottom of the case from the inside.

 

[boominXplorer]

Check and see if you have a vacuum disconnect front axle, could be that not engaging also.

 

[spack]

Jk, of all the things i did not figure the chain! I was thinking the clutch or "ramp and ball" plate. I leave the "clutch switch" off unless i absolutly need 4wd. Guess i just need the time/money and just tear it apart... or just do the 5.0 swap iv been pondering

BoominX, its the '98 model so iv got the live front axle. Good thought tho! I had a gen1 blazer leave me stuck in the woods in florida for a few hrs... an awd expedition pulled me out... lmao!

 

[spack]

So i jacked the front end up and locked in 4lo... i can get about 1/3 wheel rotation from "lock to lock". ... positive gear mesh felt like about 1/8 rotation. So i agree its most likely chain strech. Im gonna replace the chain and whatever else need-be while installed still. Maybe do a little sticky on a "quicky rebuild" ... my only question, and im gonna split the case anyway to see what parts i need, BUT is there a way to know what chain i have? The 1" or 1-1/4"? Can i refrence a case number? Also, where would you recomend i order my parts? Iv just been on ebar for priceing but maybe somewhere else has better customer service?