NP 231 wear and tear

The transfer case in my '94 (160,000 miles) is starting to sound a little bit sloppy when in 4H. Is there an automatic chain tensioner in the NP231, or is it manual (or is there any at all??)?

I never drive with it in 4-Hi on dry or just wet pavement, but I do use it quite a bit on snowy roads. Do these wear out around this kind of mileage, or should I be looking for something more specific?

Thanks -

Andy

It might just be that your chain is stretching and needs replacement...i would open it up and see what kind of material is also on the magnet.

pete

I was assuming it was chain stretch, but I wanted to know if there was a tensioner on the chain, or if it's just "in there", kinda like in a timing chain gearset.

When you say "open it up", do you mean just pull the plugs and take a peek indide, or pull the TC out and split it? If I'm peeking inside, what am I looking for?

Thx -

i dont think you will be able to see much by pulling the plugs. the chain is "just in there" btw. you can split the case and leave the back half attached to the tranny. it a pretty easy job and shouldnt take very long. you will need a 10 mm (if i remember right)) twelve point socket for the top bolt, and a good pair of lockring pliers. the ones with a flat tip not the pointed ones.

AndyS said:

I was assuming it was chain stretch, but I wanted to know if there was a tensioner on the chain, or if it's just "in there", kinda like in a timing chain gearset.

When you say "open it up", do you mean just pull the plugs and take a peek indide, or pull the TC out and split it? If I'm peeking inside, what am I looking for?

Thx -

Click to expand...

No chain tensioner BTW. Sounds like tome for a new Chain.

Hmmm....didn't realize you could just pull the back half of the TC case off with it still mounted to the tranny. That might be an option for me once the weather gets a bit warmer and there's no ice in the driveway.

What am I looking for? What is considered an acceptable amount of slack in the chain? Will a stretched out chain slap against the case body? And, can the chain be replaced easily with just the back half of the case off? Are bearings/seals ever an issue with the NP231? Just looking for clues - thanks again for your replies.

Andy

the chain can slap if its too loose and it is easily replaced. bearing and seals are not an issue unless they were before you tear into it. You will know from the fluid leaks and or excessive play in the yoke. you will need to remove both yokes though, an air impact wrench is good for that job. its a lot easier and less time consuming to just split the case while it is still attached. should take 2 hrs or less hours to disassemble and reassemble.
if i remember right you need to put it in 4 low before you pull the shaft (someone will correct me if i'm wrong)
remove both yokes
pull the speedo cable (not sure if a 94 has that or a sensor)
pull the vaccum lines
remove output shaft tail cone
remove the two lock rings on both sides of the speedo gear
pull speedo gear
pull the pump ( when reinstalling make sure the pump line is attached )
then split the case.
(the magnet will be in a little slot at the bottom of the case)
there should be write up somewhere in here