What are the signs of a failing 80 series transfer case? (1 Viewer)

[chbrow10]

I've got a 96, US spec 80 with about 379,500 miles on the transfer case. I definitely have a clanging in the t-case when going from forward to reverse. I'm trying to understand how to know when it needs a new t-case or a rebuilt. Noises? pops out of gear? What is typical in these trucks when the t-case goes bad?

 

[LandLocked93]

A video of what you're seeing/hearing would help alot.
Apart from a failing VC (viscous coupler) which OTRAMM says hes never seen happen it's probably just wear and clearance. These are not chain-drive units.
It can be rebuilt. Which is usually when alot of folk running larger tires will regear it and swat 2 flies with one chopstick.
Otherwise, unless you know what parts are going into a rebuilt unit you're looking to buy, DIY is a better option IMO.
Ensure it is full of fluid and if not, fill it and re-eval befor getting into a rebuild or buying rebuilt.

 

[robnicko]

try taking one of the driveshafts out, engage CDL and drive as 2wd. This will help identify if the clanging is the TCase or general play / slop in other areas of the driveline (Ujoints, slip joints, CV's, drive flanges etc)

 

[greentruck]

I've got a 96, US spec 80 with about 379,500 miles on the transfer case. I definitely have a clanging in the t-case when going from forward to reverse. I'm trying to understand how to know when it needs a new t-case or a rebuilt. Noises? pops out of gear? What is typical in these trucks when the t-case goes bad?

Over the years, it turns out that most "Is my T-case going bad?" questions turn out to not be the transfer case. Usually some othere driveline issue, but the T-case is usually notably bad only when cracked open and oil is running out.

 

[Truck Enthusiast2]

It sounds like the clanging you're experiencing when shifting from forward to reverse might not necessarily indicate a failing transfer case right away. The noises could stem from wear and clearance issues, and a video would indeed be helpful to diagnose the specific problem. Also, consider checking for any potential play or slop in U-joints, slip joints, CV joints, and drive flanges in the driveline. Before deciding on a new transfer case or a rebuild, ensure your current one is adequately filled with fluid and evaluate any fluid leaks. Remember, transfer case issues might not always be the primary cause, and it's wise to rule out other driveline factors.

 

[jonheld]

An 80 Series transfer case is almost bulletproof. You would have to try pretty hard to have one fail. As long as there is gear oil in it, look elsewhere for your issue.

 

[OffRoadScott]

That banging could be bad u joints with a ton of play in them.

 

[chbrow10]

I’ve checked all the u-joints and they all look good to me. The t-case fluid has been drained and refilled with new within the last 5000 miles. No signs of fluid leaking.

I can put my hand on the t-case while the trans is shifted from forward to reverse and the “clanging” is definitely coming from within the t-case. I’m not concerned with that noise, as I think that is normal for the miles on the car. I have other noises that I am trying to tell if these are t-case noises or just 27 year old car noises. The noises will likely not be caught on video due to all the other noises….

 

[veiloctane]

a wineing noise from bearings i believe is the start! but there easy to rebuild

 

[Kernal]

@chbrow10 : What weight/type of gear oil are you using in the transfer case? A heavier weight might quiet things down if the noise is coming from inside the case. Everything else has already been said above.