2000 bravada makes clunk from transfer case when going from drive to reverse

I'd look at the transfer case first.

most of the time a clunk from under the vehicle when shifting gears (whether going forward or reverse) is a u-joint. check them at both ends of the drive shaft. (possibly 1 in the middle, not familiar with your particular truck)

No. The transfer case takes Dexron/Mercon 3. What was installed instead, for fluid? If motor oil or gear oil was used instead. That would not cause a clunk. It would cause a loss of fuel economy. When vehicles get old and the mileage ads up. Parts loosen up and/or wear out. Clunking in the drive train could be related to the transfer case but could also be related to the drive shaft or the rear drive axle. Worn or bad splines, U-joints (rusted, loose, or seizing), worn ring and pinion is possibe too. If I can be more help just let me know. The more information and details that you can give, the better. Thank you.

Most suvs have the transfer case linked to the transmission. Best is to take both out at the same time.Generally:

1. Disconnect the battery
2. Unplug all wires from the transmission - transfer case unit. Make sure you mark them so you can reconnect them properly
3. Get inside the car and remove the shift lever(s)
4. Remove the starter
5. Remove the clutch slave if there's one or disconnect all cables from the unit
6. Support the car on stands so you can work easily under it.
7. Drain the oil from the unit may have 1 or 2 drain plugs
8. Remove the shafts making sure you marked the alignment where they are joined
9. Support both the engine and the transmission unit with the appropriate jacks
10. Unbolt the transmission from the engine
11. Remove the unit support (s)
12. Remove the unit from the car.

Important to remember the type of oil that goes in the trans and in the transfer case. They may not be the same. Also, some electrical transfer cases don't use any oil.

If this is the only problem you notice, it sounds like universal joint going bad in the drive line. Put the gear selector in Drive from neutral and then back to neutral and then select reverse. Listen for the clunk when changing from drive to neutral and neutral to reverse. A bad universal joint will make a clunking sound when the drive line reverses direction because of the slop in the joint due to the bad needle bearings.

bad transmission, it will need rebuilding or replacement. sorry....hopefully this helps

your problem is more than likely one of a few problems
there are two hoses on your transfer case one sucks in one blows out if one gets cloged it will go out completly so have it checked its starting.
or check the oil in the transfer case

It seems like no one else hear at FixYa is responding yet to both your requests about clunking in 4wd.
I see two requests....in the first a 2000 blazer from Gloeckz
there is a rapid clunking in 4wd!
In the second it clunks hard going in then won't drive!
This is rayenc11s' 98 Jimmy 4WD clunk I'm no trans specialist and not familiar with repairing or troubleshooting serious 4wd problems but it sounds like this may be a problem in the transfer case.

Since no one seems to be helping you but me I'd suggest you go to a transmission shop and ask them if this is a common problem that may lead to a bad transfer case if not corrected!

Make sure you have the proper fluid in your transmission case, transfer case and differential case first or have a quick oil change place check it for you!

Hope this is helpful.

Good Luck!
jackiaria

the vehicle has to be put on a hoist. turn the driveshaft that goes to the rear wheels,it is driven by a transfer case that is almost in the middle of the vehicle,just rearward of the transmission.
if the noise comes from the transfer case,then that is the problem.
the drive shafts for the rear have universal joints which can develop play and give the same clunk.
if it is the transfer case,it needs to have a gear replaced.
always warm up the vehicle for enough time for the engine to come down to 1000rpm before putting in drive,the fast idle is over 2000rpm,and puts alot of stress on the drive components,and over time wear them prematurely.

that noise could be a lot of things. a bad wheel bearing, a bad u-joint makes many different noises. bad bearings in the rear-end itself. the backing plates directly behind the wheels could be rotting out and crumbling. that is all wheel drive and takes a special fluid in the transfer case. if the correct fluid isn't used it will chatter bad. the special fluid is available from g.m. only and is called "autotrac-fluid".
you may need to have to have it professionally diagnosed to save from replacing a lot of parts that aren't going to fix it. Good Luck..........Scott