Good wat to test transfer case?

[80cruiserscool]

needing some help in finding out if my transfer case is causing the whinning noise I am getting from underneath my 96 with 135,000 miles on it. I am not sure what steps to make in order to see if it is the drive shafts, or the transfer case. I get the noise when i am accelerating the truck, it subsides when i let off the gas. the noise is more of a growl than a whine but its not the driveshaft growl that i got from lifting originally!. if you will tell me how to test or what to look for in the transfer case I would appreciate it!
thanks
Steve

 

[brent]

80cruiserscool---

Does the whine correlate with RPM's, I have a whine that hits right around 1,700 up to 2,000 but actually gets better as the vehicle warms.......or I get use to it??? Anyway I did a little research and am thinking mine is front diff related, could this be the case for you??? Sorry not more help, I will try to figure out where I found the info.........

 

[elmariachi]

I get the noise when i am accelerating the truck, it subsides when i let off the gas. the noise is more of a growl than a whine but its not the driveshaft growl that i got from lifting originally!. if you will tell me how to test or what to look for in the transfer case I would appreciate it!
thanks
Steve

Can you feel it if you hold onto the shift lever?

Jim

 

[80cruiserscool]

no there is no vibration in the shifter. I do experience it more in the higher rpm's especially on the interstate! not sure if i am going to have to remove the shafts to see if one of them is doing this or if it is the transfer case?

 

[Hltoppr]

Get it on a lift or jack stands (good ones!) and run it up to speed.

-H-

 

[80cruiserscool]

thanks that is a good idea it would take all of the road noise out!

 

[Hltoppr]

Make sure the center diff is locked.....

-H-

 

[80cruiserscool]

call me ignorant but why would i need to lock the center diff for this test?

 

[Hltoppr]

If you haven't added the center diff lock button, the truck will have to be in low range for the center to lock. When you put it in 4 low, look for the diff lock light on the dash. You may still be able to figure out if your noise is diff or t-case related even being in 4 low.

-H-

 

[Hltoppr]

Just reread your question... Without the center diff locked, the engine power will try to reach the area with the least resistance. If all four wheels are in the air, you will not be getting a 50/50 split of power to the front and rear. Likely result, your front end will not turn very much, if at all.

-H-

 

[80cruiserscool]

got ya thanks

 

[semlin]

an intermittent whiny drivetrain noise under acceleration or at highway speeds seems to be common on these trucks and is probably nothing to worry about.

before getting into sherlock holmes mode I would suggest that you eliminate the easy to fix maintenance possibilities and lube the spider/u-joints, drop the drive shafts, clean out and lube the drive shaft yokes, service all your wheel bearings and change out the t case oil and diff oil front and rear.

If none of that works, I am not sure if running the truck on a lift or stands would allow you to similuate driving speeds unless you have four wheel dyno rollers as well. Even if it works, I wonder whether it would simulate the load conditions that generates the whiny noise.

I think the best way to isolate it is to get a CDL switch then take two test drives, each with one drive shaft removed. If the sound does not go away on either test drive then the problem is a wheel bearing, the t-case or the tranny.

 

[80cruiserscool]

I did change the tcase fluid two nights ago it was definitely in need of a change. i think it helped a little but this noise is still prevelant. it seems to be there more after it warms up and all the fluids are moving easily. i will try the driveshaft removal this weekend to see if its one of them. i need to pull the rear one anyway to clean it out! i have a new double cardan up front from slee i hope it wouldn't have a problem yet? but i will drop it if the rear doesnt turn out to be the problem!
thanks

 

[robbie]

Any leaks from the outputs of the T-cases if so, you may need to replace the sealed bearing and the seal. You will need the FSM to do this. If both it is easier to pull the T-case out to do both. The sealed bearing has grease and over time this grease leaves the bearing and they can get dry(yes even in a oil bath enviro) this can create wear in a certain pattern, so when lifting a truck you now put stress on a different part of the bearing, so maybe creating sound that you did not have. later robbie

 

[80cruiserscool]

how hard of a job is it to do the seals and bearings?
i do have the fsm and have looked at it. doesnt appear to be to difficult , are there any secrets that help to know?
grooms