WTHeck - klunk!

[WannaBe68]

Has anyone ever found the problem of the mysterious KLUNK to be in any one of the input / output / adapter with the arrows in this picture - or a combination?
Tap the gas peddle on and off and the KLUNK from hell is still happening. All U joints are new, Transmission has fluid, tie rods/ends are tight, motor mounts are a year old... BTW - not my picture - I pulled it from another thread.
Thanks in advance!

[kwmech]

Pretty common, the splines get worn out and have quite a bit of slop in them. Take a close look and you will see it along with the coupler inside the adapter. The 4 speeds are the worse for it.

[WannaBe68]

Okay thanks...
I should have mentioned it's a stock th350 4x4 auto trans/adapter/np205

Thanks again!

[Richard]

As kwmech stated there could be slop the coupler sleeve. I damaged a few in my k20 when I had the manual (10 spline) and after I swapped to a th350. Though take note that the 205 is an old gear driven box. While it is strong it is not built with tight tolerances or for quiet operation.

[WannaBe68]

Thanks...I'll have that looked at!

[sweetk30]

the idler gear bearings are set with shims . if they get sloppy they can BANG back and forth in the case under power and off power like you have said .

you might be able to pull a fill plug or drain plug and see if you can push the idler gear in the case . if you can it needs to be checked out for bad bearings or re shimmed .

[57taskforce]

Originally Posted by Richard

As kwmech stated there could be slop the coupler sleeve. I damaged a few in my k20 when I had the manual (10 spline) and after I swapped to a th350. Though take note that the 205 is an old gear driven box. While it is strong it is not built with tight tolerances or for quiet operation.

All of the advice in this thread is good feedback, I agree with Richard. The 205 in all reality is only going to be so quiet. It was designed to be as strong as a mule and as tough as a rhino. Unfortunately one compromise in those to attributes is a little noise. I was pretty lucky when I tore mine down and my coupler and the output and input splines from the tranny and the transfer case weren’t in bad shape. I’ve seen some that were pretty bad in the past. My idler bearings were pretty wore out though so I did have the idler slop sweetK30 mentioned. Pretty amazing that plenty of these things are approaching 50 years old and have never been rebuilt. All I replaced in mine was bearings and seals, no hard parts were replaced at all.

[jeffahart]

"KLUNK from hell" do you have a Detroit Locker"


j

[1976gmc20]

I don't remember my 73 or 80 or 71 being noisy in the T/C. Of course they were all new or relatively new back then. I think the 71 got up to 90K-something when we sold it to buy our first Suburban (2wd). The 73 was in the 70-80K range when I traded it for the 80, but I sold the 80 at about 22K.

[WannaBe68]

Originally Posted by jeffahart

"KLUNK from hell" do you have a Detroit Locker"


j

No Detroit Locker... Everything is original.
Seems the consensus is pointing to the 27 spline adapter coupler... That's what I'm going to have someone take a look at first chance I get.
Thanks!

[Yukon Jack]

Some trucks came with the No-Spin from the factory - it is the same as a Detroit Locker. Check you SPID just to be sure. They can be very klunky.

[jeffahart]

Originally Posted by WannaBe68

No Detroit Locker... Everything is original.

This is an original No Spin(Detroit locker) in an Eaton. Just saying, you might want to be sure where slop is originating. So you may have one as original.

Originally Posted by WannaBe68

Seems the consensus is pointing to the 27 spline adapter coupler...

I dissent until rear end is for sure. But if you are for sure then pull transfer. Doesn't hurt to pull anyway, but if your paying it might hurt a bit.


j

[jeffahart]

Originally Posted by Yukon Jack

Some trucks came with the No-Spin from the factory - it is the same as a Detroit Locker. Check you SPID just to be sure. They can be very klunky.

You beat me to it. I need to learn to type faster!

j

[Richard]

Before tearing into the t-case maybe drop the driveshaft and check the yokes on both the t-case and rear end.

[WannaBe68]

Ha...okay - thanks fellas'.
I had the rear axle rebuilt not too long ago...new bearings, one shaft and new gearing put in. But thinking about it, I honestly can't say whether or not the yoke was replaced! So I'll drop the driveshaft and have a look. If nothing appears wrong back there then it's on to the Adapter coupler...
Thanks again!

[Richard]

Did not mean the actual yokes. Rotate the yokes back and forth to check slop in the t-case/adapter and diff.

[special-K]

I ordered a '92 K3500 6.5TD/NV4500 pickup. When I went to pick it up I drove it around the lot with the salesman riding along. It clunked (more like clank) when on and off the throttle and I mentioned that. He said "That's normal". I accepted that as typical for what a salesman will say, and I'll watch it under warranty and see how it goes. I drove that truck for 22 years, of work, and 335k miles and never changed a u-joint.

Take any truck, jack rear wheels up, grab a tire, and move forward and back. What happens? There is slop and you hear it

[Richard]

Originally Posted by special-K

I ordered a '92 K3500 6.5TD/NV4500 pickup. When I went to pick it up I drove it around the lot with the salesman riding along. It clunked (more like clank) when on and off the throttle and I mentioned that. He said "That's normal". I accepted that as typical for what a salesman will say, and I'll watch it under warranty and see how it goes. I drove that truck for 22 years, of work, and 335k miles and never changed a u-joint.

Take any truck, jack rear wheels up, grab a tire, and move forward and back. What happens? There is slop and you hear it

100% agree. But with rear end being worked on it would not hurt to check for excessive movement.

[WannaBe68]

Notes taken, Fellas' - appreciate it!
I'll have some time this weekend to have a look...