Driveline / Transfer Case Concerns (1 Viewer)

[DIGLERZ]

Help - Looking for input from the experts before I yank the T/C..

Background - I've been chasing a "loose" feeling in the driveline of my 1994 LC for months, at this point I'm wondering if it's more Transfer Case related then anything else.. When vehicle is moving about 10-15mph on flat ground with no real load on the driveline if you wrap throttle lightly you get a "very slight" feeling/sensation like the driveline is lunging but the car is not..

Transfer case has been rebuilt with low range gears and part time kit, In my search for the cure thus far I've replaced all driveline bushings both front and rear and pulled the rear driveshaft and had it inspected.

Yesterday while continuing to try and track down the cause I focused on the T/C and low high range shifter, this may sound crazy but it almost feels like the gear set inside the T/C is shifting slightly forward/back inside the T/C as throttle is pressed/released in a no load situation.. It's also seems to be more noticeable when the transmission has shifted into 2nd rather than 1st as you cruse across flat ground..

I'm wondering if it might be a shim issue in the T/C but wanted to get some input before pulling everything apart..

Thoughts, input, suggestions appreciated..

Thanks, Chris

 

[-Spike-]

Help

Could be nothing, but by your join date and sig line I'm assuming you're not new to 80's and you're actually feeling something out of the ordinary.

Did this feeling start after the t-case rebuild? If so, you might have a problem, or you might be simply paying more attention to the driveline feel (AKA 'obsessing', something quite common in this community). If it was there before the t-case rebuild, it's likely not the t-case. Of course, that depends on your definition of 'rebuild'.

I'd be looking at the diffs. The gears meshing in the t-case are pretty straightforward, but the ring and pinion interface is finicky. If there's excessive lash in either diff it might manifest as a loose feeling. It's unlikely that both diffs have an issue, so maybe pull both driveshafts and see how much rotational and lateral play there is at the pinion flanges. If one has significantly more than the other I'd be looking into that.

FWIW I'm just spitballing, all purely conjecture based on a description of an issue I've never felt myself.

 

[Malleus]

You mentioned "driveline bushings"? Exactly which "bushings"?

I'd start with the obvious - U-joints - and move outward from there.

 

[DIGLERZ]

Appreciate the input..

I had Zuk set up gears F/R about 18 months ago.. Rebuilt both axles with new shafts gears etc at that time.. Didn’t notice anything out of ordinary afterwards..

Pulled transfer case for low range gears and PT kit about 12 months ago.. Didn’t notice anything immediately but shortly afterwards I started to feel/notice the loose sensation as described..

While working on some suspension updates over the last few months I noticed some suspect bushings and thought “ahh” that’s my problem. Having replaced all suspension bushings at this point I’m still encountering the concern..

That’s primarily why I’m questioning the T/C at this point as the most likely source of the issue..

 

[DIGLERZ]

Hi,

Replaced all upper/lower rear trailing arm bushings and all front radius arm bushings.. Pulled rear drive shaft and had shop check u-joints and balance to confirm everything was good...

 

[BILT4ME]

Did all the cross members get tightened back up, or any broken motor mounts or transmission mounts?

 

[DIGLERZ]

Cross member is tight, I’ll certainly look further into mounts..

Stopped with brakes applied, throttle input doesn’t seem to indicate any movement/twisting of motor that would indicate mount issues..