97 LC Downshift into first gear front end clunk? (1 Viewer)

[Fj80oregon]

Hey so I have been driving the cruiser quit a bit to break in the motor rebuild and am getting a front end clunk when downshifting into first gear via the kick down. If I manually shift through the gears no noises. It seems to only happen when I am trying to accelerate quickly and it down shifts. It pulls smooth after the initial clunk. Driveshafts have been recently rebuilt by a shop. Motor had 400 miles on fresh rebuild. All suspension is new and any bushing I could get to has been replaced. Any one come across this before or have any pointers??? Truck
Is 97 fzj80 with 260k Thanks in advance Wes

 

[Fj80oregon]

Bump

 

[LandLocked93]

Play in the t-case and/or front third could be suspect.
Has all that been sussed as well?

 

[Broski]

I would go over all Hardware in the front end and make sure they are torqued to spec. Especially the 4 big bolts the attached the control arms to the axle.

 

[gummycarbs]

am getting a front end clunk when downshifting into first gear via the kick down

Loose/bad motor or transmission mounts?

 

[Fj80oregon]

Loose/bad motor or transmission mounts?

All brand new with the motor rebuild. But will check torque. Thanks

 

[landtank]

Sticky throttle cable.

 

[landtank]

Sticky throttle cable.

Not sure why this got a laughing emoji. A sticky throttle cable will prevent the throttle closed switch to be actuated when your foot is lifted off the pedal resulting in a delay in the transmission to down shift.

 

[109madrid]

Grease the driveline, mine did the same until I refilled the driveshafts with grease

 

[mudgudgeon]

Check front drive flanges for play

 

[Broski]

It seems to only happen when I am trying to accelerate quickly and it down shifts. It pulls smooth after the initial clunk.

 

[Fj80oregon]

Not sure why this got a laughing emoji. A sticky throttle cable will prevent the throttle closed switch to be actuated when your foot is lifted off the pedal resulting in a delay in the transmission to down shift.

Throttle cable is brand new. But was thinking maybe to check the adjustments on all cables under hood. Thanks

 

[Fj80oregon]

Grease the driveline, mine did the same until I refilled the driveshafts with grease

Drivelines are freshly rebuild with new u joints and greased. But I will fill them this morning just in case the shop didn’t too them of.

 

[Fj80oregon]

Check front drive flanges for play

Check front drive flanges for play

How do I go about this? Or I can get the FSM out I guess!

 

[Broski]

You stated that you replaced the front bushing. and that it only happens under hard acceleration and a down shift to first.
Drive shaft, drive flanges would make the noise with just a small amount of throttle input.

 

[Broski]

To check the drive flanges have someone shift from forward to reverse while you look at the flanges for excessive movement. Pull the dust caps if necessary.

 

[Broski]

Have you checked the fore big bolt that attach the front control arms to the axle. If they are not torqued to spec they can allow the axle to rotate under hard acceleration and make the clunk that you describe. If left unchecked the movement can elongate the holes in the axle mounts. Ask me how I know !!

 

[Fj80oregon]

Have you checked the fore big bolt that attach the front control arms to the axle. If they are not torqued to spec they can allow the axle to rotate under hard acceleration and make the clunk that you describe. If left unchecked the movement can elongate the holes in the axle mounts. Ask me how I know !!

I have delta arms, I checked torque yesterday and all bolts/nuts are torqued to spec 127ft. Thanks for the help.

 

[Fj80oregon]

You stated that you replaced the front bushing. and that it only happens under hard acceleration and a down shift to first.
Drive shaft, drive flanges would make the noise with just a small amount of throttle input.

I’ll check torque on drive line hardware it’s not possible to get a torque wrench in there IIRC, I think I just tightened them with long box wrenches.

 

[mudgudgeon]

How do I go about this? Or I can get the FSM out I guess!

Jack one front wheel off the ground. Pop dust cap off the end of the hub.
Rotate the wheel back and forth and watch where the axle spline meets the drive flange spline..

A couple of degrees rotation is normal, if it's more than a few degrees, clunking in the drive line happens on acceleration/deceleration.