Driveline thump/cunk when stopping/starting (2 Viewers)

[schum4]

OK I've searched a lot and found a good bit on the driveline thump, but I just want some reassurance from those that know. Ive owned my '97 for about 6 months now and it seems that the thump is getting a little worse. Just before I come to a stop I hear a couple (or few) clunks/thumps. If I'm careful with the brake I can make it stop without the thump, but then I will get it as soon as I let my foot off of the brake. A local Cruiser mechanic said that it wasen't harmeful and that a transfercase rebuild might meke it stop. I'm not sure if I want to go down that road if I don't have to but it sounds like the drivetrane is taking a beating.
Any thoughts on this would be greatly appreciated by this long time reader/first time writer.

ps. thanks Cdan for the parts and advice

 

[Rich]

Remove driveshafts. Apply grease directly to drive shaft splines / slip yokes. Reinstall. Repeat when the clunking comes back. What you are hearing is the result of the drive shafts binding up and then releasing when you stop and start. It is most likely not at all related to the transfer case.

Note that squirting grease in through the driveshaft zerk fittings is not an effective way to grease the splines. Once you dissassemble the drive shafts you will see why.

 

[schum4]

Thanks Rich, I know that this has been beaten to death, but I just wanted some reassurance that the driveline wasn't about to crap-out. I've tried the zerks, now I'll break it down.

 

[sjcruiser]

Note that squirting grease in through the driveshaft zerk fittings is not an effective way to grease the splines. Once you dissassemble the drive shafts you will see why.

This issue is isolated to only a few cases so please do NOT generalize for all applications!!!

Frank.

 

[alia176]

If you do separate the two halves of the driveshaft, be sure to mark them before hand! Let us know how things turn out please.

Ali

 

[Rich]

I am not generalizing here, but commenting on my observation of how the driveshaft is constructed.

I believe that in order for using the driveshaft zerks to be effective in greasing the splines that the driveshaft interior needs to be totally filled with grease. If you disassemble the driveshaft and examine the interior you will see why I believe this to be the case. I suppose it may be possible for centrifugal force to result in grease from a partially full driveshaft making its way to the splines, but I am not personally optimistic that this will happen. This is admittedly a presumption.

To the best of my recollection more than one person has shared personal experience of transfer case damage attributed to operating the vehicle with the driveshaft packed full of grease. For that reason I disassemble the shafts in order to grease the splines. I will not fill the driveshafts with grease.

If anyone is motivated to remove the driveshafts, please note that nuts that fasten the shafts to the flanges on the diffs are serrated lock nuts. So you need to turn the bolts, and not the nuts, in order to loosen. Turning the nuts while tight will wear down the serrations and reduce their locking ability.

You only need to unbolt the shafts at diffs in order to separate. The note to mark the shafts prior to removal is worth repeating. You want to have the two halves put back together exactly as they were prior to removal, I.E splines engaged exactly as before, in order to best preserve the factory balance job.

 

[schum4]

Thanks for the tips guys. I think that I will try to separate the shafts in a friends garage. It sounds like it would be easy to get sand in them if I tried it in my dirt driveway. -Damn south Ga sand.

 

[tarbe]

My FSM says to grease the slip yoke with the zerk....I took a chance today an shot a little (two pumps of the gun) in each zerk, watching carefully that I didn't expand the shaft.

After a couple mile spin, I went below decks and saw some grease had been flung out from the slip yoke, so is does not appear to be in hydraulic mode.

 

[semlin]

Robbie, do you leave any grease in the hole or do you just grease the splines?

I was just trying to cure this problem this weekend without dropping the shafts. I filled one shaft with grease then removed the zirc and drove around hoping to squeeze out excess grease while still getting something to the splines. Nothing came out despite some kurb hopping to try to flex it and it made no difference to the noise. It looks like there is about a 1/2 inch of slide in the shafts. There is a slight but annoying clunk whenever the throttle goes on or off and sometimes a further clunk when you stop. I am going to drop the shafts now.

 

[bdac]

I had experienced something very similar to this a while back and for the life of me I couldn't figure it out. Recently, I replaced the front diff, rear diff, transfer case and transmission fluids. I believe the clunk has now been resolved additionallly, humming noises which were emitted from the rear are resolved as well. Also, the fluid replacements sped up the delay time in locking/unlocking for my diffs as well.

The consistancy of the diff fluids were not bad- just viscous, thick and old, but not gloppy.

hope this helps.

 

[alia176]

In order to reduce my "thumping", I drove around a little bit w/o the zerks on both driveshafts. I saw no grease that was pushed out of the holes, much to my dismay. Unfortunately, my thump is still there. I'll separate the two halves to see the condition of the splines in the near future.

To my uneducated ears, the sound feels like a suspension settling thing. Coming to a stop, something is winding up and then releasing once you're moving. I'll check the conditions of the bushings and the tightness of all hardware up front.

Cheers,


Ali

 

[kenton]

Just to add smoke to the fire:
Now that I'm operating my '97 in 2WD mode, I've suddenly developed the 'clunk/thump' that schum4 describes.
When I go put my front shaft back on, I'll let you know if it goes away (if anyone cares).
It could be that there is a clue in here for someone's woes, I'm just not smart enough to figure it out yet.
(Other than the obvious 'Toyota can't make a reliable full-time 4WD driveline', but then I'd be the last person to make such a derogatory, over-generalized, and inflammatory statement such as that. )

Kenton

 

[IdahoDoug]

Kenton,

When your Toyota driveline fails to drive you to the mall or through the Rubicon, the word "unreliable" might be appropriate. But a small clunk on a vehicle you bought used and don't know how it was treated previously is something that falls short of that word.

DougM

 

[alia176]

Don't know why my reply didn't make it but could the thump be coming from the front radius arm mounting area?

 

[Rich]

The thumping is probably due to the drive shaft slip joints binding and then releasing due to insufficient lubrication. Every time you stop and start your suspension compresses / expands and your axle housings rotate in an arc, requiring the drive shaft to change in length.

 

[alia176]

Kenton doesn't have a front driveshaft! What's making his "thump"? I'm thinking his axle housing is rotating too much due to front radius arm bushing issues? Just a wild guess though!

 

[Rich]

Number of driveshafts does not affect my hypothesis. I expect both drive shafts want to change length when accelerating and when braking.

If I shift into nuetral before braking I never get the groan/thump/clunk whatever you want to call it noise when stopping or when starting afterwards. Greasing the splines and taking no other action eliminates the problem for a while. Thats my story, and I'm sticking to it!

 

[Rookie2]

Is it necessary to remove some of the grease that's packed in the end?

 

[nakman]

I wish this thread was stuck to the "driveshaft woes" thread, as each contain some valuable info about essentially the same topic. another reason to search first, and try to contribute to an existing post rather than just creating a new one. but I'm not here to preach mud etiquette, I'm trying to get rid of my clunk. What I've got sounds exactly what Ali described above in post #11. Have you figured this out yet?

also, I notice my rear driveshaft is installed with the splines near the transfer case, which I know is like everyone else's because everyone talks about how the grease from the splines gets flung out onto the muffler. But my front driveshaft has the splines towards the diff, not on the t-case side. So both shafts have the splines towards the front of the vehicle. can someone confirm that this is correct?

 

[landtank]

My splines on the front shaft are toward the T-Case as well. I know this from the large grease gob on the Tranny oil pan.