Front end grumble in 4WD ... what could it be?

[rover67]

Yeah the idea with a Double cardan shaft is the diff/pinion is pointed straight at the t case. Is that the case with your setup? In other words the diff flange should be square with the driveshaft.

Also that rear mount doesnt look too bad to me.

 

[Cruisertrash]

Yeah the idea with a Double cardan shaft is the diff/pinion is pointed straight at the t case. Is that the case with your setup? In other words the diff flange should be square with the driveshaft.

Also that rear mount doesnt look too bad to me.

I think k that’s my issue: the diff is not point at the t-case, which puts stress on the single u-joint.

I’m coming to the realization that I need to cut & turn the axle to get both the power muon flange and caster where they need to be. I guess for now I just learn how to replace a u-joint and keep feeding the front shaft u-joints.

 

[RDub]

It’ll be interesting to see how that u-joint looks if you do replace it. I don’t have a ton of bad u-joint experience but ones of mine that did fail started to chirp or clunk when going bad, not grumble. And the noises weren’t load dependent.

 

[Rzeppa]

Whenever I have had a worn u-joint, it will rumble and vibrate (but at least every time it has happened to me) when letting off the throttle, and will stop rumbling under load when applying throttle.

 

[RDub]

That’s why I’m curious, Jeff. Makes sense since needle bearings can rumble like crazy when they start to pit and fail. My u-joint issues likely just went too long before detection. Very interested in how this resolves, always good to learn stuff.

 

[Cruisertrash]

That’s why I’m curious, Jeff. Makes sense since needle bearings can rumble like crazy when they start to pit and fail. My u-joint issues likely just went too long before detection. Very interested in how this resolves, always good to learn stuff.

The interesting thing - to me anyway - is that theoretically this thing should have been rumbling and vibrating like crazy the whole time due to the pinion angle. It never did it until recently though. I wheeled it on the untouched driveshaft last summer and used 4WD last winter, had the DS rebuilt in the spring and then wheeler all summer. It wasn’t until a few weeks ago that it gave me any trouble.

 

[rover67]

do you have the original driveshaft? why'd you go double cardan? If you flip your shims for caster correction you'll get the pinion pointed back down closer to where it needs to be with a standard driveshaft and your caster woudl come back. Looks like they are ~6* shims? If so the pinion would end up around 1.5* so biased up maybe a few degrees from the t-case flange which is around what you want (to account for some axle wrap). Why'd you install them in that orientation? to try and point the pinion at the t case?

I have noticed that if the angles are a bit off, with a nice crispy new shaft/joints the vibs can be masked/not present since the shaft controlled tightly even though the shaft speeds are changing a lot with the misalighnment. once the u-joints loosen up a bit after some driving/wheeling you can get vibs when the shft is unloaded, like in between braking and throttle. A few shots of grease can get them quiet again sometimes. Usually noise/vibes only at higher shaft speeds like normal road speeds. Probably wouldn'f feel it on the trail unless it was super messed up. If the groan/vibes happen at slow speeds (walking, jogging) I would think it's not the driveshaft. If they happen at like 50mph (when light throttle coasting so the DS is not loaded with braking or accel), even higher then I'd suspect DS. I have also noticed that when not loaded but spinning like in 4wd and hubs unlocked even a improper setup can stay pretty quiet. Kinda have to coax a noise by feathering throttle when its all engaged if angles are slightly off and u joints are not crispy new..

 

[nakman]

I keep wondering if it has something to do with the shackle reversal. No real reason behind that, other than pushing my own unsubstantiated anti-shackle reversal agenda. I just keep wondering though.

 

[MonPetiteShoe]

The interesting thing - to me anyway - is that theoretically this thing should have been rumbling and vibrating like crazy the whole time due to the pinion angle. It never did it until recently though. I wheeled it on the untouched driveshaft last summer and used 4WD last winter, had the DS rebuilt in the spring and then wheeler all summer. It wasn’t until a few weeks ago that it gave me any trouble.

I think it's perfectly reasonable that you're detecting it now as opposed to last summer/winter.

The pinion angle could have produced the latent failure that you're diagnosing as the grumble. A few degrees between pinon and t case may have been enough to tear things up, but not at a catastrophic rate. (Read as: deteriorate faster than Rx maintenance intervals.) It sounds like you're on the right path adjusting the pinion angle and swapping out the u-joint.
I'm saying all this after just browsing through the thread. Take it with a grain of salt.

 

[Cruisertrash]

I keep wondering if it has something to do with the shackle reversal. No real reason behind that, other than pushing my own unsubstantiated anti-shackle reversal agenda. I just keep wondering though.

I KNEW you’d show up to say this!

 

[Cruisertrash]

do you have the original driveshaft? why'd you go double cardan? If you flip your shims for caster correction you'll get the pinion pointed back down closer to where it needs to be with a standard driveshaft and your caster woudl come back. Looks like they are ~6* shims? If so the pinion would end up around 1.5* so biased up maybe a few degrees from the t-case flange which is around what you want (to account for some axle wrap). Why'd you install them in that orientation? to try and point the pinion at the t case?

I have noticed that if the angles are a bit off, with a nice crispy new shaft/joints the vibs can be masked/not present since the shaft controlled tightly even though the shaft speeds are changing a lot with the misalighnment. once the u-joints loosen up a bit after some driving/wheeling you can get vibs when the shft is unloaded, like in between braking and throttle. A few shots of grease can get them quiet again sometimes. Usually noise/vibes only at higher shaft speeds like normal road speeds. Probably wouldn'f feel it on the trail unless it was super messed up. If the groan/vibes happen at slow speeds (walking, jogging) I would think it's not the driveshaft. If they happen at like 50mph (when light throttle coasting so the DS is not loaded with braking or accel), even higher then I'd suspect DS. I have also noticed that when not loaded but spinning like in 4wd and hubs unlocked even a improper setup can stay pretty quiet. Kinda have to coax a noise by feathering throttle when its all engaged if angles are slightly off and u joints are not crispy new..

The early 60s, mine is an 82, came with a double cardan driveshaft so I’m just running stock. The DC goes at the transfer case end. The noise happens immediately and at all speeds, even in 4lo when I’m moving slower than a walking pace.

Anyway, I took a vacation day at work today and hit a trail and now I have an even bigger concern - pretty bad transfer case sound in 4hi/4lo under load. Doesn’t do it when engine braking downhill, but flat or inclined ground … it sounds like it’s eating itself. Zero issue in 2WD. I have a spare t-case (and spare rebuilt transmission) so I’m going to get that dressed up and ready to swap in ASAP. @Crash was there and drove my truck for a bit. He can attest this is worse than driveshaft vibes.

Everybody say it with me now: “I LOVE LAND CRUISER OWNERSHIP!”

 

[Crash]

The early 60s, mine is an 82, came with a double cardan driveshaft so I’m just running stock. The DC goes at the transfer case end. The noise happens immediately and at all speeds, even in 4lo when I’m moving slower than a walking pace.

Anyway, I took a vacation day at work today and hit a trail and now I have an even bigger concern - pretty bad transfer case sound in 4hi/4lo under load. Doesn’t do it when engine braking downhill, but flat or inclined ground … it sounds like it’s eating itself. Zero issue in 2WD. I have a spare t-case (and spare rebuilt transmission) so I’m going to get that dressed up and ready to swap in ASAP. @Crash was there and drove my truck for a bit. He can attest this is worse than driveshaft vibes.

Everybody say it with me now: “I LOVE LAND CRUISER OWNERSHIP!”

Of course you do. Look where we went today, even with a hurting truck you made it out and back home again under its own power. Better than can be said for the newer built *eep that will probably make it home on a trailer with the blown steering box that we saw. Running a quart and a half low in the T-case probably didn’t do it any good your last time out.

 

[Rzeppa]

I said it before and this reinforces what I wrote - T-Case bearing

 

[rover67]

If you need guidance LMK, I've done a few split cases. Bummer it grew into a bigger issue but with your spare you should be set.

 

[Cruisertrash]

@Crash you’re right - as annoying as the transmission/t-case internal fluid leak is to monitor, I should have done a better job. @Rzeppa Seems highly likely.

 

[Cruisertrash]

If you need guidance LMK, I've done a few split cases. Bummer it grew into a bigger issue but with your spare you should be set.

I appreciate that and may be contacting you about that!

 

[Rzeppa]

@Crash you’re right - as annoying as the transmission/t-case internal fluid leak is to monitor, I should have done a better job. @Rzeppa Seems highly likely.

Your description of symptoms and observations has been concise and detailed.

 

[Cruisertrash]

Your description of symptoms and observations has been concise and detailed.

I try...

So many posts on Mud and this forum lack info and detail and the poster expects the answer laid at their feet based on a one sentence description. You can't figure out issues like this unless you're thorough in your thinking and testing.

 

[Cruisertrash]

Of course you do. Look where we went today, even with a hurting truck you made it out and back home again under its own power. Better than can be said for the newer built *eep that will probably make it home on a trailer with the blown steering box that we saw. Running a quart and a half low in the T-case probably didn’t do it any good your last time out.

Like I said yesterday, that Jeep couldn't have been more than a couple years old. There it sat, completely immobilized due to a busted steering gear box. Meanwhile my 42 gear box is hemorrhaging ATF and as long as I keep the pump reservoir topped up, it keeps doing what I ask of it. I obviously won't run it that way forever - I've acquired a spare core box for rebuild, just like I've been doing with lots of other parts like the transmission, t-case, motor, etc - but it'll keep running under less than ideal conditions.

Remember, I was born and raised in Toledo so I partially understand the "Jeep thing". So many people there drove a Jeep and I've seen so many issues. Aside from the 4.0L "high output" straight six motor being passable, the rest of the parts always have trouble.

 

[DaveInDenver]

Like I said yesterday, that Jeep couldn't have been more than a couple years old. There it sat, completely immobilized due to a busted steering gear box. Meanwhile my 42 gear box is hemorrhaging ATF and as long as I keep the pump reservoir topped up, it keeps doing what I ask of it. I obviously won't run it that way forever - I've acquired a spare core box for rebuild, just like I've been doing with lots of other parts like the transmission, t-case, motor, etc - but it'll keep running under less than ideal conditions.

Remember, I was born and raised in Toledo so I partially understand the "Jeep thing". So many people there drove a Jeep and I've seen so many issues. Aside from the 4.0L "high output" straight six motor being passable, the rest of the parts always have trouble.

I think this is more fairly an old vs new ethos. My truck decided to no longer start on a dirt track I drove up just west of Loveland the day I put on new tyres. I got to do a trail side wire harness troubleshooting and a fading daylight crash course on engine immobilizers. I was so pissed. Took me another 6 months to commit to selling the 1991 and I've been well punished by the Toyota gods for it.

ETA: Just read an interesting and not completely tangential article about Instant Brands bankruptcy filing. They make the Instant Pot (which I don't have, but I do have a similar decades old Crock Pot that I use nearly weekly) as well as CorningWare, Pyrex (also have, some I inherited from grandmothers) and other basic and durable kitchen stuff.

https://www.nytimes.com/2023/06/15/business/instant-brands-bankruptcy.html

The basic premise is this company made a product that was too good. It worked and never failed. So once they sold something it didn't need replacing and eventually they ran out of customers buying stuff.

Sound like a familiar path for a, oh I dunno, mid-90s auto company? If Toyota has kept building simple cars that all lasted a million miles by now all they'd be is a repair parts supplier instead of the world's largest new car manufacturer. Corporations in the current economy all have to continually grow or die. Planned obsolescence is the unspeakable word, even for Toyota.