juddering/vibration

[Alk-3]

Hey Everyone.
I'm having a bit of a vibration/juddering issue with my 67 88" sII.
I was driving in 4 wheel drive, and heard what sounded like a large stone flying off the tire and hitting the inside of the fender.I was going quite slow, so it struck me as odd that it made such a loud noise. Anyway, now I'm thinking it may have been something important flying off the engine or something.
Ever since the bang happened, I get some pretty sever judder, or vibration beetween 20mph and 40mpg. I think it's transmission related because if I step on the clutch it goes away. If the truck is in gear it is present, regardless of weather it's under load or not.
Also, occasionally when I try to pull out into traffic it will rev but won't speed up past about 20mph, I then have to pull over and try merging again, then it will all of the sudden respond normally.
Can anyone help me out with this? Does this sound like a tell tail sign of some known issue?
Again, this all happened suddenly after hearing a loud bang, which to me, rules out any part that may slowly wear out, like a u-joint or something

[LRMAN]

Sounds like a transfer case problem. Have you tried going from high to low and back again?

[pisten-bully]

Hmmm... not enough info to go on for me. Stepping on the clutch stops the noise and won't get up to speed sounds like a potential clutch issue. The "big bang" could be related... or not, best not to put too much emphasis on that intially. So, if it's a four-wheel drive problem only then, as LRMAN says, transfer case is suspect... but those other two symptoms don't really point to the TC. Keep trying/checking different scenarios: 4WD, 2WD, Hi, Lo, check your u-joints, check your axles, check your clutch linkage. Happy hunting!

[Alk-3]

just went for a test drive.
YES means there is definitely juddering going on, No means everything works as it should.

2wd hi ratio with unlocked hubs - yes
4wd hi ratio with unlocked hubs - yes
2wd hi ratio with locked hubs - yes
4wd hi ratio with locked hubs - no
2wd low ratio with unlocked hubs - yes
4wd low ratio with unlocked hubs - yes
2wd low ratio with locked hubs - yes
4wd low ratio with locked hubs - no

I think we're getting somewhere.

Also, the front U-joint seems a bit loose, I can move it side to side ever so slightly. I'm not convinced this is the problem though, as the juddering happened all of the sudden, not gradually.

[scott]

my guess, cuz it doesn't happen in 2 or 4wd, hi or lo, with hubs locked, that maybe when you unlock hubs the hubs aren't completely unocking. maybe there's a position between freewheeling and engaged that is making the shutter and interferring w/ power transfer from drive lines to wheels. so i would start w/hub inspections.

[pisten-bully]

Strange indeed, sort of inconsistent. And it doesn't explain why you are sometimes experiencing the inability to get up to speed.... I must admit I'm sort of stuck on clutch slippage with that one. Interesting thought on the lock-out hubs being problematic, but even with no front axle at all your rear wheels would get you up to speed. Maybe you've got a combination of things going on here? Hubs, u-joint, clutch? (Also, a u-joint can fail suddenly when it drops a needle or two because they'll either wear down gradually or fall out... and a bad u-joint could be causing your shuddering.) I'd try your sequence of tests again to see if you get the same results becaseu to me it looks sort of random?

[Alk-3]

basically it happens all the time except when the front hubs are locked.
I'll go have a look at the lockers now, and see what I can find...

regarding the U-joint; its not the U itself that's loose, it's actually at the slip joint where the driveshaft can telescope in and out according to vehicle hight etc.
what is that called? and what parts do i need to ask for?

[SafeAirOne]

I might lean toward the u-joints--check the front and rear. I know for a fact that they can occasionally bind up and bog you down if they are destroyed.

I'm not sure that the results of the test you performed would be an accurate indication of a U-joint failure, since it such a failure can have intermittent symptoms at low speeds.

Out of curiosity, how did you get it into 2-wheel drive low? If you have the ability to put it into 2-low, I would avoid using it--The front driveline can't take all that force by itself.

[SafeAirOne]

...Also, the splined slip joint you mention can cause vibration if it is worn--I drove around with my front driveshaft removed for a while and noticed a LOT LESS vibration and noise up front due to a somewhat worn slip joint.

[Alk-3]

Okay, I just went for another spin around the block. same deal as before, I tried locking one hub, and then the other. they both need to be locked to not have any vibration. one other thing I noticed, and this I think might be the cause;
As I came to a stop my foot hit the floor with very weak brakes. I crawled under the truck and low and behold, there is a leak in the pass. side rear brake line fitting.
The brakes and clutch share the same fluid reserviour don't they? Would it stand to reason the fluid has been pumped out and now the clutch is not working properly as well?
I'm waiting to hear back from the previous owner about what type of fluid he used. If I don't know what fluid was used previously, is there a safe option? Like maybe flushing the system and using dot5 or something? Is there such a thing as brake fluid that can be mixed with any other type?

[Alk-3]

I might lean toward the u-joints--check the front and rear. I know for a fact that they can occasionally bind up and bog you down if they are destroyed.

I'm not sure that the results of the test you performed would be an accurate indication of a U-joint failure, since it such a failure can have intermittent symptoms at low speeds.

Out of curiosity, how did you get it into 2-wheel drive low? If you have the ability to put it into 2-low, I would avoid using it--The front driveline can't take all that force by itself.

My mistake, I forgot that when in low it automatically goes into 4wd.

[pisten-bully]

If I don't know what fluid was used previously, is there a safe option? Like maybe flushing the system and using dot5 or something? Is there such a thing as brake fluid that can be mixed with any other type?
Whew! I'm confused! First, DOT 4 is good, I don't know anything about DOT 5. Shouldn't mix types, though, unless you're stranded somewhere of course.

So, pulling the front prop shaft is a great idea (SafeAirOne)! It'll help you to isolate the shudder... front axle and hubs, or transfer case... and hey, if the shudder is gone then you can maybe put your money on the prop shaft being the culprit.... (but don't bet too much because it could still be something else in the axle or TC.)

What about that problem you described that sounded like a slipping clutch? If you've got no clutch hydraulics then the clutch is full against the flywheel and won't do as you described (tough to shift, though!)

You're going to figure it out! Does sound like multiple issues from where I sit.

[Sputnicker]

How about a broken rear axle? It could account for the loud bang. If the two broken pieces are spinning against each other, you could easily get some shuddering. The shuddering would go away in four wheel drive because the front wheels are driving things and the two broken pieces are now turning at the same speed (no longer grinding against each other). It gets RPMs, but goes nowhere whenever the differential is trying to drive the broken axle.

Doesn't explain the hydraulic issue, but seems to address all the other symptoms.

[kevkon]

Would it stand to reason the fluid has been pumped out and now the clutch is not working properly as well?


Not really. The loss of hydraulic fluid to the clutch slave cylinder would only mean that you would not be able to fully disengage the clutch. I think you would know that the clutch is not fully disengaging when attempting to shift.
The symptoms you described, roughness at 20mph and up would usually indicate a out of balance wheel or other rotating drive train mass. But you also said it goes away when disengaging the clutch which might indicate a damaged pressure plate or disc.
You might want to check the motor mounts.

[Alk-3]

Okay, so here is an update:
I had a bad leak in the brakes, so I fixed that, and bled all 4 drums, and the clutch. That settled that, but the vibration was still there.
I had to do a long haul, (about 5 hours) with the truck loaded right down with very heavy stuff, and I was pulling a trailer, that was also loaded right down with machinery. The rover is a noisy ride to begin with, but it got noisier as time went on.
I got to my destination, and parked the truck for a few days, and then revisited the issue... It was far worst than before. I had to make a run into town to get some things, and was honestly afraid I wouldn't make it home.
On the way back home from town I drove by a guys house on the way who I met some time back and he said he had a couple of rovers he's working on. well, as luck would have it he was out in the drive working on his 109 (amazing truck in fantastic condition). I stopped to get his opinion on the issue, and he immediately said 'sounds like a u-joint'. I told him I had already checked and tripple checked them. Anyway, he crawled under it, and sure enough, the rear prop shafts front u-joint was on the brink of total destruction.
The only thing I can think of is that when I stop the truck I usually coast to an almost stop, then pull the parking brake to come to a complete stop, then I leave the truck in gear and get out. This practice may have bound up the prop shaft enough that it felt solid when I checked it earlier.
Anyway, my new friend happened to have an extra prop shaft in his parts shed that was in far better shape than mine, and I got home in one piece.
New parts are on the way from our hosts, so all is well in the end!:thumb-up: