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280GE Axle and T Case Troubles

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Teufel Hunden
Posts: 52

280GE Axle and T Case Troubles

Post#1 » Sun Mar 01, 2015 3:21 pm

I think have either a busted hub/CV/Axle Shaft and a T case issue. After drive a couple of hours on the highway (interstate) cruising around 75-80 mph, I got off the highway and when make a left turn at the stop light it felt like I was in 4wd with the front diff locked. Really wanted to push through the turn, I stopped at a near by parking lot to inspect for damage. I was in 2wd and the front diff lock wasn't engaged (doesn't work any way), shifted the t case from 2wd to AWD to 4HI to 4LO and it felt/shifted fine. Drove in very slow circles around the parking lot and front axle start making popping sounds and front of the 280 raised up with a louder pop and lowed down. After that the steering was normal but there was a very quite clicking/clunking sound coming from the front axle. When I drove around the parking lot I noticed that the speedo wasn't working, I know the speedo drive is in the t case so at a slow speed I turned to shift to AWD but it made a grinding sound. I stopped and shift into AWD, which felt normal/smooth and started to drive around again, this time the speedo was working. While driving slowly in the parking lot in AWD I shifted back to 2wd, which was normal other then the speedo dropping off line, but when I tried to shift back to AWD it made a grinding sound. I also noticed that the clicking/clunking sound was quieter in AWD then in 2wd, turning in circles didn't change anything. When I got the 280GE home I tried to drive up a clay hill to test the 4wd and in AWD/4HI/4LO the front wheels failed to turn. I jacked up the 280 and put it on jack stands and put it in 4hi and the drive front shaft turns but not the front wheels.

Right now I plan on pulling the axle down (hubs/knuckles) and inspect for damage. What could be the cause of the speedo not working in 2wd only? What would cause the t case grinding? It only grinds going from 2wd to AWD, going from AWD to 4HI is fine and when shifted to 4LO (when stopped) is fine.

There are no odd vibrations when driving (short dist.) got up to 50 mph.

Thanks for all advice and help.

Steven

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vadimivanovich
Posts: 8643

Re: 280GE Axle and T Case Troubles

Post#2 » Sun Mar 01, 2015 4:37 pm

That hurts.

I'm really sorry this happened - it's a pretty ugly situation. I hesitate to share my thoughts, but would hope for someone to do so if I was in your shoes.

You can NEVER drive any true 4x4 on dry pavement in circles. That's problem #1. Sounds like your front axle was locked when you drove in circles, until the lock teeth sheared off. That may have caused the TC problem as well.

You might be looking at an axle $haft, or diff lock part$. The TC sounds to have an internal failure - it should not be possible to disengage the speedo output, though Chris here would know specifics. This one may be best solved with a used TC. Don't take my word for it - check for yourself.

Still, it is quite strange to have the front diff lock engage by itself. Usually the failure mode is to never engage - its spring loaded to the open position.

This is what nightmares are made of! Keep us posted.

Edit: Thanks Chris - I knew you'd be able to sort it out. I didn't think of the CV :|

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Chris
Posts: 4549

Re: 280GE Axle and T Case Troubles

Post#3 » Sun Mar 01, 2015 7:42 pm

Speedo drive is running off the front output of the tcase (even though the speedo drive is actually in back of the tcase), so if front driveshaft does not spin, speedo will not work.

You say difflock is not functional, how do you know? FYI no difflock light means nothing, as the bulb may be out or the switch @the axle may be curroded or the wire to the switch could be damaged.

NEVER try to operate the difflock if it has not been regularly exercised recently, the difflock is operated with brake fluid, brake fluid is hydrophilic (attracts water) and brake fluid is lighter than water so any moisture in the air will accumulate in the difflock reservoir (through breather hole in cap) and this water will migrate to the bottom of the system, which is the master cylinder and slave cylinder. When water gets into the difflock system it rusts the "cylinder walls" of the difflock slave and master cylinders, but that rust is no match for the 2,000PSI+ of hydraulic pressure that is pushing on the slave piston.

So essentially what happens when rusty difflocks are activated is the piston moves one way (activated with hydro-pressure) but will never ever return under pressure from the small difflock return spring, leaving the difflock permanently on.

The clicking sound you speak of sounds allot like a broken CV joint.
CV joints break easily when they are extremely worn out, and they ONLY ware out when the G is driven on a loose front wheel bearing (misalignment of hub/CV/axle shaft/axle tube... These items must ALWAYS be in perfect alignment... if not:$$$$$$).

If one CV is broken, the front driveshaft will not spin while driving.

If your CV did break, it means the front axle has seen some severe neglect, and you will certainly need a new hub, new CV joint and likely a CV housing if the loose wheel bearing was driven on long enough to damage bearing seating surfaces in the CV housing.



DON'T EVER EVER EVER DRIVE ON LOOSE FRONT WHEEL BEARINGS!

Teufel Hunden
Posts: 52

Re: 280GE Axle and T Case Troubles

Post#4 » Mon Mar 02, 2015 5:17 am

Just to be clear, I didn't engage the front diff while driving. The problem with my front diff lock is a frozen slave cylinder, I have a new/used one but haven't installed it yet. The light on the dash does work because I pulled the slave cylinder off the front housing and manually triggered the light. The slide actuator inside the axle housing also moves freely but with a little force, when I removed the slave cylinder I notice that it was to the far right which I assume is "locked".

I checked the front wheel bearings in Sept and found the drivers side to be slightly loose, I pulled both sides apart and re-greased the bearings then tightened them up following the proper preload steps. Before I removed the front tires on Sat I checked for bearing play. Maybe the damage was already done prior to Sept. I've owned the 280GE for just over a year, so the PO was the source of neglect. I always try to follow factory service intervals and procedures, also as a Mechanic in the aviation industry I know the importance of proper vehicle maintenance/care.

I will be pulling the front apart this week to see how much damage has been done. I will report back with my findings but I fear the worse.

Chris/vadimivanovich thank you for your help and direction.

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vadimivanovich
Posts: 8643

Re: 280GE Axle and T Case Troubles

Post#5 » Mon Mar 02, 2015 7:49 am

I have good used CVs and some odds & ends for ya if you just want to get rolling on the cheap. You'd still need a boot, grease & clamps (any auto parts store).

I have a feeling you're going to need a bunch of bearings and seals too unless you've already gone through that axle. This is something pretty much all W460 owners have/will go through. Mike posted sources for all of the bearings and most of the seals needed for the job, but there are some unique bits that will be required from an official MB source.

I'm a former general aviation mechanic too, so I know you'll get it right!

Cheers,

Vadim

Loke
Posts: 100

Re: 280GE Axle and T Case Troubles

Post#6 » Mon Mar 02, 2015 8:14 am

Hi.

The CV brake in most cases, from your description you're most likely part of that higher percent, CV joints will finally brake from ordinary wear too..
Worn out king pin bearing or wrong king pin preload can also set the CV/axle out of alignment, as described.
Driving on pavement with 4x4 or with the diff lock engaged is a cardinal sin. :evil:
Please take pictures for posting when disassemling - it is always something to learn from them.
Good Luck with both repair and costs.

Loke

Teufel Hunden
Posts: 52

Re: 280GE Axle and T Case Troubles

Post#7 » Mon Mar 02, 2015 10:43 am

Loke,

Driving on pavement with 4x4 or with the diff lock engaged is a cardinal sin.
I was not driving in 4wd on the pavement, I think some of you have misread what happened or I didn't properly explain it. The only time I put it in 4wd was while sitting stationary, the front diff lock wasn't physical engaged from inside the cab either. I did how drive in a few circles in the parking lot at a very slow speed, less then a couple mph (idling speed) with door open to listen for anything.

I really appreciate everyone's help. I will take pics of the damage I find. I am going to throw this disclaimer out there now, if the damage is is going to cost me more then $1k (basically more then a axle rebuild kit) I will be swapping in NON-Mercedes axles. I have found a good deal on a set of Toyota Land Cruiser FZJ80 axles with lockers, the LC front axle is passenger side drop with a high pinion. There is a lot more cheaper options for gearing and stronger components for the LC axles. I have already decided on how to handle the suspension set up with new axles, ORI Struts are made a short distance from me and I would try to talk them into testing a tuned setup that is geared towards the G Wagon. I know this is going to offend several of the die hard Mercedes purist here.

ORI http://oristruts.com/

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vadimivanovich
Posts: 8643

Re: 280GE Axle and T Case Troubles

Post#8 » Mon Mar 02, 2015 11:16 am

No offense, go for it! One fly in the ointment though: the front axle spins the wrong way :?

You'd have to swap a transfer case too, which might only compound your problem.

Maybe put a G body on the LC?

Teufel Hunden
Posts: 52

Re: 280GE Axle and T Case Troubles

Post#9 » Mon Mar 02, 2015 11:55 am

Good point, so the G wagon front diff is reverse rotation or is it the T Case? The Toyota Land Cruiser front ring and pinion is reverse cut.

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vadimivanovich
Posts: 8643

Re: 280GE Axle and T Case Troubles

Post#10 » Mon Mar 02, 2015 12:39 pm

Well, both the front R&P and subsequently the TC are reverse rotation. Stinks for custom guys like you...

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