So today's trip was eventful.

All good pretty much the entire day. Not even a random suspension fault. Then as we were leaving I decided to take a stab at a muddy/rutted hill climb. Literally about 1/4 mile from pavement. I got maybe 50' up the hill and BANG followed by loss of drive and the engine reving high.

What the hell was that??? My first thought was I had killed my aftermarket rear driveshaft.

I rolled back down and put the truck in park to have a look under and noticed it kept rolling even in park. Hmmmm....

OK, if it's rolling in park that sounds like the parking pawl in the trans broke. In the old days it wasn't uncommon to hear about people jamming a transmission into park before coming to a complete stop and doing that. But you wouldn't break something like that doing a hill climb.

Well, maybe if the driveshaft was broken and decoupled from the rear and the transfer case clutch was open? But no, don't think so.

I found I could still drive on level ground forward and back, without any scary noises. So we dove the short distance to the pavement and aired up. I was hoping I could limp it on home, but heading toward highway 50 on the 2-lane it started slipping in gear - the engine would rev but no propulsion. Eventually I lost all drive. Switched to low range and was able to move again but still with slip. Not far later that stopped working as well.

So my buddy Nick towed me the few miles to Pollock Pines. While he was towing us we started getting some nasty noises and vibrations.

Then it was flatbed to home, where I've just unloaded her. At this point I'm almost certain it's the trans or transfer case, and my money is on the transmission. I haven't actually crawled under it at all to look other than to see that the rear U-joint is still intact, so there's diag work to do but you know it will be the trans - it's the most expensive part!

Actually, I'm not exactly sure how I'm going to verify transmission vs transfer case. It's not like I can verify output of the transmission separately from the T-case.

This is a new one for me - I can't think of anybody breaking either a trans or TC on an LR3. I'm sure somebody's done it, but not that I'm aware of.

 

Just crawled under the truck and found I might have a bit of luck - the driveshaft DID break, at the CV joint/transmission end.

My guess is because the TC can't be manually controlled the computer initially was sending some power to the front to let me move, but it overheated or something and the computer opened the clutch pack. And without the TC locked, the trans being in park didn't matter - the rear was free to roll since it was no longer connected and the front was open through the TC.

I've heard of people popping the CV on aftermarket driveshafts before, so when this first happened that was my initial thought, but I managed to get myself so worked up as things got worse (plus I had time on the tow home to let my imagination run wild)

So at least I've got a place to start. There could still be a problem with the TC or trans, but

 

Thinking about things more, I think I was able to drive out of the trail with the broken driveshaft because I was in rock crawl mode which is more aggressive on the lockers. Once on pavement I was in normal mode which was inclined to open the center diff. At least that's a theory anyway.

 

Wow....I actually have a spare (rear) driveshaft, but don't know that I'd ever be able to make that field repair. I'm not exactly handy with a wrench but figure if I really really had to, I could figure it out.

...but I don't know if I've ever actually packed it with me on a trail run.

 

I don't think OEM shafts generally suffer catastrophic failure. They do kill the center support over time, but that won't leave you stranded.

On my rig it's a bit of a PITA to change the driveshaft as you have to drop the skidplates first. But over-all it's not really a hard job. The bolts securing it are lock-tighted in place so they can be tough to break free but access is decent.

This was only the second outing on this generic driveshaft. Including street time, it had less than 1000 miles on it. I installed it and a generic front half shaft at the same time. The half shaft broke on the first trip and this on the second. Take this as a lesson - OEM costs more but it's worth it.

I actually had planned to rebuild my stock driveshaft and re-install it but needed a quick temporary fix before my last trip. Given the lack of flexing the shaft does on this set-up, I figured the generic would probably be fine until I got around to it. Guess not.

I didn't try to rush the center support so I haven't received it yet, but word is it will be here Wednesday. I'll try to get it installed next weekend and fingers crossed all will be well. I hope so - I have another snow run planned for the following weekend that I've been looking forward to for months.

 

was there a brand name of the company that made this wondrous drive shaft, so someone does not make the same mistake

 

You've had some epic/loud/sudden/disastrous failures Don! Just out of curiosity, what happened to your original driveshaft? Were you just going to rebuild a failed bearing?

 

That's crazy, for future reference if you put it in rock crawl is should have locked the center diff and your be okay (provided there weren't interference issues with broken shaft.)

I only know because someone stole my front shaft on disco and had to crawl under and lock it or she wasn't going to move at all.

That's crazy though. Wonder how my u joints are looking these days lol.

 

My story: I had recently had my rear diff replaced and decided I wanted to replace the locking motor as well. In the process of doing that, I thought I might as well put a new shaft in there since the old one was going to be out. Free labor. So that's how I wound up having a spare OE shaft that is perfectly fine.

 

I had figured out that I must have been able to move while on the trail because I was in Rock Crawl and it's more aggressive with the center locker. It still doesn't lock it full time though, so I had some slipping just not a lot and was able to move. When I got to the pavement and stopped to air up I also switched to standard mode which is why I only got about a mile down the road before it wasn't moving at all. I also wonder if I could have used my GAP tool to turn the locker on full time - I've never looked for that with it.

Last month before a sno-run on the Rubicon I was doing pre-flight and decided to inspect the driveshaft. That's when I found the center support was trashed. I figured there wasn't a lot of stress on it since there's little movement in a IRS rig like this. I also only had a couple days to swap it out before leaving. So I ordered a cheap aftermarket unit from BuyAutoParts.com for $355 instead of the $600 from LR. I then planned to order a new center support bearing from RoverWare (a friend here in the bay area) and swap it when I had the chance. He didn't have the part on-hand so I told him no rush (it's supposed to be here tomorrow actually).

I didn't just rebuild my stock drive shaft initially because of the time constraint and the fact it's not a straight-forward job...it's supposed to be a little finicky from what I've heard which is part of why LR considers the driveshaft non-servicable. Now I'm right back in the same boat as I only have a couple days at home to get the new support bearing in before we head out again next weekend. If it goes south on me, I'll fall back and run the RRC even though I haven't even started the build on it yet.