1999 LC - Front drive train slippage? Loud grinding noise. Center diff lock controls it

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Ironman2011

Joined
Nov 2, 2016
Threads
3
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18
Location
KY
I originally posted about this on 11/20 but no replies were received. I have some new information.

I have verified that as long as the center differential lock (CDL) is engaged that the noise and engine revving doesn't occur. I believe something is slipping in the driver's side front wheel area. Here is what happened the other day: as described below, I was driving it again and the engine rpms shot up and was accompanied by a loud whirring noise in the front, I let off the gas and engaged the CDL and the revving/slipping was controlled, I could feel it start to slip and then I could feel the CDL sending power to the rear driveshaft and the engine wouldn't rev up and I was able to continue driving. This was repeatable. When I was almost home, I disengaged the CDL and a few moments latter, when I was coasting (foot off the accelerator pedal), the loud whirring noise started and then it changed somewhat to a skipping/grinding noise. I pulled into my garage and stopped with the CDL still disengaged and my foot off the accelerator pedal and on the brakes ... there was a slower (no revving) rotating grinding/skipping sound coming from the front driver's side wheel area. If I engage the CDL it stops.

I don't understand everything from the transmission to the wheels but it seems that something is slipping between the front driveshaft and the front driver's side wheel (not in the transmission). I haven't had time to take anything apart/inspect anything yet.

It seems that the front "half shaft" with the boots would be splined on each end and the only thing I can come up with is that the male or female spline is worn and allowing one to skip/rotate relative to the other (it seems this could cause a loud grinding noise like I'm hearing) but I've never heard of wearing out a spline drive. Having said that, I can't think of anything else that could cause this but as I mentioned I'm no expert.

Has anyone ever heard of either of these spline interfaces wearing to the point of slipping/skipping teeth? Any other ideas on what could cause a loud noise in the front, and could allow the rpm to rev up when the CDL is not engaged?

Thank you!
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Original Post:
Engine appears to rev up with light throttle, loud whirring noise in front
Discussion in '100-Series Cruisers' started by Ironman2011, Nov 20, 2016.
1999 Land Cruiser - no serious off-roading in its life but has 237k miles.

About 2 months ago I was driving at 75 mph or so on the highway and a loud noise seemed to come from the front left (driver side) and the tachometer shot up to ~ 4k rpm with no vehicle speed increase. I let off the throttle quickly and the rpm dropped (but my heart rate didn't) then reapplied the throttle easily and everything seemed normal since then. Today, the same thing happened several times while driving 30 to 50 mph. It sounds like a mechanical whirring sound that really gets your attention. Immediately after I let off the throttle and eased back into it today, I tried accelerating relatively hard and it didn't slip or whatever it is doing when it makes that noise. But then if a few minutes it would rev up under light load. I thought that since in a normal rear wheel drive car power is sent to the wheel with the least resistance and since the sound seemed to be coming from the front that if I engaged the center diff lock that the engine wouldn't rev up since half of the power would go to the rear wheels. I don't know if my logic is sound but it didn't do it again and I was able to get home. (I didn't want to engage the center diff lock since I was on clean drive pavement but I didn't want the engine revving up either and didn't want to limp home at 5 mph and back up traffic for miles so I tried it).

I haven't checked diff fluids or anything yet.

Our joke in the car was that it was an expensive sound :) :-( I'm scared.

Any ideas?

Thank you.

Ironman2011, Nov 28, 2016
 
Seems like you didn't use the search function.

But while I'm here, you should take a look at the front drive flanges that bolts to the hub.
 
Thank you ton504, Trunk Monkey, and jLB. I did try searching for a few words related to my problem before I originally posted but didn't seem to find something that sounded like what I had. After I reposted today I found "Solved! Slipping Drivetrain: Possible Causes? Order of Operations ?" which had some different symptoms but lead me to know the name of the drive flanges which I think is what you all are pointing me too. I apologize I didn't find it originally. I was looking up all sorts of stuff I promise ... just uneducated regarding the names of things other than higher level components. Regardless, I will pop the dust caps off and take a look. Thank you! I'll post my results when I get this figured out.
 
@Ironman2011 Definitely follow up with your findings for other guys that may come across your post when searching. Some pics of the failure would be nice.
 
To help you with future searches, if you go to the "more" search page you can search by the 100 series section and relevance, not by most recent. This usually helps me narrow stuff down.
 
Pop your center caps off of the wheels and use a screwdriver and hammer to remove the grease caps underneath. As TrunkMonkey stated above it sounds like a c-clip (snap ring per Toyota) came off of the end of one of the halfshafts on a front CV axle. This would allow the axle to pull inboard of the drive flange just enough to slip and make the awful grinding noise and slippage. Check it sooner rather than later before significant damage occurs to splines on either component.

If in fact the clip did pop off you can use a screw in the threaded hole in middle of axle to pull it out far enough to fasten a clip back in the groove machined near the end of the axle. Just make sure to replace it with a new c-clip as per Toyota FSM it is a "non reusable part". If you are in a bind and without a replacement at least use a pair of pliers and squeeze the original c-clip closed some to return a measure of tightness to it before replacing. If you don't it will remain sprung and loose enough to come off again under load.

I have attached a link that should direct you to a copy of the FSM chapter for 100 series suspensions. On page 16 there is a diagram of the parts referred to here that should help you visualize these components. http://www.dustbird.com/ih8mud/FSM/Suspension%20&%20Axle.pdf

Good luck and be sure to let us know what you find.
 
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OP, I know it's been a few years but was it just the C Clip? This morning on my way in to work I heard a faint pop noise from the front right of the truck as I was turning left – then no power and grinding noise. Hit the CDL and I was able to drive back home (less than a mile) no problem. I have a 2004 LC with 148k, original axles. I'm planning to drive it to my mechanic Monday to help diagnose but was wondering if this is somehting I can fix? Or if there's something I'm missing in my diagnosis so far. Thanks to this forum (and the search function) I already have a good idea of what happened. This cruiser has not seen any heavy off road duty. Thanks.
 
Thanks, will do. I crawled under and saw my passenger axel popped out and was loose - I could pull it out by hand about a half inch or so. I’ll check C Clip in the morning. Is there a chance axle is ok and it’s just needing a clip? I appreciate it.
 
Upon just seeing an email about the post from TXLX100 above, I realized that I never posted my results. In short, prior to the problem I posted about, I had paid a local repair shop (that had done some work for me before) to do some preventative maintenance and repack/replace the front wheel bearings at about 200k miles when they did the front brake pads. (I was feeling lazy and felt like I could afford it at the time … big mistake as you will learn below.) Well … when I popped the dust cap off, the c-clip was laying in a bunch of dry red powder and the half shaft was retracted. I pulled the half shaft out by utilizing the threaded hole in its center only to find that the splines on the outboard side of the groove where the c-clip sets into were completely "shaved" off. So the shaft would retract far enough inward under certain driving conditions that there were no male splines engaging the female splines of the drive flange and it would slip. That "red powder" was the iron from the steel splines that was just super fine rust particles and there was no grease to be found. I dumped the rust into a pile that was about a half inch tall in the center.

So, you might ask how did this happen??? Well, as it turned out, the local repair shop mechanic didn't bend the tabs down on the large washer when they did the bearing job and I could spin the large nuts off with my pinky finger. So the nuts backed off over time which put all the stress on the c-clip and over time the c-clip just kept cutting away at the outboard male splines until they were gone and the c-clip just slipped off the end of the now bare shaft.

I'm lucky the entire wheel didn't fall off as there was very little engagement of the outer nut when I got to it. Since everything was so loose I felt it necessary to replace the races and bearings as well. And of course I had to replace the CV half axle since the original one couldn't retain the c-clip.

Unfortunately for me and the family of the local repair shop, the owner died of a heart attack and the shop closed so I had no recourse.

So, the moral of the story is that I felt lazy and felt like I had some "extra" money … it ended up costing my a lot more and could have been catastrophic. Oh well. I learned a lot about the front end of my LC :-)

Things I learned:
- the air hammer tool described on this site for removing the cone washers on the drive flange works like a champ
- a flat pry bar that I have has a slot on the long end that the bolt that threads into the end of the half shaft fits through and it worked great for pulling the shaft out so you can measure the gap and fit the c-clips in. Others on here had some pullers with some brackets that they fabricated but I didn't and I was able to use the flat pry bar with an extra nut for spacing the bolt in the pry bar's slot with some wood blocks for adjusting the point of leverage and for protecting what I was prying against and have both hands free for measuring and installing.
- just order a few different thicknesses of c-clips, they are cheap
- setting the hubs in the sun and putting the bearing races in the freezer helped with installation of the races
- be careful when removing the races, you don't want to damage the inside of the hub with the end of the tool you are using to remove the races, I hit my once when my punch slipped, I was able to sand down the raised edge of the damage. The local repair shop had dinged the heck out of bore in the hub in a bunch of places when they did my bearing job … I repaired those spots as well.
- if you have to replace your half shaft, be careful not to push the new seal into the drive tube too far (can't remember the official name but it prevents the diff lube from leaking out around the half shaft). I put mine in the freezer and it went in too easily before I noticed how far it had gone. I removed it and had to buy a new one since I damaged it during removal.
- be very careful if you attempt to remove your ABS sensor as they are easily damaged because they just don't want to come out of the hole easily - my recommendation is to disconnect it from the connector up top, fish the wire down and out, and leave the sensor attached. If you do happen to damage it, I found a source on Alibaba in China that was about a tenth of the cost of the Toyota part and it has worked perfectly thus far.
- I set bearing preload as per the manual with a fish scale taking care to pull at a right angle. With new bearings and races, I did a lot of rotating in the direction of travel before taking each new measurement. I tapped things with a rubber mallet during rotation in an attempt to get things to be seated as best as I could. I set the preload force at the upper end.

Good luck,
Keith
 
Ironman2011 said:
- the air hammer tool described on this site for removing the cone washers on the drive flange works like a champ
Click to expand...
What tool is this?
- a flat pry bar that I have has a slot on the long end that the bolt that threads into the end of the half shaft fits through and it worked great for pulling the shaft out so you can measure the gap and fit the c-clips in.
Click to expand...
I did something similar, but had someone shift back and forth from D to R while I pulled (with the engine running). It popped right out after 2 shifts and very little effort on my part.
 
Search for drive flange and cone washers and I imagine you will find the post but essentially it uses a piece of hose on the end of a blunt air hammer tool. It makes the cone washers pop out easily (I didn't have a brass drift and there wasn't one in town for sale, but I had an air hammer and 4 attachments, one of the attachments was pointed and I used a cutoff wheel to cut the end off at the correct diameter to match the stud). The piece of hose just helps you stay centered on the stud during hammering.
 
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