1997 4runner rear differential clunk

Hello, I brought my 4runner in to fix a rear axle seal and to see if they could isolate a clunking noise I've been having. They said the clunking was coming from the rear differential (I believe him as that's what I heard, while driving or even just putting it into gear). They have yet to call me back, but any guesses here as to whether it is a bearing (my guess, as it is most pronounced on a bumpy road) or a cracked gear or something else. I've been driving with a clunk for about a week, but have various clunk problems for the last 80k miles (I have another thread here on that issue).

It has 240k miles. Could be a $1000 repair bill. I've never used this mechanic before so don't know for sure how honest he will be with me. All thoughts appreciated. tia!

Just talked to the mechanic, the differential bearings are going bad. $800. The inner seal on the left side is starting to leak also. I decided to just replace the inner seals on both axles and put it back together for $200-250. Otherwise would be spending $1000 or more to do it right, and with 240k miles, I think it might be time for a new car.

Hello, I brought my 4runner in to fix a rear axle seal and to see if they could isolate a clunking noise I've been having. They said the clunking was coming from the rear differential (I believe him as that's what I heard, while driving or even just putting it into gear). They have yet to call me back, but any guesses here as to whether it is a bearing (my guess, as it is most pronounced on a bumpy road) or a cracked gear or something else. I've been driving with a clunk for about a week, but have various clunk problems for the last 80k miles (I have another thread here on that issue).

It has 240k miles. Could be a $1000 repair bill. I've never used this mechanic before so don't know for sure how honest he will be with me. All thoughts appreciated. tia!

Have you tried greasing the sliding joint in the drive shaft. Without sufficient moly grease it can stick and cause this type of noise. All it requires is some grease. This is a very common problem.

Thx for the reply. I'm aware of that problem, though it has been a while since I greased it so I just did it now. Thank you for the reminder.

The clunk is now almost 100% gone. But I'm puzzled as to why. The mechanic said replacing the gear oil might help with the noise a bit, but I wasn't expecting it to go away. He is now on vacation for a week so I can't follow up with him right now. All that was replaced were the inner seals.

Does anyone have a thought on why the noise is mostly gone and, more importantly, which bearing in the differential is going bad (assuming it's a bearing, I know nothing about differentials).

And the reason I ask, I'm not sure if I should fix it or sell it. Would love to keep it but it does have 240k miles on it and don't think a $800 bill is going to be money well spent. tia.

Thx for the reply. I'm aware of that problem, though it has been a while since I greased it so I just did it now. Thank you for the reminder.

The clunk is now almost 100% gone. But I'm puzzled as to why. The mechanic said replacing the gear oil might help with the noise a bit, but I wasn't expecting it to go away. He is now on vacation for a week so I can't follow up with him right now. All that was replaced were the inner seals.

Does anyone have a thought on why the noise is mostly gone and, more importantly, which bearing in the differential is going bad (assuming it's a bearing, I know nothing about differentials).

And the reason I ask, I'm not sure if I should fix it or sell it. Would love to keep it but it does have 240k miles on it and don't think a $800 bill is going to be money well spent. tia.

What makes you think the clunk wasn't caused by the dry splines?

Thx for the reply. I hadn't thought of that. There is no bearing noise, grinding or howling. The mechanic said there was a slight resistance when he put torque on the axle shaft, then it would kinda bust loose and spin freely. He thought it was a bearing. I wouldn't know otherwise. Your thoughts?

I have a lot of clunking as I drive down a bumpy road. Was told it was in the differential, but think it might be a coil spring not seating properly. Perhaps it's also lost it's "spring" as it's probably the original spring and 240k miles on it.

See pictures. I also was wondering if these springs should have a rubber mount, instead of metal on metal. All thoughts appreciated. tia.

The springs don't have a rubber cushion. They are set up correctly. If the ride height is correct, the springs are good.

Replace the sway bar bushings (cheap) and grease the sliding joint in the rear drive shaft (moly grease).

Hello,

I'm getting a large vibration almost every time I get into my truck and start out in the morning. Here are my observations:

1. Most likely to happen when vehicle is cold, maybe exclusively when cold.

2. It feels like a brake grabbing (refusing to let go in my case) as if there is a sticky substance on the discs. It also feels like a very sticky cv joint. It's a pretty major noise and vibrates the whole car.

3. Most likely to happen when wheel is turned hard one way. I back into my small garage, and always hug the wall on the passenger side. Vehicle sits with wheels hard to the left. As I pull out of the garage I get the vibration/noise.

4. Braking seems to have become more sensitive. Feels like the back brakes aren't working at all. If I apply a tad too much brake pressure it really want's to stop quick. Truck seems to be more nose down upon braking, but I could be wrong on that. I could be wrong on this point entirely (just my imagination). Do I need to bleed the brakes?


Other issues I'm experiencing, observations that may or may not be related:

A. Clunking parked. I heard a clunk in the front end when my wife jumped into the car. Car was off at the time. I can replicate that easily, usually when cold though.

B. Clunking driving. I get clunks in both front and rear end of vehicle while driving. Drive shaft is well greased (common problem, but not when greased).

C. Possible rear differential issues. I recently had both my rear axle seals replaced. The mechanic (who I've never used before) said the differential needs to be rebuilt, but at $800, he wouldn't do it, so I didn't. He said the differential was the cause of the clunk.

D. All the boots are in tack, not ripped open anywhere.

E. Front and back sway bar bushings are new.

F. I've never replaced any of the sway bar links. Vehicle has 242k miles on it.

G. No other suspension parts have ever been replaced, except for rear shocks, and the rear springs were replaced as part of that recall.

H. Power steering pump is original.

I. I haven't pulled the front wheels off in a while, but I can see that the brake pads are in place, pins are in place, and the discs don't show any abnormal wear.

Yes it's time for a new vehicle. But I do love this one and money is tight. I would much prefer to fix this one if it's not too difficult or expensive. All thoughts greatly appreciated. TIA.

I don't think bleeding the brakes will hurt or harm it. Flush the brakes if the fluid is very old, but I doubt it will help your problem.

4wd or 2wd? Automatic transmission?

Are the rear brakes correctly adjusted? How much lining is left on them at the thinnest place?

Have you every torqued the drive shaft nuts?

Have you recently greased (moly) the sliding yokes in the drive shafts?

Still thinking.

Thx for the reply. Great questions.

4wd, auto trans, greased the yolk, never have torqued the drive shaft nuts (don't know what those are, should I?)

Regarding the rear brakes, I doubt very much they are adjusted correctly. I think you are onto something here. About a month ago I had the rear drum off and spun back the adjuster because it apply slight braking pressure (which was probably caused by me yanking on the emergency brake which hadn't been used in years, and is now frozen stuck).

After driving it today I'm almost certain the shuttering is in the brake system. I was thinking it was a front caliper not releasing, at least that's what it feels like. Once I drive about a block or two, I can't replicate the problem.

Thoughts? thx again.

The clunk was caused by the dry splines. Forget the bearings.

Thx for the reply. The occasional clunks are back, not too loud, and not too frequent, but still there. There is no fluid leaking from the seals they replaced, or at least that I can see. Not sure I should worry about it as it doesn't seem to be getting any worse. I don't think I'll be taking any road trips with that vehicle any more.

If it was the splines, it will get better and eventually go away if they're kept greased with moly grease.

Torquing the drive shaft nuts is a maintenance requirement. They are on studs on the flanges at the end of the drive shafts.

Make sure the front and rear brakes have adequate lining (> 3mm at the thinnest point) and adjusted. If not done recently, flush the fluid. Check the runout of the front discs (side to side waver). Get the emergency brake working and adjusted.

Part of the clunking may be the u-joints needing grease. If you've greased them, they will also improve little by little.

Merged all relevant threads.

Wouldn't they have torqued the drive shaft nuts when they replaced the drive shaft seals? Or do they not come apart that way? Thx again for your replies, very helpful.

Which seals were replaced? Just the differential seal?

The answer is maybe and maybe not. I would just retorque them to be sure. It's hard to believe they torqued all the nuts, front and back.

Both rear drive axle seals were replaced. Do you know what the torque settings should be for those drive shaft nuts?

54 ft-lbs