My '98 (V6 Auto) runs, drives, shifts like it is brand new...except for one thing--When coming to a stop, about one second after the wheels completely stop, there is thud felt underneath as if something is a little loose the momentum threw it forward. Same thing when I take off...a second afterwards I can feel the thud throw backwards. It is not a clank or clang, in fact, if I wasn't physically inside the 4R, I'm not sure I would "hear" anything. The transmission seems perfect, shifting smoothly at all speeds. I'm mechanically inexperienced, but it reminds me a little of bad U-joints I had on a manual S-10 twenty years ago. What should I look for?
What is causing this? [thud]
- Thread starter ljwd
- Start date
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quicksilvr
New member
Your driveshafts need greased. Are you 2wd or 4wd?
4wd. I just had it at a Toyota dealer a couple hundred miles ago, would they not do that as part of the normal oil/lube?
Is there an easy way to tell me how to do it?
I should have also added that when I shift from Park to Drive (or Reverse) that I often have the same thud...again, it sure doesn't seem like the transmission, but?
J-money$$$
New member
Most likely a dry slip yolk.
Get a grease gun, find the zirk fitting, apply grease with grease gun into zirk fitting.
Get a grease gun, find the zirk fitting, apply grease with grease gun into zirk fitting.
Stick Figure
New member
They SHOULD do it as part of the normal mileage service (don't know off had what mileage toyota recommends it being done) but I'm sure it gets skipped quite often to even be checked on a regular oil change/check.
SliderNH
New member
CHANGE THE REAR DIFF FLUID! I promise it will go away. I'm surprised the dealer didn't say anything about it when you had it in. Normally they will check it even with a oil change. Regardless, I'm speaking from experience. I know the noise/feel Change the diff fluid and it will be gone and you won't have to worry about it for another few seasons. Additional reason if you need it: If you can't remember the last time the diff fluid was changed, then it is time to get it done.
cj80cruiser
Senior Member
Usually that thud is the driveshaft.....never heard of it being the diff fluid before.
Phx994Runner
New member
Lube the driveshaft
I had this symptom in both my '99 Land Cruiser and my son's '99 4Runner. Used a moly (3%-5%) grease for the slip yokes. Did this over the course of three weekends and finally got rid of the symptom.
Over on the IH8MUD (LC) Series 100 forum there's quite a bit of discussion about how much to lube. The problem seems to be UNDER lubing the slip yokes. With both vehicles I had about the same process and results - first time greasing pumped about 20+ pumps into each slip yoke, nothing came past the seals but I could see some expansion. Drove a week, on a hot afternoon lubed some more, jumped up and down on the bumpers and began to get a bit of grease past the seals! Third weekend same thing, about another 10-15+ pumps.
Anyway, I think the thud simply comes from the lack of grease inside of the driveshaft creating a pocket if you will. That's where the symptom came from for us.
Don't forget to hit the other zerks with a good NLGI #2 Lithium grease just until you see the seals begin expansion.
I think most technicians, IF they bother to find all of the zerks in the first place:
1. do not use a moly-fortified grease on the slip yokes (helps with heat friction as I understand it)
2. throw a few pumps into the slip yoke and think "that's good" when in fact they are way under-lubing them.
Hope this helps.
I had this symptom in both my '99 Land Cruiser and my son's '99 4Runner. Used a moly (3%-5%) grease for the slip yokes. Did this over the course of three weekends and finally got rid of the symptom.
Over on the IH8MUD (LC) Series 100 forum there's quite a bit of discussion about how much to lube. The problem seems to be UNDER lubing the slip yokes. With both vehicles I had about the same process and results - first time greasing pumped about 20+ pumps into each slip yoke, nothing came past the seals but I could see some expansion. Drove a week, on a hot afternoon lubed some more, jumped up and down on the bumpers and began to get a bit of grease past the seals! Third weekend same thing, about another 10-15+ pumps.
Anyway, I think the thud simply comes from the lack of grease inside of the driveshaft creating a pocket if you will. That's where the symptom came from for us.
Don't forget to hit the other zerks with a good NLGI #2 Lithium grease just until you see the seals begin expansion.
I think most technicians, IF they bother to find all of the zerks in the first place:
1. do not use a moly-fortified grease on the slip yokes (helps with heat friction as I understand it)
2. throw a few pumps into the slip yoke and think "that's good" when in fact they are way under-lubing them.
Hope this helps.
GottaBeTRD
New member
i thought this was a normal thing? Iv'e seen a few threads like this before too. Back in the day when i worked at rental car branch i think about every 4th gen 4runner had the same "thud" during the same situations. Mine also does this sometimes too. so yeah i guess this is not normal?
econhonda
New member
If it's a full second after you completely stop, that almost sounds like it could actually be something swinging around. Would a dry slip yoke make the "thud" noise when letting off the brake when slowing? Anyway, just a thought to make sure the spare is nice and snug underneath the vehicle.
Thanks for all of the replies.
I had the rear diff changed a couple of months ago and it appears good. And, no, it probably isn't a full second after I completely stop...just seems that long because it is disconcerting to hear/feel anything after the wheels stop. I did check though and everything is good and tight underneath. I will definitely get to greasing and see what happens. Thanks!
I had the rear diff changed a couple of months ago and it appears good. And, no, it probably isn't a full second after I completely stop...just seems that long because it is disconcerting to hear/feel anything after the wheels stop. I did check though and everything is good and tight underneath. I will definitely get to greasing and see what happens. Thanks!
cj80cruiser
Senior Member
Landcruisers do it too. Go to the 80's section on ih8mud and it is covered in detail. It is also recommended to not over fill the slip yoke or it will put too much pressure on your t-case. That is highly debated however.
IanB
New member
When braking, things "bind" if there isn't enough grease, and they don't release until you let go of the brakes, so your foot dictates how long after you stop the thud comes.
I've been using Mobil1 synthetic grease in all my zerks, and still get this once in a while. Might be time to get a 2nd grease gun and some moly grease for the slip yokes.
cj80cruiser
Senior Member
There is a diagram somewhere on this site that shows moly only going in the DC joint on the rear driveshaft. I couldn't find it to save my life. All purpose goes in the slip yoke and the other u-joints.
I questioned it before since I'd always thought moly went in the slip yokes like you stated here. :shrug:
IanB
New member
I have a greasing point diagram saved on my work computer, confirms what you've said here. It's a PDF, and too big to post unfortunately, or I'd put it up.
cj80cruiser
Senior Member
That sucks, I went against my judgement and didn't put moly in the slip yoke...only in the DC. I don't know which way is right but it seems to work following the diagram so far.
