tfxpzeke01

First off, I have a 1997 Limited 3.4L 4x4 4Runner with a 170,000 miles. When I bought the truck in April 2007, with about 148,000, I was told it needed a main pinion bearing; yet money was tight and couldn't afford to fix it. It will making a roaring sound when letting off the gas, but quit when slightly tap the accelerator. This was when I first bought the truck. It soon after started leaking rear diff fluid and I had the front main seal replaced and then it started leaking again about 6 months later.

I was told that the rear diff was on it's way out and had excessive play(I think he said) in the "drive shaft", so I never worried about replacing the rear main pinion bearing and was looking around for a used/salvaged rear diff. Well, I just recently had the "3rd" seal put in and it almost immediately started leaking again right after installed. This was a different mechanic that did the work and one that my step-dad knows. He said he'd fix the seal for free if it was something he did, but he said the rear diff is fine, it just needs a rear main pinion bearing which I've known all along. One mechanic says my rear diff and is on the fritz and this one my step-dad knows says it's only the main pinion bearing that needs replacing.

Well, this past weekend, I started noticing a whining sound when either accelerating or keeping a constant speed accompanied with the normal "roaring" sound from the bad main pinion bearing when letting off the accelerator. It also seems to be worse over 55 miles per hour. I had to leave town today and was hitting 80mph on the Interstate and the whining sound was just so loud and annoying that it was almost unbearable. I thought maybe my diff fluid was getting low since it's still leaking. It was a bit low and had it topped off at Valvoline, but no change in the whining sound. What in addition to the main pinion bearing could be wrong and causing that horrible high pitch whining sound that just started this past weekend? Would changing the main pinion bearing stop the constant leaking? Would it be best just to junk this P.O.S. rear diff I have now and buy a used/salvaged rear diff from a junk yard?

netwt12

it would be easiest to buy another diff from a junkyard.

crolison

well i have a reputable and cheap gear shop and i would take it there, that would be around 150 bucks out the door.

But mos gear places aren't cheap, so i might price out a junkyard diff.

97ltd4x4

Sure sounds like a pinion bearing to me as well.The easiest thing would be to get one fron the junkyard....I would make sure you get the correct ratio....mark and count the rotation..from the pinion flange to the right axle rotation(right side spline on the junkyard unit)..i.e. one full rotation(wheel,or right side diff spline)=little over 4 rotations pinion shaft rotation,4:10 ration or whatever yours is.

Once you have your diff out,you could buy bearings,crush sleve,and have it all pressed out and back together quite reasonable,basically have a new unit.That is as long as the gears are ok.

trbizwiz

Stop throwing good money after bad. if the pinion bearing is bad and has been for a while, the rest of the bearings may be seeing extreme heat and vibration causing them to prematurely wear as well. If the gears are good a master install kit (bearings shims, crush sleeve, and such) will run $130 to $150. A used third will run $200 to $400. The labor on a master install kit will run about $150 to $200 from some of the vendors on this site. the install price is if you take the third off the truck and send it to them, shipping will run $60 to $80 each way. Worst case repair price is around $510 (if you need new gears add $150 to $200), or replace the third with a salvaged third worst case $460 (probably closer to $400 realistically if you shop around. Also the salvaged one is a crap shoot, but odds are it was not driven around with bad bearings for 8 months, and most yards will allow an exchange if the product is bad on initial install.
If you remove the third yourself and replace the new one your self, if you are somewhat mechanically inclined and have metric tools it will take 2 to 3 hours each way, off and then back on. I have personally done this with no prior experience and it is a little scary, but it feels great when you are done. Plus you get the satisfaction of knowing that you did something most people cant.

ARB4Runner

if u can feather the gas and the noise goes away its probably the gears going out to. just get a new or used 3rd and use RTV to seal it. the paper gasket from toyota usually leaks after a while anyway. be careful driving when it finally gives out the rear tires lockup. not the easiest thing to control going down the highway. if that happens u can put it in 4wd low and rip the teeth off the pinoin, put it back in 4wd high and u can limp it home. it will sound like someone is under ur truck with a jack hammer but it will get u home. i have driven like 50 miles on the highway like that. not recomended, but u got to get home somehow. if u want to regear it and have some lockers let me know. i have the full ARB setup geared 4.88. Best of luck, Zac

Maj

The bad pinion bearing is allowing the pinion to flop around and chew up the seal. That is why those keep leaking and a sign the bearing is getting worse since the seals are expiring sooner too.

The whining/howling from the rear end is because the gears aren't meshing properly due to the bad bearing. The gears are probably ruined now. Hate to say it but if you had repaired the bearing earlier it would probably have been much cheaper.

dbcx

X2 Damnit if I didnt work today you wouldnt of beat me to that one

Tofer

swap out 3rd and make sure your driveline is balanced....

tfxpzeke01

Thanks for the replies, guys! I'm assuming when you say "3rd", you are talking about "3rd member" which is just another word for rear differential? I just googled that. I know just the basics of vehicle repair/maintenance. Excuse my lack of terminology knowledge.

My stepdad told me that I needed to know the gear ratio in order to try and locate a used rear diff. Can someone dumb down how to do this? I have a jack. Would i just put a mark on my tire and drive shaft and spin the tire one revolution and see how many times the drive shaft spins? A little over 4 times would be 4:10 and a little under 3:xx? I know a guy that owns a wreck rebuild shop, so I'm thinking of seeing if he can locate me a used and in good shape rear diff., but finding out the gear ratio is my only hindrance at this time. Time is of the essence because the last thing I need to do is have my rear end lock up on me going down the interstate and injure myself and/or someone else. Thanks for the help guys. And, remember, you might have to dumb down some of the replies, so I can understand it..haha.

Yeah, I know this. It sucks that I let it drag out. Lack of money, time, and procrastination are my excuses.

waskillywabbit

iTrader: (-1)

Fix or replace the diff. Check the driveshaft u-joints. Seek professional help.

tfxpzeke01

Yes, FREE professional "mechanic" help is what I really need.

I think this forum is a little more advanced than I'll ever be in the vehicle world as I'll never be ripping my vehicles apart and modifying them. Google just brought me here, so I thought it was a good place to find some info. Thanks again for the recommendations and help, guys. I think I know what I need to do, now and have a bit more understanding than before I found YotaTech. If any of you care, I'll let ya know how it all turns out.

Meterpig

I had a rear end freeze up on a work rig. The resulting action was a nice collision with a tree.

I think you are playing with fire here.

dbcx

If you want to go the used route try here. It is jnkyard heavenit is a data base of all the junkyards put in your zip and pick your part. Its th same thing they use to checkother competition or if they have a part. As stated get the same ratio that you have now. You prolly shouldnt be driving it so pull the 3rd member and count the ring teeth and the pinion and dvide them it will give you exactly what you got.
http://car-part.com/

tfxpzeke01

Yeah, I know I shouldn't be driving it, but I don't really have a choice. I can't walk to work, grocery, etc. I'll just have to take my chances and hope for the best. I did go to car-part.com and located a Differential Assembly that I think will work. It's a 4:10. From what I've read online, everything tells me my gears are 4:10, but I won't know for sure until I discover it myself. I'm gonna just jack up one tire and chalk the tire and drive shaft and do it that way. I found this place and they explain how to do it as a few other places I've found. I don't really have the time to look at the ring and pinion teeth even though that's probably the most accurate method. I work 7 days a week(and, still have no money). I'm just gonna take it as easy as I can, leave early for work and drive as slow as possible until I can get it fixed within this week or next. There's isn't any jerking or clunking going on yet, just the whine sound. If I start feeling any unnecessary roughness in the rear end then I'm gonna park it wherever I'm at and just have it towed using my AAA card.