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J Kimmel
02-05-2009, 10:27 PM
so I picked up a clean 98 4Runner...pretty pumped, I've got a good camping rig for the summer that isn't tied to my trailer :)

I've got a noise from the rear, kind of a light thunking. I thought it was the driveshaft, pulled it and the noise went away, but I also drained and re-filled the rear end to eliminate that too. Rear end fluid was fine, ds checked out fine too. My next thought is drain the t-case and see whats in there. So the question:
Its an automatic, 3.4 engine. Is the t-case lubricated by the transmission fluid? Or is it just plain ole 90 weight?

I suppose I need a haynes manual :)

nakman
02-05-2009, 11:03 PM
I'm almost positive it's gear oil, but I would start searching Yodertech, here's one to get you started http://www.yotatech.com/f2/99-00-transfer-case-swap-onto-96-98-a-77426/

congrats on the new ride! pics, man.

Uncle Ben
02-06-2009, 12:42 AM
so I picked up a clean 98 4Runner...pretty pumped, I've got a good camping rig for the summer that isn't tied to my trailer :)

I've got a noise from the rear, kind of a light thunking. I thought it was the driveshaft, pulled it and the noise went away, but I also drained and re-filled the rear end to eliminate that too. Rear end fluid was fine, ds checked out fine too. My next thought is drain the t-case and see whats in there. So the question:
Its an automatic, 3.4 engine. Is the t-case lubricated by the transmission fluid? Or is it just plain ole 90 weight?

I suppose I need a haynes manual :)

I just happen to have a spare lefty case (99) if ya need one.. Don't ask why and I won't have to Lie! :rolleyes: :lmao::lmao: trans should be an A340E But if it's a A340F the t-case is pressure lubed from the tranny. Haynes is for J**p guys....get serious and get a FSM!

DaveInDenver
02-06-2009, 05:55 AM
I just happen to have a spare lefty case (99) if ya need one.. Don't ask why and I won't have to Lie! :rolleyes: :lmao::lmao: trans should be an A340E But if it's a A340F the t-case is pressure lubed from the tranny. Haynes is for J**p guys....get serious and get a FSM!
Wouldn't it be a A340E if it's 2WD and A340F if it's 4WD? That's the way I'd always heard and it's that way in our 4Runner, A750F for 4WD and A750E for 2WD trucks.


Anyway, the transfer case on both is 75W90 GL-5 according to the 2000 Tacoma owner's manual and the technician's quick reference. That's what ours takes still, too. The t-case in our '05 is the multi-mode VF4AM with the torsion center diff, takes a quart and half of 75W90 gear lube and it's behind the A750F. What is different is that the A750 does not take Dexron-III like the A340 did, it uses some special T-IV ATF.

http://www.ncttora.com/fsm/2000/Owners%20manual/80%20Specifications.pdf
http://www.ncttora.com/fsm/2000/Technicians%20Reference/Fluid%20Specs.pdf


I've mentioned it before, TTORA and their online FSM, yeah!

http://www.ncttora.com/fsm/

J Kimmel
02-06-2009, 08:10 AM
looks like I have more searching to do, man this thing is way more complicated than my truck:rolleyes: I searched yotatech last night, thanks nakman but didn't really fine much. Not too much in the way of tech there...but i did find a thread about a guy who thought his transmission was bad, only to find out he had it in nuetral:)


oh and I think pics would be boring...its pretty plain jane, just a white runner :) I am going to put a set of sliders on it and thats all the mods for me :)

SteveH
02-06-2009, 09:23 AM
The owners manual should tell you what fluid to use.

Also, given the shockingly wimpy ball bearings in the rear axle, be sure you jack up the rear of the truck and lift up on each rear wheel to check for play in the rear wheel bearings. My left rear wheel bearing failed at 120K-ish and was completely fried. While I got the typical 'bad wheel bearing' sounds, your sound may result from the same thing.

Too bad Toyota cheaped out (or did this for gas mileage) and eliminated the roller bearings used in 1st gen 4Runners and replaced them will ball bearings in 3rd gen. I don't know what 2nd gen used.

Steve
'98 4Runner, 145K

Red_Chili
02-06-2009, 11:36 AM
Too bad Toyota cheaped out (or did this for gas mileage) and eliminated the roller bearings used in 1st gen 4Runners and replaced them will ball bearings in 3rd gen. I don't know what 2nd gen used.

I had no idea. I put in the same bearings as always on my Taco axle going under the '93 DD. Virtually the same assembly as the early trucks except 3/4" wider and using thinner steel in the housing (thus leading to spring perch damage with wheel hop - not an issue with a coiled 4Runner).

You sure it didn't change for the 4th gen, not the 3rd?

J Kimmel
02-06-2009, 12:17 PM
Geez I had no idea either...I figured since it was a normal 8" with the e-locker that it was same same, guess not. I'll jack it up this weekend and see.

so then, anyone press the bearing off themselves, or do you need a special tool or press for it?


hey on a good note I got my re-worked head back so I can finally start installing EFI into my crawler :)

DaveInDenver
02-06-2009, 12:25 PM
I had no idea. I put in the same bearings as always on my Taco axle going under the '93 DD. Virtually the same assembly as the early trucks except 3/4" wider and using thinner steel in the housing (thus leading to spring perch damage with wheel hop - not an issue with a coiled 4Runner).

You sure it didn't change for the 4th gen, not the 3rd?
I've heard that the Tacoma and 3rd gen 4R rear wheel bearings were balls rather than tapered, too.

But I don't know first hand as I haven't taken apart the 2005 and my '91 still used tapered roller. Could be that the external dimensions are the same, just that they used ball bearings from the factory. Also could be a difference in trucks and 4Runner, being that the Tacoma axle was made here in the USA by Dana and the 4Runner axles were still made in the motherland.

Just throwing out what-ifs to obscure the question since we've personally missed out on Toyota offerings spanning production from 11/1990 to 9/2004.

Red_Chili
02-06-2009, 12:55 PM
You sure those are tapered rollers? Wouldn't that require some preload?

FWIW, ball bearings are a fine application for rear axle bearings, but they sure don't like leaky axle seals. Neither do brakes.

To change them you need some sort of jig and (I would recommend) a 20-ton press. I was successful using my 12 ton HF press, ONCE, but SeldomSeen discovered its limits with his. No problem, I was able to weld it back together...
:rolleyes:

I have most of what you need made out of an old axle. You may borrow it for a sixpack or something, as long as the jig has attached to it a satellite tracking system guaranteeing it makes it back to me.

J Kimmel
02-06-2009, 01:07 PM
might take you up on that. Question though, why do the bearings not like the oil? Seems they would but, I dunno. I will say for certain though I am pretty positive they are leaking, as the backing plates are damp, and the brakes work great so it isn't a wheel cylinder.


You sure those are tapered rollers? Wouldn't that require some preload?

FWIW, ball bearings are a fine application for rear axle bearings, but they sure don't like leaky axle seals. Neither do brakes.

To change them you need some sort of jig and (I would recommend) a 20-ton press. I was successful using my 12 ton HF press, ONCE, but SeldomSeen discovered its limits with his. No problem, I was able to weld it back together...
:rolleyes:

I have most of what you need made out of an old axle. You may borrow it for a sixpack or something, as long as the jig has attached to it a satellite tracking system guaranteeing it makes it back to me.

DaveInDenver
02-06-2009, 01:21 PM
You sure those are tapered rollers? Wouldn't that require some preload?
Duh, I'm thinking of the front. :doh: I understand that the Tacoma doesn't use tapered roller bearings at all, right?

My mind is mush today, although I did figure out something cool this morning. How to parse strings from a VHDL component's stim file (the component is just an ugly hacked together op code processor that runs my script of commands) and echo it into my Questasim simulation. That makes me happy cause I can add keyword comments that I can use to search through the 100,000 friggin' lines of high-Z and resolved to 'X' warnings in the log file. I'm such a dork. It popped into my mind how to do it at about 3AM and I never got back to sleep, so I got into work really early this morning.

SteveH
02-06-2009, 01:54 PM
The '98 is a 3rd gen (according to my understanding of generations). Replacing the rear rear wheel bearing involved (with my buddy at the dealer) removing the axle, and cutting off the ABS sensor and a few assorted press-on rings and spacers. You can technically remove these pieces on a press, but the dealer guy cuts them off carefully with a die grinder, to not nick the axle. It's very tough to set up the press to press off these pieces without damaging them or the axle. Obviously, he's not paying for the parts, either. Afterall this is off, you can press off the wheel bearing. It required some press skill, so I don't recommend this to someone with a bench vise in their garage.

Total parts price was $150 for a new bearing, spacers, ABS ring, oil seals, etc. I think this bearing is not lubricated by axle oil, because there's an oil seal on both sides. I have the defective bearing, and this ball bearing is quite loose and noisy as you spin it in your hand. The cage holds the ball bearings quite far apart, so that only a few bearings at a time are bearing the vehicle weight - hence my opinion of a poor design.

The way mine failed is that I was returning from a 4000 mile vacation and last 250 miles, I hear a 'bad bearing' sound. Driving 80 with a 200# camper may not have helped. Upon putting the truck on a lift and putting it in gear and letting the rear wheels spin, it was very obvious by sight and sound that the LR wheel bearing was shot. I did not replace the RR bearing and we'll see how long that one lasts. If it were cheaper/easier, I would have done them both, but hey, the truck could be totalled by some idiot tomorrow, too.

I did not investigate (but should have) if the ID/OD of the 1st gen tapered bearing were the same. If so, you might be able to retrofit a 3rd gen axle with tapered roller 1st gen bearings. This would be a nifty upgrade.

Final note - I never had any oil leakage with this bearing failure, so by catching it early, it saved buying a set of brake shoes (which are typically contaminated by gear oil during a bearing or seal failure).

Steve

SteveH
02-06-2009, 01:57 PM
Correction to posting #13 per the earlier comment - 1st gen rear axle roller bearings are straight, not tapered. My mistake.

J Kimmel
02-06-2009, 02:03 PM
sounds like a disaster...:rolleyes:hope mine is better than that, we shall see.

Red_Chili
02-06-2009, 03:19 PM
I dunno, I regularly hear of 200K successful miles on 3rd gens, and 150K failures on 1st and 2nd gens. Luck of the draw IMHO. FWIW all my motorcycles use sealed balls too, and there are some serious side loads on them. Not sure I'd call them junk, but Robbie or BVB or someone could speak with more authority.

Yeah, they hate gear oil. Gear oil from leaky axle seals washes past the bearing seals and carries in grit, washes out grease. Dead in short order.

You are right on the front bearings Dave. No more tapered rollers. :(

Of course the Chili no longer sports ball OR roller bearings in the rear. Tapered 4 corners baby. 11952

AFAIK the older and newer bearings are identically sized. I had no idea there was a difference. I might just have to pull a seal on the new ones in my garage and have a lookeesee.

DaveInDenver
02-06-2009, 03:37 PM
I dunno, I regularly hear of 200K successful miles on 3rd gens, and 150K failures on 1st and 2nd gens. Luck of the draw IMHO.
I agree, normal manufacturing variance like anything. Just that Koyo bearings generally have less part-to-part variance IME. I'm at 207K on my original rears and have been kicking around doing the R&R just 'cause this summer since the truck's been noisier going down the highway since Rubithon (haven't isolated it to tranny, xfer, tires, just a lowish hum that I can't quite convince myself is the M/Ts). I might just be jinxing myself.

J Kimmel
02-06-2009, 04:14 PM
well I will jack it up this weekend and see. If it is the bearings I think I will gather the parts and just pull the whole assembly out and tear down to R&R it.

Red_Chili
02-07-2009, 01:30 PM
I agree, normal manufacturing variance like anything. Just that Koyo bearings generally have less part-to-part variance IME. I'm at 207K on my original rears and have been kicking around doing the R&R just 'cause this summer since the truck's been noisier going down the highway since Rubithon (haven't isolated it to tranny, xfer, tires, just a lowish hum that I can't quite convince myself is the M/Ts). I might just be jinxing myself.
If you are at 207K on your original gears as well, or close to it, you might consider pulling the diff and checking the carrier bearing preload too.

http://www.gearinstalls.com

J Kimmel
02-07-2009, 02:27 PM
If you are at 207K on your original gears as well, or close to it, you might consider pulling the diff and checking the carrier bearing preload too.

http://www.gearinstalls.com


I think once the weather is nice I am going to pull the entire axle and go through it top to bottom. With 212K on the clock it doesn't seem like a bad idea :)

DaveInDenver
02-07-2009, 03:06 PM
If you are at 207K on your original gears as well, or close to it, you might consider pulling the diff and checking the carrier bearing preload too.

http://www.gearinstalls.com
The bearings in the diff are much younger, I'm pretty sure I had Robbie replace them when the gears and lockers were installed. Yeah, pretty sure.

J Kimmel
02-19-2009, 08:09 AM
thought I would toss out a quick update...

Had front range go through the driveshaft, like I thought when I pulled it, all was fine. The re-lubed and re-balanced it and that was it. While I had it out, I drained and re-filled the rear diff too. Nothing out of the ordinary was in the old fluid I drained either, not under filled, etc.

So the re-filled diff and re-balanced shaft are back in, and the noise is gone, so it seems all is well for now :)


oh and the best part...the CE light has been on since I bought it a few weeks ago. I haven't gotten around to diagnosing yet, but I guess it got bored cause halfway home last night it turned itself off, and even driving to practice later on and then back home, no more CE light :D

Red_Chili
02-19-2009, 09:24 AM
Check your canister VSV. Common failure around that mileage. DAMHIK. Darn easy to fix though. Pull the code.