Team420

I could use a lil help from the differential experts... I have a 4.88 in my 93, Its got a very loud howl, cant even hear myself think! It starts right around 25mph, and just gets louder with speed, let off the gas, and it goes away completely, but... If im giving her just a lil throttle, say just enough to maintain speed on flat ground, its really loud. The 3rd has always had a slight whine to it, but it suddenly got much worse.

I guess my question is... Does this sound like something that can be adjusted via the adjusting nuts? Or do I need to change my pinion depth ? Or could it just be my carrier/pinion bearings? How does one check carrier/pinion bearings anyway?

The 3rd is out of the truck now, no metal shavings or chunks in the oil, and everything looks ok. I have messed around with these 3rds before, but never because of this type of noise, its always been a little howl, that I could adjust via the adjusting nuts on the carrier, this noise is NOT the typical rear howl that I have experienced with these rigs...

Any and all help/suggestions would be greatly appreciated!

Btw... I know the easiest thing would be to just find a used 3rd... however, finding one in decent shape around here for a reasonable price, is near impossible, and as with most people these days, funds are very limited!

waskillywabbit

iTrader: (-1)

You sure it's the third and not a ujoint?

:wabbit2:

TexFF

Not hijacking your thread, mine's whining exactly as you describe. I have a 5 speed. When I left off the gas, it goes away 100%. Sounds like the whine/howl from big tires. Somebody set-up the rear end wrong(PO installed new R&P) & the pinion had a lot of slop(up, down, left, right) so I had my mechanic install a new install kit(ALL new bearings, seal, etc.). It still whines just like it did before but I know it's installed properly. Will a u-joint whine? I've never heard 1 whine before & I've been thru a lot of them on other vehicles.

Team420

New u-joints.... And... I never heard a u-joint make this type of noise before.

There is no vibration, no clunking from the shaft or 3rd. I can however turn the shaft quite a bit b4 it engages the wheels, so, there is some slop in this 3rd. Truck accelerates fine, and smooth. I was originally thinking wheel bearings, but the sound dosent change with corners or anything, its all throttle related... on throttle just slightly, and its loud as heck! during acceleration, it quiets a bit, but is still very audible, let off the gas all together, and it sounds perfect... this is what is leading me toward a drive line/rear end problem.

The slip yoke on the shaft has a lil slop to it as well... maybe thats causing the noise?? I tried to swap the shaft from my 94 5spd, but it seems that shaft is an inch longer than the auto shaft, and will not fit. Coulda swore the shaft thats in it was from a 5spd, but my 94 shaft just wont fit it...

motocrossaddict223

this is kind of dumb because i think you're smart enough to cross this off your list first thing but does your third have enough oil in it?

Team420

Not a dumb question at all, but yes, that was my 1st thought as well, and it was full, the oil was a lil burnt and stinky, but thats to b expected after pulling my 84 chevy bed box trailer with firewood all winter :-)

As I said... the 3rd is now out of the truck, and upon close visual inspection, all appears fine... no chipped teeth or anything that I can see...

motocrossaddict223

yea haha i just know i sometimes miss the obvious answers so i waas just throwing that out there. And i am by no means a differential expert, im so afraid to mess those up that is the only thing i pay someone else to do on my trucks, but ill stick around this thread and see if i can gain a little diff knowledge . Good luck!

Team420

Ya, I'm no expert on them for sure, but I could set up a diff with all brand new parts... thats not terribly difficult, if u can read, and follow directions....

This noise coming from my very worn and used 3rd, has me baffled tho.... As I said... its not the typical "howl" that is so common with these...

InternetRoadkill

Check the bearing preload and gear lash.

Duffdog

Hey um, you said that the slip joint on the driveline has slop? How much exactly? 1/8"-- 1/4"? more?

Because I just had this type of noise coming from somewhere under the truck, I thought it was the diff, but I do my own diffs and mine was tight and perfect. I shook the driveline and saw that the tailshaft of my t-case moved about 3/16" of an inch up and down inside the case. When I took the back of the t-case off, I could see that the roller bearing had been wobbling because of the driveline and causing some crazy wear on the output shaft. Since the only thing that could move around was the driveline, I'm thinking that is what is causing the noise.

worth checking out that bearing.

250000_yota

Have you had a chance to check the pattern or check backlash?

Team420

Sorry I havent had a chance to respond on this.

I tore it apart this weekend, gear lash is off a bit, and is contibuting to some of the howl, The noise I was experiencing tho, was caused by the pinion shaft/bearings. The Idiot the owned it before me, had apparently replaced the pinion seal at one point, and cross threaded the nut when reinstalling, so the pinion was not tight. It felt tight because of how the nut was crossed. I had to make a tool out of 6' angle iron, and drill holes in it, to bolt it to the companion flange to hold it still, then take my 30mm socket, and 3' breaker bar, as well as a 6' pipe to break that sucker free... Didnt realize it was cross threaded till I went to put it all back together... boy was I pissed!! Ended up chasing the threads, and got the nut to thread propperly, but the damage has already been done, both pinion bearings are toast, I'm try cranking the nut a lil tighter to see if that helps for the time being, but it looks as tho I am gonna be ordering some bearings.


Thanks for the help and suggestions guys... the guy that owned this 3rd before me really screwed up!! How the heck do ya cross thread a pinion nut any way

Team420

Anyone got suggestions as to where to order these bearings? Approximate cost?

Anyone got part #'s for these? I'm thinking eastern bearing is the way to go... Napa wants $140 for just the 2 pinion bearings, eastern has koyo bearings (O.E.M.) and I'm certain they will be a whole lot cheaper than napa....

Team420

Another quick question... are the pinions the same in all v-6 rear 3rd's? and the ring gear is what changes ratio? Asking cuz I have a perfectly good 4.10 3rd in my garage, if the pinion has the same # of teeth, and is the same size, theres no reason I couldnt just swap that in... right? I no longer have my p/u that had 4.10, so this 3rd is useless to me otherwise....

TexFF

I bought a kit that had every bearing, bushing, gasket, etc. for the ENTIRE rear axle for $185. Replaced them all. It didn't get rid of my humming/buzzing/whining sound, though. I believe you are correct about the ring being the 1 that changes the ratio.

Team420

ya, I called a couple different places... Toyota want $178 for the inner bearing, and $71 for the outer.... They are koyo bearings... and eastern bearing says they can likely get them to me for under $100, BUT... I need part #'s off the bearings themselves.... Which I could not find... Advance auto want under $100 for the bearings, but they cheapo national bearings... I want koyo (O.E.M.) Napa has dana bearings, so not interested there either...

I'm about to go tear the 4.10 apart, and count teeth on the pinion.... will report my findings after!

TexFF

I got my kit from a high performance drag racing shop in my town. I THINK it was a Yukon Gear set.

Team420

Tore the 4:10 apart... 10 teeth on the pinion, 41 on the ring... 41/10 = 4.10

I'm going to assume, that the 4:88 has 10 teeth on the pinion, and 49 on the ring... 49/10 = 4.9, but I wont know for sure, till I get that 3rd out and apart again...

This is just pretty much a "notes to myself" thread at this point... But maybe it will help someone in the future...


Also going to note that the 4:88 had koyo bearings, the 4:10 has NSK bearings.... hmmmmm

BigSwole

My rear end has done the same exact thing.

So i put on some 35" MTs and you cant hear it over the tires now.

ZUK

iTrader: (1)

Should find the bearing part numbers here....
http://gearinstalls.com/bearing.htm