4wd noise

[Hartleybl]

Hey everybody im new to the forum but not to s10's... this is my first crewcab... also first 4wd.... i hope someone can help me out with this.. when driving in 4wd... when accelerating in 4wd at 2500 rpms the truck makes a roaring noise... it didnt do this when i got it (111,000) and it just started roughly 2000 miles ago... its now got (120,000) also it does not make the noise in 4low just 4 hi... and also for some reason the t-case seems to be expelling fluid out of the fill plug... it is not over full... any help will be greatly appreciated... and also... i tryed to t-bar crank that made my front end roar.... and cv's start sling grease out of the inner boots... i really want it to sit a little bit higher... the stock measurements from ground to wheel well is 31.5 in front... 32.5 in rear... thats almost the same as my 2wd ext cab... again thanks for any help...

[Hartleybl]

well i just went to the store... and it has gotten a bit worse.. you can feel it not much but enough to know something aint right... only does it under acceleration.... starts at 2500 and continues through out the rpms... ive read other posts.. still cant quite figure it out.... it also does it in 2wd.. just not as bad...

[killian96ss]

Are you sure the "roar" is not the fan clutch being engaged. I know my CC and my ZR2 both made a loud roaring sound when the fan clutch engages in hot weather. The only problem I see is that it's not hot right now, so I'm not sure if the clutch can make that noise unless it's stuck in the engaged position. Can you duplicate the sound revving the engine while sitting still in park, or do you have to drive around to make the sound? Can you record the sound and play it for us?

Steve

[Hartleybl]

it's not the clutch fan it only does it under load its smooth in neutral all thru the rpms i got under the truck and checked everything earlier when it was daylight and added almost a whole quart of atf to the t-case... the filler plug lets fluid leak out of it... not the drain... the fill hole... i topped off the t-case and wrapped the plug with teflon tape and will keep an eye on it...... and also... does the front drive shaft have a CV joint inside that metal cup on the t-case side... theres a rubber boot inside but i cant fit more then the tip of my finger in there to check... it seems liike its got a little bit of slop or wiggle to it ( grabing it with hand and trying to move it up down side to side..) i guess who ever had this truck before me rode it hard and put it up wet... rear main leaks... rear output on tranny leaks....hopefully fixed the t-case leak... and fixed the front diff leak...

[crazycarl]

I think my truck is doing the same or similar. I'd describe mine more as a whine though. Right now it is only 4wd for me as well. I did replace my CV axles this spring... so not sure if fluid is low in the front differential?

[Hartleybl]

fluid is ok in differential i did check my t-case and it was a quart and a half low i filled it up and put teflon tape on the fill hole plug threads for some reason it leaks out of the fill plug... it wasnt really tight in the hole... threads didnt look worn but it wasnt a super tight fit... teflon tape took care of the loosness havent checked it in a week or 2 but its ALOT quieter putting it in 4-low... it was almost like a shotgun going off engaging 4-low but now its as smooth as ever ...i just re did the torsion crank and shackles i only raised the front up like a quarter of an inch below the 2 inch mark... because at the full 2 it roars at 60 plus mph.... and whines in 4wd at any speed..i cant figure out why if i max the passenger side torsion key out... the drivers side is less than half maxxed out but it went from 31 front fender gap to the ground to 33 ... well now a quarter inch less than 33.. and the back is 34.5 it was 32.5 ...if i could get both torsions to turn up equally it would lift it about another 1.5-2 inches... i cranked the drivers side to the max just to see how much different it was and it was almost double the passenger side
(edit)= i would not do it without the diff drop brackets tho... as i already need those and maybe even some ZR2 cv axels i think they are like 3/4 inch longer and from looking at the front of a zr2 today with a little bit more CV angle then i have it might be the way to go with a full out t-bar crank... but im not sure i still gotta look into it alot more

[crazycarl]

one thing I thought of after posting before, I also know my front wheel bearings are also on their way out, so not sure if that could contribute to the noise or not as well.

[Hartleybl]

thats a big possibility not sure how long the hub bearings last on an s10 4x4.. this is the first one ive owned.. others were all 2wd.. but at work we had a 2004 2500 gmc 4x4 with a service bed and we had to change the front hubs out 1-2 times a year and the truck doesnt even have 40k miles on it... but its a sand pit so thats really all it ever drives around in is sand... but the hubs are supposed to be sealed... so i dont know lol

[killian96ss]

Yes, worn out 4wd front bearings can make a roaring noise when they start going out. It is usually most noticeable when turning. I've had good luck with Timken brand front wheel bearings purchased from Summit Racing.

Steve

[Hartleybl]

thanks glad to know timken makes them for the 4x4 also... thats all i used on my 2wds

[ApproachMedium]

Timken and SKF make roller bearings for railroad trains. If they can handle a 200Ton freight car, they can handle your 4,000lb truck.

Also i would have got the truck up to the speed where noise is made and then put it in neutral and coast. if the noise is still being made, its probably related to the rolling running gear ( bearings, CV joints, U joints etc.) If it gets louder in turns its def bearings. It also might not be a bad idea to check your brakes as stuck calipers are a common issue with these crew cabs.

[Hartleybl]

still havent had any luck tracking down the noise my truck is making in 4wd... the only thing i can think of thats left is maybe slack in my t-case chain ? it only makes the noise when i let off the gas and start coasting.. its a whine similar to the sound it makes in 4low.... just not exactly the same stil no vibration just whines when coasting only in 4 hi give it the gas and it stops whining ..

[Hartleybl]

ok i found a video on youtube of a 4x4 ford that makes the same noise as my truck but he never replied what was wrong or how it was fixed... maybe if one of you guys hear it you could help me out lol i am stumped ... http://www.youtube.com/watch?v=NZu8o7rEFzU

[ApproachMedium]

Not the clearest audio on that, but it almost sounds like a differential hum. Have you checked the fluid levels on the front axle?

[Hartleybl]

last time i checked it was fine when the fill plug was removed it would run out a little bit... fluid looked brand new can you use synthetic lucas diff oil in these diffs? if so i have several bottles of it and would like to run the synthetic lube