ratcheting/ whirring then Thump

[SensRanger]

Hi, I wonder if anyone has any clues to what might be happening to my truck (96 Ranger 4x4 xcab, auto, electric BW1354). Sometimes, seemingly randomly, usually while accelerating though, suddenly a whirring/ratcheting sound starts up. Sounds like it is coming from underneath the middle area (trans/t case/ rear driveshaft). Almost like a card-in-bicycle-spokes noise. It is tied to the speed of the driveshaft, I think. (sound slows down as I slow down). You can feel a vibration and hear the ratcheting, but otherwise it seems to drive fine. Then, once I get to like 10 mph, there is a loud Thump/Clunk (sometimes 2 quick ones) that you can feel thru the floor, and everything is back to normal, usually for many more drives. But it happened yesterday and today, after not happening for like a month. The previous times it happened, it was within 5 minutes of using 4x4 to get out of an icy patch, so I thought it might be related. But today and yesterday I was never in 4wd.
In a seperate diagnosis for front end popping noises while turning, I was told I need 2 upper ball joints, and the front axle u-joints are "seizing". I don't think it is related though, because I don't think the front axle is turning when the truck is in 2wd and autohubs unlocked...right? Could this noise be rear u-joints? t-case or hanger bearing? rear end (dont think so, the thump feels like it comes from the middle), trans?
All input appreciated!
ps. My search came up with whirring and ratcheting noise issues for auto-4wd t-cases, and usually when letting Off the gas. My problem is different, it happens when you are on the gas Or off, and I have the 1354 case (2wd/4wd high/4wd low).
Thank You!!

 

[AMMO_HOOAH]

I'm not an expert, but I'm totally thinking t-case. If you can have someone lie under or really close to the truck and drive very slowly forward or back. That really helped me find out what a noise was when my awd died.

 

[SensRanger]

Wanted to bump this in case anyone has any more ideas. Made the noise yesterday and today. Yesterday it suddenly started up the noise on the highway, I tried shifting to Neutral to see if that would eliminate the noise, but it did Not. Does this rule out the tranny? Sure sounds like thats where its coming from. Does the torque converter still turn with engine speed when the trans is in N ? Does the driveshaft still turn when the trans is in N? This noise is driving me nuts!!

 

[wood1]

It sounds exactly like what was happening to my '93 when the auto hubs were acting up. You could pull off your hubs then drive it around and see if that's what it is.

I changed the bearing in the auto hubs, cleaned them up, and changed the front outer u-joints before the problem was fixed. I think that the real problem was the seized u-joints putting pressure on the hubs when turning the wheel, it made the cam drag on the inside of the hub and I think tried to engage the hub... anyway, who knows. It stopped when I changed the u-joints.

The torque converter is bolted to the flex plate and that is bolted to the crank, so it is turning at the same RMP as the engine. The driveshaft will turn anytime the wheels are turning.

Good luck.

 

[MrShorty]

"Card in the bicycle spokes" noise was once considered a good indication of problems in the auto hubs. Pull the hubs and check for excess grease. Make sure they are unlocking when they should, locking when they should, and not locking when they shouldn't (if that all made sense).

 

[SensRanger]

Thank you for the replies. Based on your comments, and some further searching, it definitely sounds like I might have a hub that is trying to engage while driving in 2wd. Next time the noise starts up I will try switching to 4wd to see if that cures it, if it does, time for Manuals and new outer ujoints.
I will let you know.

 

[hunsaket]

My 94 Explorer is doing the exact same thing. I just changed all the front axle u-joints and repacked the front wheel bearings. When I put the hubs on and gave it a spin I noticed a similar noise just quieter. I test drove it and I seemed fine, but then today I made the noise while driving.

Did the new hubs help? I was thinking of new hubs or possibly that the noise could be coming from the transfer case.

 

[gijoecam]

Indeed, assuming you have the auto-hubs, yank 'em off, throw them away, and install a set of manuals. Sure, you lose the true shift on the fly ability, but you gain 1000% in reliability.

 

[hunsaket]

Is there a way to rebuild the auto hubs to make them more reliable? The reason I ask is that this vehicle is primarily driven by my wife and I like the ease of the auto hub for her.

 

[wood1]

There is a fix for the auto hubs, there is a small bearing in the end of them that will go bad after years and can cause problems, also a bit of wear can cause an issue and some guys have had to install washers to bring things into proper alignment.

I agree with GIJOE that the manuals are rock solid, but I'm lazy and I really like the ability to shift into 4wd and out again, only backing up a bit to unlock... If I ever get serious and lift mine/gear change/big tires I'll plan a manual hub swap as a neccessity, but for now the autos are staying.

Do a search, there is a rebuild thread on the auto hubs. It explains everything you need to do.

 

[SensRanger]

Old thread but figured I would post the fix in case people find this issue in a search.

"I think that the real problem was the seized u-joints putting pressure on the hubs when turning the wheel, it made the cam drag on the inside of the hub and I think tried to engage the hub... anyway, who knows. It stopped when I changed the u-joints."

Certain this was the case with me too. New outer u joint on drivers side cured the card in bicycle spokes noise. Auto Hubs work perfectly still on my 96 and while I dont go nuts with it, the truck certainly sees more trail, rock, and mud than 99% of vehicles on the road.

If you get the ratcheting whirring noise and thump don't listen to those who tell you to replace hubs until you're sure u joints are not the issue! 2 techs told me mine were fine but i didnt believe it when i started to get clunking while turning to go along with the occasional ratcheting episode. Finally get in there and it was rusted to sh*t and seized right up.