So there I was, driving home from work minding my own business. I hit a bump (more specifically an expansion joint in an overpass), a horrible grinding noise ensues, I hit the next expansion joint on the overpass and the grinding noise ceases. I stop and check, no hot bearings, the driveshafts are tight and it drives normally. Once home I check more thoroughly, jacking up each tire, visually examining all the u-joints, no damage. So I think to myself maybe I oughta try four wheel drive. I back down my driveway, now a solid sheet of ice, and put it in four-wheel drive.........nothing. I try four low.......nothing. I can't imagine that it is the transfer case, or it would not go down the road so well (and quietly) in two wheel drive. As I said, no vibrations no new rattles. I still have the auto hubs (and as soon as I am done typing I am going to put the whole thing on jack stands and see where the problem lies). Has anyone had a similar experience with an auto hub dying? I am really hoping it is not t-case related. They use a lot of salt in Utah and I would hate to have to drive my Jeep to work in the winter (very clean '77 CJ7, no rust and that is very rare for a Utah Jeep). Any advice or past auto hub experience would be nice. Just for info, the Trooper has 284,000 miles and the hubs are original. I have never had trouble with them in the past, but I did just move the mountains and I have to use my four wheel drive at least two or three times a week. I will go check them out and post my findings. Okay, I seem to have omitted some critical information: 88 Trooper, bone stock except for the radio. So I put the thing on jack stands and pulled the hubs apart, everything seems to be in order <img src="/forums/images/graemlins/confused.gif" alt="" />. I have now reassembled and now 4wd works <img src="/forums/images/graemlins/confused.gif" alt="" />. I am at a loss <img src="/forums/images/graemlins/shiner.gif" alt="" />. I know it was not working before because my driveway is slick enough that I could let it idle in 4 low and get out and look. When I looked, only one rear tire was spinning. The front drive shaft was turning, but no front tires were turning. I figure that I will just get a set of regular locking hubs and eliminate the auto hubs as the culprit. It really doesn't look like they are the problem, they seem to engage just as they should, but there really is no other explanation. Any thoughts would be appreciated.

Yup, had problems with them. Brakes and auto hubs dont mix, thats all I have to say. But my problem was that I did have 4 wheel drive, but one of the hubs would begin to slip when there was enough torque and grip, thus losing the 4 wheel drive. It was also really noisy. I ended up buying a set of Warn premiums, I am really happy I did. Its the best thing I have done to it. Not to mention that if you ever need it, Warn sells a rebuild kit for the isuzu premium hubs and it costs about $25. They're worth the money in my oppinion.

I thought it should have at least made some noise, but it didn't. It just sat there with one rear tire spinning and nothing happening on the front. Now it seems to enagage just like it always has. Looking at the price of hubs, I think I will probably wait on the purchase of the manual hubs, maybe I can find a set in a salvage yard or on Ebay. Does anyone know what years the hubs will interchange through, and will Toyota units work? I am sure one of the hubs had to be slipping. Internally everything looked okay, no metal shavings, nothing that appeared to be unusual wear etc.. I am sure, since I am putting off the purchase now, one of the hubs will fail when I really need 4wd, but for $130, I will take my chances (I only paid $175 for the whole Trooper), $130 just seems a little high.

I believe your truck has to actually move forward a few feet to engage your auto hubs. So you driveway diagnostic (spinning rear wheel/front driveshaft) might not have been adequate to target your hubs. If everything dissassebmled/reassembled ok with no indications
of wear/breakage, I would claim no harm no foul. As for the noise. I have noticed that a nice chunk of ice or mud falling from the inside of the wheel well onto the the tire can sound pretty bad. In your case: 1st bump loosened chunk for rubbing/grinding, 2nd bump broke it off/away so no more noise. I would still go to manual hubs though!! Good luck

JD

I had the same thought about the ice, but as far as I know all the ice was gone from the truck. My other thought was that maybe since the overpass curves, somehow my 4wd lever may have gotten pulled a little and popped part way into 4wd for a moment when I went over the first bump and popped back on the second bump (no body lift or anything so I am not sure that is possible). I would pull the lever while moving to see if I can recreate the noise, but my Trooper preservation instinct kicks in and I can't bring myself to subject it to abuse that is not in the name of fun. I have found a better price on a new set of hubs, and I agree it is a good idea, but getting the finances approved by the wife can be difficult. Actually from what I can tell, the hubs will engage just by applying power to the front end. I could get them to engage by turning the front driveline by hand with the t-case in 2wd.

to help you out with a new set of hubs, you have a 17 spline cv's that can only be interchanged with isuzu. now look for 88-92ish pickup, rodeo, amigo, or trooper and anyone of those hubs will work. i enjoyed my set of asians until last week when i tried to pull a 1-ton chevy out of a ditch. drivers side hub exploded but, thanks to jcwhitney, i have a new set of superwhinch hubs that turn like a breeze. good luck.

Thanks for the 411 on the spline count, that is helpful, I will not waste my time looking for anything other than 'suzu hubs.I am going to keep my eyes open for a set of Aisins. I have found a set of superwinch for $120, and I know that one of the cheapie parts stores carries the same hubs and will beat the price by 5%. That is too bad the Toyota hubs will not fit, those things are ABUNDANT! If anyone has a set of hubs they would like to part with, let me know.