1998 Limited Grand Cherokee Radiator Problems after front end rebuild Front Differential problems as well

Have you changed the hub assembly or had the front differential checked out?

may need front end allignment

did you read the TSB on this car.
see alldata.com and click TSB tab.
recalls and service issues are there.

This is just a breather tube for the differential. It usually runs up and connects to the fender well. you can tie it to anything up high enough.

This hose you refer to is the breather tube for the differential. It connects to a fitting at the top of the differential housing and runs up the back side of the radiator so you won't run the risk of water entering the differential if you submerge the front axle in water. Reconnect the rubber hose to the fitting on the differentail.

First thing to test is to see if the front driveshaft is getting engaged from the transfer case. With the vehicle in 4x4, and engine shut off, and in park, crawl under and try to turn the front driveshaft by hand. The driveshaft looks like a pipe that runs from the transfer case, located just behind the engine/transmission, to the front differential. If it rotates by hand, there is a problem with the transfer case. Some Jeeps have a vacuum actuator on the front diff that slides a collar inside the axle tube to engage it. I will watch for you findings, and you can leave me another message, and I will be happy to chat back with you on your findings.

You need differential carrier and pinion bearings. Jeeps had many problems with the differentials in these years.

It sounds like the reverse band is out of adjustment. Three things can cause this, reverse band, front clutch and the overdrive direct clutch. To test the band, drive the truck in manual low up to 25 mph. Then let off, if the transmission doesn't pull the engine down, the band needs adjusted. If the front clutch is the problem, 3rd gear will be act weird too. The only test I know of for the overdrive direct is to inspect it, so process of elimination will have to work. Hopefully the problem is the band, because you can pull the pan, service the trans, adjust the band, and be done. Any of the other problems and you are looking at a rebuild. Good luck.

The 99 Jeep Grand Cherokee was prone to bad diff bearings because they changed the plant where they were made. The new plant used inferior materials. The only way to fix it is to replace and set the diff clearences.

check the differential fluid in the rear differential. if the fluid is low, add fluid and see if the noise is still there, if the fluid level is ok see if the fluid appears metallic, if it is metallic looking or excessively thick it would be a good idea to have the bearings checked out. i am in the process of rebuilding a front differential on a 98 jeep grand cherokee for the same problem. the bearings inside the differential on the carrier and pinion gear were worn out causing a humming noise. if the wear is excessive the gears might also need to be replaced