1994 Grand Cherokee all time 4wd problem

[Mombo]

1061938

1994 Jeep Grand Cherokee. 8 cyl, 120,000 miles. All-Time4wd. Seems when the wheels are turned to the far right or far left, and you idle around in a circle in a parking lot, there is a clunking right under the seat that you can feel through-out the whole front in. At first I thought it was a half-shaft (CV joint) Took it to a transmission guy and ole boy says" oh this is in the transfer case, seems it not disengaging from 4wd like it should, it should "float" until there is either a load placed on it, or one wheel slips, then it should engage. Yours is engaged all the time, whats why they front is shaking when you turn sharply to the right or left". Do not drive it " he says. Does anyone here know what this is? switch? Actuator valve? something steel deep inside the transfer case? He told me "two days and $900 we have it all fixed up for ya". Ide like to know a little more of what is is, and he was not real inclined to tell me the details unless I gave him the job (ouf course) lol Thanks for any info you can provide on what is causing this. Hes says it quite common with all-time 4wd systems and what have ya.[addsig]

 

[IcyFridge]

1061969

My friend had that problem with his Ford Explorer, but it was with hubs. What happened was that the hub bearings in the front wheels were worn out and broken so when you turn, the bearings grind and thump. Also, it could be something with the front driveshaft... I am just guessing here... [addsig]

 

[dingus]

1061999

check the vacuum actuators for the 4wd system...[addsig]

 

[remember5]

1062163

I'm also thinking it would depend of which system he has. I'm guessing "all time" is the Quadra Trac that I have with high and low, and in that system, I don't think the transfer case locks, it does have a viscous type coupling. I think the Command and Select track do actually lock the T case. I assume the U-joints are ok.[addsig]

 

[Bounty__Hunter]

1062222

Sounds like the viscous coupling in the transfer case is bad, not allowing the front and rear axles to spin at different speeds. Your jeep is doing the same thing as Wranglers do in 4hi on dry pavement, but they don't have a viscous coupling, so it's normal.

This will cause damage to your transfer case if not repaired. You may be able to find a used transfer case for way under $900, and they are easy to replace.[addsig]

 

[MudderChuck]

1062259

Like Remember 5 said, look real close at the axle u-joints. I mean from like inches away, with a flash light, dry u-joints will bind and really worn, they will thimp during a hard turn. Eventually they will vibrate at most any speed. The u-joint problem seems act up worse in any 4X mode, be it full time or part time.
A loose pinion or severly worn ring and pinion will also bind and stutter, but this rarley happens in the front.
If it does turn out to be something in the transfer, I´d disregard part time four wheel drive and just use it like a command trak and drive it till it dies.
Some of the select trak tranfers have the vicsious coupling some don´t they changed sometime in the mid 90´s I believe. There are about four or more different models of the selec- trak.

Indicators of a bad u-joint are rust dust around the rubber bearing seal and any kind of movement (at the seal) when twisting the axles by hand with the tire on the ground.[addsig]