88 YJ 4WD problems

[Michael_h359]

Here are the symptoms, when i shift into 4WD the light comes on but driveshaft does not rotate, when i am in 2wd, drive shaft will rotate but no 4wd light. also the vacume hoses to the CAD system is only strong on one when i put into 4wd, i get no vacume when just in 2wd. Tell me your ideas but may it just be my shift lever just really bad out of adjustment? or are there other areas i should check?

Ty for all your help!

 

[Bounty__Hunter]

Check the vacuum lines from the transfer case to the front axle. If intact, the vacuum switch at the transfer case is likely bad.

The driveshaft will rotate slightly when in 2wd due to the viscous properties of the fluid, it's no indication of the front driveline being engaged. Fix the vacuum problem and then we'll diagnose any shifter adjustment problem.

 

[Michael_h359]

No the front drive shaft is engaged when the 4wd shifter is in neutral, it has turning power and not just barly spinning. But when the 4wd shifter is in 4wd ( the shifter pressed forward ) the front shaft does not spin. But the 4wd light will come one meaning the CAD system is engaged. I am assuming the CAD system is working properly but the shifter is just out of adjustment....?

 

[superj]

88 should have 2 wheel drive all the way forward. 4 hi is just back from 2 wheel drive. then it shifts to the passenger side for neutral and then all the way back for 4 low

 

[LGR]

J is right, 2, 4, N, 4L. I've got an 88 and my vacuum system was shot for that axle shifter fork thing and kept having leaks. I'm sure Bounty pegged it in the first response.

 

[Michael_h359]

Well thank you all for all of your input, This being my first jeep I was not clear of the sift pattern and that 4WD light coming on when really i was only in 2WD was a little confusing. After taking apart the CAD system and checking out the vacum hoses it was very easy to understand how it worked and put it back together the correct way. Seems that the hoses were incorrectly put on.

4WD light comes on when in 2WD and off when in 4WD but other than that 4WD is now working properly. Thank you all.