Hello, my first time on so if I mess up, please let me know. Today, my 2000 4wd Expo acted up. I was doing a u turn and as I turned the wheel left she started shaking and vibrating. It felt like it was bearing down and shutting down. I immediately backed off the turn and pulled straight into a parking lot. I tested it turning the wheel slowly left and it wanted to still shake. Then it wanted to just stop moving forward. It would move if I goosed it a little so I pulled into a spot and proceeded to check my rear diff for leaks. Found none, and just changed the diff lube to Amsoil two months ago. Tranny fluid checked good on level and nice amber color. I let it sit for about a half hour, started it and it shifted smoothly into all gears. But it would not physically move forward or back with just idle speed, no gas applied. Put it back in Park then shifted again and it did move forward and back ok. Turned the wheel left to leave the space and it shook. Turned it right and no shake. Drove it home about five miles, all right hand turns except two at the end and it did fine.
Any ideas on what it might be? Has anybody had similar issues? Thanks for the help!

 

Oh yeah you screwed up big time. Here we use the term Expy, not Expo.

I would start by turning the wheel to the left and then getting underneath to see if the steering linkages are pressing on, crimping, or otherwise touching any wiring.

 

I'll try that. Thank you.

 

Welcome to the site, wattsk69!

 

Question, did you add the friction modifier when you changed the diff fluid???? I made that mistake on mine and paid for it dearly at the dealership a month later.

 

The modifier is only necessary if he has a limited slip axle.

 

I used Amsoil Extreme Pressure. I believe it was the 140-70 or 80 or 90, I cant remember, whatever was required. I did use some synthetic friction modifier to top off the diff because I was just a hair shy of the plug hole. I couldnt tell if you meant that I should have or shouldn't have used it. The Amsoil said I did NOT need modifier but it did say it was compatible with all synthetic and non synthetic lubes. Could I have damaged it by using it? What did you mean by " you paid for it at the dealership"?

 

I had the rear diff fluid changed at Jiffy Lube. They claimed what they used did not require the additional friction modifier Ford calls out for. A month later I had to have the rear diff rebuilt by Ford; they say the fluid change damaged my clutch packs due to the fluid change not adding the proper friction modifier. Jiffy Lube of course said it was not due to the fluid change, they showed me a bottle of what they used. I read the bottle and it claimed that it was full synthetic and was pre-mixed with friction modifiers. Long story short, if the diff is a limited slip type, make sure you used the right stuff before it causes damage to the clutch packs. Lucky I caught mine before it required the clutch plates to be changed. Per the dealer that would have cost me $2K instead of $600 for a disassemble and clean.

 

Can you guys tell me what I need to check to see if I have a limited slip diff, and if I do a fluid change what do you guys use?

 

Look on the driver's door sticker for the axle code then look it up in the chart on this page:
https://www.ford-trucks.com/article/...de_Chart_.html

 

Did it shake just sitting still with the wheel turned to the left? If it did, then I wouldn't waste time troubleshooting the rear diff. Lack of a FM doesn't cause a limited slip to shake the whole car, and it would occur turning both left and right. Besides, you said you added some FM.

Kinda sounds like you may be locked in 4HI, or you have problems with your steering rack. I'd concentrate more on the steering rack because you don't seem to have the problem turning right.

 

Thanks lwong, for now I will focus on the steering and related left side components. I cant say that I kept left turn pressure on while I was sitting still. I was fairly panicky because I got laid off and cant really afford any "big" issues right now. I will start her up and do some left hand turns in my yard to test.

 

Ok, so I took the girl out into my yard, I have a couple acres, turned left and right with no problems, shifted in to 4 Hi and 4 low easily. 4 Hi felt good, but 4 lo felt as if she was tied to tree while I was giving it gas. I'm going to do it again today to diagnose a little more. Does most everybodys 4 lo feel a little shaky when you turn left AND right on fairly solid ground? I usually use 4 lo in sand or dirt and never noticed before. But this felt very much like the shake I felt on the street when I was in A4wd.

 

I'll come right out and say I don't know the first thing about the 4 wheel drive systems on these trucks. Mine is 2 wheel. But I noticed in your last post that I think you are saying your truck was in all wheel drive. Do these have all wheel drive capability on the road?

If the answer to the above question is yes then I will assume that the transfer case uses a viscous clutch for road use. I know a bit about those from a GMC Typhoon I owned before the Expy. The symptoms you are describing are very similar to those in the AWD Typhoon when the viscous clutch gives out. The test for the viscous clutch, in a Syclone or Typhoon, was to make slow turns at full steering wheel lock. A bad clutch locks up and the truck shakes and hops while turning...........pretty much the same thing it would do with a conventional 4wd on the street I would imagine.

My point is, if these trucks use a viscous clutch in the transfer case then that might be something to look at. If they don't then I just wasted about 1 minute of your time.

 

Hey, thanks pinellas50. Any information is helpful because I am new to 4wd's also. That sure sounds like it could be it from your description. These versions basically have three settings, A4wd, 4hi,and 4lo. You leave the truck in A4wd for regular driving. If I am correct this is a computer controlled version of AWD but mostly relies on the rear wheels being driven. I will check to see if it does have the viscious clutch and if it does will have it checked out.
Thanks for your time and its extra appreciated considering I was born and raised in Pinellas county. Clearwater to be exact.