99 expo eb shutering on incline

[shimpies9r]

hello went on trip today running 80-85 mph will running up incline you could feel truck shutering or viberating once lever or not as step incline felt fine any comment or suggestions would be great thanks

[shimpies9r]

ttt

[riproaringca]

Hey there!
My '97 was doing this this past fall. Determined that the rear differential fluid level was probably low: There were signs of it slowly leaking for about a month previous.
Check to see if yours is leaking. It may be as simple as taking the cover off, cleaning it, resealing it, and refilling with the proper fluid type and amount.

[JoeShmoe]

Is it throwing on a check engine light?

[vando002]

My friend's 98 started shuttering and the check engine light started flashing. I checked for a code and there were none. Got any suggestions for me?

[riproaringca]

Was there a 'check engine' light on or anything like that? No.

The leak was visible just by looking at the back axle of the truck. Easy enough to fix if it's summertime, or if you have an indoor facility in the winter. (You'll get dirty either way!)

Note: My '97 XLT 4x4 w/OD required fully synthetic gear oil. Make sure you use the right type of oil. There should be a metal tag on the differential casing which tells you what type of oil is needed. The tag will be held on with one of the casing's bolts.
I was also advised to use an additive (added to the gear oil within the differential) if my truck had posi-traction.

[JoeShmoe]

Originally Posted by riproaringca

Was there a 'check engine' light on or anything like that? No.

The leak was visible just by looking at the back axle of the truck. Easy enough to fix if it's summertime, or if you have an indoor facility in the winter. (You'll get dirty either way!)

Note: My '97 XLT 4x4 w/OD required fully synthetic gear oil. Make sure you use the right type of oil. There should be a metal tag on the differential casing. The tag will be held on with one of the casing's bolts.
I was also advised to use an additive (added to the gear oil within the differential) if my truck had posi-traction.

Does it matter how many miles the car has when talking about oil types?

[riproaringca]

I'd have to say 'no' to that mileage question.
I just used what the Owner's Manual and the metal tag on the differential housing told me to, along with the 'heads-up' from the auto parts store staff who told me about the additive for the posi-trac. (Something about the consistency of the oil needing to be perfect so that the posi-trac clutching action will release when it's not needed.)