Looking for advice from my fellow Jeepers.

Just purchased a '05 GC Laredo with 4.7, Quadra-trac, 3:73 std. diff, 95k.
When I drove it on the hwy it howls like a banshee at 120k.
Would there be an additive I can use to quiet it down a bit? (Level is OK)

Also, would like to know what to flush engine with prior to my changing oil
to synthetic 5W20. Noticed some scum on dipstick.

Noticed that hyd. lifters are noisy on start-up. Any advice on an additive to quiet them down a bit?

Thank you, brothers, for any advice you may offer.
Cheers;
Ernie T.

 

Check front wheel bearings for howl

mine recommends 10W30 oil, could affect noise.

 

I typed a more detailed explanation but the site refused to post it.

 

Thank you for your reply.
The noise is def. coming from the rear diff.
Noise only when at 120km and only under load!
Fortunately I rarely drive that fast, (I too am an old fart!!!).
Ernie T.

 

Update on the diff. noise. Guess the level in the diff. was down a bit! Managed to squeeze in .5 litre of Hyper Lube which reduced the howl noticeably.