I have a 03 Terminator and when I am cruising 2200 - 2500 RPM and let off the gas I can hear and feel a clunking sound and I feel the car sort of surge, sort oof like it is free-wheeling and then it is catching. This is in all gears, when I get in the throttle it is fine, it's just when I let out of the throttle or try to coast the car that this is happening. Chime in with anything I can check? Thanks!
That does not sound like a U-Joint problem to me. If you had a bad U-Joint and it was making a clunking sound it would give you a drive train vibration to. You would feel it in the gear shifter, and if it was bad enough in the floor and seat.
This is a good point. Jack up the rearend and put jack stands under the axle housing. Take the car out of gear and crawl under it and turn the driveshaft. If the U-joints are moving there's your problem.
I'm thinking now that it is in the rear end, gears maybe? What should I check for to see if it is in the ring and pinion?, the bearings, etc.
To check the ring and pinion gears just remove the rear cover and take a look. You are looking for scaling or missing peices on the ring and pinion gears. To check the pinion bearing crawl under the car and see if there is any up and down play in the yoke, Also twist the yoke to feel if there is to much play. Check the gear oil for metal shavings/chunks. If it is clean with some silver glitter that is o.k. Also make sure the gear oil is not mud brown or burnt smelling. If it is a mud brown you may have worn clutches in the carrier.
