Buick
Newbie
Hey Guys, been a LONG time lurker on this forum, but I'm finally at wits end with my '99 K1500 Suburban. At highway speeds, between roughly 65-75MPH, there is a pronounced low frequency rumble. It is pretty loud, but difficult to determine where on the vehicle its coming from. Along with the rumble is a noticeable vibration, strong enough that it triggers interior rattles. The noise / rumble is non-existent at lower speeds and very much diminished above 75mph. I inherited the truck last year from my late father, who kept the truck exceptionally maintained. Of all things, my father was a career driveline engineer for General Motors (later Delphi/Nexteer), so its very near and dear to me that I figure out what's going on with HIS parts on his beloved truck!
Now the truck does have a lot of highway mileage, 289,000 to be exact. It is bone stock with the exception of factory 17" wheels from a late GMT800 truck being installed. Besides keeping up with regular maintenance items, last year he did some fairly extensive work before he passed.
Including:
- Pulled Engine to replace all seals, gaskets accessory drive items, fuel injection Etc. Runs Excellent
- All new engine/trans mounts
- Service front & rear diffs
- New shocks
- transmission & transfer case service
- new brakes (rotors & calipers, new shoes & cylinders in rear)
-4WD actuator and selector replaced
- New Rear Driveshaft & U-Joints (single piece driveshaft)
The noise was there before and was still there after the work he did (which was to primarily addressing other issues/leaks). Since taking over the vehicle, I've been frustrated by the highway noise as it's right at cruising speed. Changes in load on the engine/ driveline seem to have no affect on the noise. Its 100% speed related, this morning I even shutoff the engine at 75mph and coasted down to 60mph (neutral) and it had no affect, the noise "went away" once I dipped below 65mph or so. Engaging 4WD at highway speeds seems to add a little gear noise, but also does not alter the "rumble" in any way. In chasing the issue, I've started throwing parts at it this week.
Recently Replaced:
-Front Driveshaft pulled, (AutoTrak so front drive shaft always spins) u-joints replaced, re-balanced
-Both front wheel hubs/bearings replaced
- Brand new tires installed (had no affect)
-Drain and fill transfer case and diffs (fluid still looked new)
-Inspected trans mount, looks new
I've contemplated replacing the CV axles, but I'm very hesitant. They don't "click" when turning, or with 4WD engaged, so although they are old, I think they are perfectly fine. My dad's area of expertise and main product line were half-shafts, and time & time again he explained how aftermarket Chinese CV axles are total garbage. I'm concerned that throwing a couple hundred bucks at garbage aftermarket CV axles with neoprene boots that will tear within 6 months is just adding fuel to the fire...
Any suggestions of what to do next is greatly appreciated. Yeah I know, I can take it to a shop and throw A LOT more money at them to maybe figure out the problem, but I want to try to solve it myself. This truck meant a lot to my Dad, who always did all the work himself, and means a lot to me. I've read though just about every related thread without any smoking guns. Looking forward to the suggestions!
Now the truck does have a lot of highway mileage, 289,000 to be exact. It is bone stock with the exception of factory 17" wheels from a late GMT800 truck being installed. Besides keeping up with regular maintenance items, last year he did some fairly extensive work before he passed.
Including:
- Pulled Engine to replace all seals, gaskets accessory drive items, fuel injection Etc. Runs Excellent
- All new engine/trans mounts
- Service front & rear diffs
- New shocks
- transmission & transfer case service
- new brakes (rotors & calipers, new shoes & cylinders in rear)
-4WD actuator and selector replaced
- New Rear Driveshaft & U-Joints (single piece driveshaft)
The noise was there before and was still there after the work he did (which was to primarily addressing other issues/leaks). Since taking over the vehicle, I've been frustrated by the highway noise as it's right at cruising speed. Changes in load on the engine/ driveline seem to have no affect on the noise. Its 100% speed related, this morning I even shutoff the engine at 75mph and coasted down to 60mph (neutral) and it had no affect, the noise "went away" once I dipped below 65mph or so. Engaging 4WD at highway speeds seems to add a little gear noise, but also does not alter the "rumble" in any way. In chasing the issue, I've started throwing parts at it this week.
Recently Replaced:
-Front Driveshaft pulled, (AutoTrak so front drive shaft always spins) u-joints replaced, re-balanced
-Both front wheel hubs/bearings replaced
- Brand new tires installed (had no affect)
-Drain and fill transfer case and diffs (fluid still looked new)
-Inspected trans mount, looks new
I've contemplated replacing the CV axles, but I'm very hesitant. They don't "click" when turning, or with 4WD engaged, so although they are old, I think they are perfectly fine. My dad's area of expertise and main product line were half-shafts, and time & time again he explained how aftermarket Chinese CV axles are total garbage. I'm concerned that throwing a couple hundred bucks at garbage aftermarket CV axles with neoprene boots that will tear within 6 months is just adding fuel to the fire...
Any suggestions of what to do next is greatly appreciated. Yeah I know, I can take it to a shop and throw A LOT more money at them to maybe figure out the problem, but I want to try to solve it myself. This truck meant a lot to my Dad, who always did all the work himself, and means a lot to me. I've read though just about every related thread without any smoking guns. Looking forward to the suggestions!