dsnyderdsnyder
New Member
- Messages
- 1
- Reaction score
- 1
So I have a 1997 GMC K2500 4wd Suburban with a 6.5 Turbo Diesel. 187,000 miles. Runs and shifts fine. Smooth, no issues except...
On the interstate at high speed (over 70mph) if I let off the accelerator pedal on a downhill, as the vehicle wants to coast, I get a grinding sound out of the transmission. If I goose the throttle just a bit something engages again and the noise goes away. I can keep the noise from happening by decelerating slower, keeping just a bit of throttle on until I'm below say 60 or maybe 55. Then I can completely let off the throttle and let the vehicle coast with no noise.
So it seems like whatever is making the noise happens as the vehicle moves from Overdrive to coast to 3rd gear. No other noises or problems.
Deceleration at other speeds, lower than overdrive is fine, no noise.
The transfer case is newly rebuilt as are the drive shafts. Wheel bearing are new as are the CV joints.
Any thoughts on what this could be? I don't do heavy duty towing or hot rodding but I do like to cruise it on the interstate around the speed limit of 75 and we do have some significant hills in Arizona. I realize that at 187,000 we could be getting close to needing a rebuild on the tranny but I've heard this tranny can last a long time. Thanks in advance for any assistive knowledge.
On the interstate at high speed (over 70mph) if I let off the accelerator pedal on a downhill, as the vehicle wants to coast, I get a grinding sound out of the transmission. If I goose the throttle just a bit something engages again and the noise goes away. I can keep the noise from happening by decelerating slower, keeping just a bit of throttle on until I'm below say 60 or maybe 55. Then I can completely let off the throttle and let the vehicle coast with no noise.
So it seems like whatever is making the noise happens as the vehicle moves from Overdrive to coast to 3rd gear. No other noises or problems.
Deceleration at other speeds, lower than overdrive is fine, no noise.
The transfer case is newly rebuilt as are the drive shafts. Wheel bearing are new as are the CV joints.
Any thoughts on what this could be? I don't do heavy duty towing or hot rodding but I do like to cruise it on the interstate around the speed limit of 75 and we do have some significant hills in Arizona. I realize that at 187,000 we could be getting close to needing a rebuild on the tranny but I've heard this tranny can last a long time. Thanks in advance for any assistive knowledge.
