SunlitComet
OBS Jedi-Do Good
Do I understand your to say that when you switch to 4x4 the noise goes away? If so when you replaced your t-case did you use the existing shift motor or a new one?
97 tahoe, grinding noise
- Thread starter nhbluevip
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
SunlitComet
OBS Jedi-Do Good
you should be able to do highway in 4hi but not low if you don't want valves flying out of your hood like a sparkler. Just do it a short period of time on drive payment. Until you figured out the noise I would not shift on the fly at speed just yet. It maybe worth trying.
If the shift motor is the existing one my thought was something was wrong with its encode or the gearing inside causing a partial engagement. Just a thought.
If you have the nv243 t-case (RPO code NP1 I think-Check on the inside of your glove box face.) I have about 2 dozen papers on that system. Including T-case control module tech data. I can only fax it right now though.
If the shift motor is the existing one my thought was something was wrong with its encode or the gearing inside causing a partial engagement. Just a thought.
If you have the nv243 t-case (RPO code NP1 I think-Check on the inside of your glove box face.) I have about 2 dozen papers on that system. Including T-case control module tech data. I can only fax it right now though.
I forgot to mention, the old tranny that was in it had a hair line crack in the case, just in front of the pan, which obviosly leaked bad and I believe burn out the tranny over time. Im thinking what ever this grinding vibration is, may have been what caused the crack before. I would like to figure this out, before it cracks another tranny or t-case.
SunlitComet
OBS Jedi-Do Good
In that case it has got to be somewhere from the driveshafts outwards. Rings or pinions bearings or teeth - axle bearings. I do not know if a a malfunctioning locker could do it but maybe the front axle shift mechanism. Maybe something hitting the reluctor rings for ABS on the front wheels. Or maybe a plastic body piece hitting a moving part at speed. The sound is probably just traveling through the parts that will carry it the easiest. Can't think of much else unless you have it put on a rack with some one inside on the throttle.
Agreed. I have had the rear end opened up to do the axle seals, all looked good. I agree it has to be something with the front, and vibrating the front axle? I don't understand why it woud go away the minute it is put into neatral, and your coasting?
SunlitComet
OBS Jedi-Do Good
Is there any evidence that maybe a collision with parts has shifted the mounts on equipment cuasing binding problems. Page 98 of the document below might help if you want to do some basic measurements. There are more I just don't have them now.
http://www.sunlitcomet.com/pdf/auto/ck.pdf
---------- Post added at 06:18 PM ---------- Previous post was at 06:11 PM ----------
Wear on the driving side of gear tooth or synchonizer face and none on the other face that makes contacts when coasting with no force.
Something like that.
Last edited:
