4.11's and G80 posi in 2005 AWD

[LiftedAWDAstro]

Yeah nice and quiet so far! I only put about 5 miles on them. I will run the Jet programmer this morning and see how it runs. Gotta firm up and modify the tranny shift points then my plan is to run it for a few tanks of gas and check mileage. After that, I plan to modify the engine parameters and see where I end up fuel mileage wise.

The van was sitting for a couple weeks...battery was dead and the A/C quit working! ](*,) Good thing it's only supposed to be in the low 90's this week!

[LiftedAWDAstro]

I have put 3 or 4 tanks of fuel through now and my mileage has been right around 15 mpg. Right where it was before. Last tank I installed the engine tune mods while still running regular fuel. I'll update once I fill it up again. Working on the front gear swap now.

[LiftedAWDAstro]

I think I am going to have to open it up again. It has been making a noise above 60 mph and it gets louder the faster I go. I know it's not a u-joint as I had those replaced and the shaft balanced already. I also get gear whine when coasting with light throttle. Who knows. maybe I damaged a bearing during install. More to come.

[LiftedAWDAstro]

Opened it up today and found I had no metal particles...that was great! I also found there was about 13 thou of backlash. I also found the carrier preload was not quite enough and the carrier came out with ease. So I moved an 8 though shim from the right side to the left and came up with 7 thou backlash. Put a new pinion crush sleeve and seal in and torqued that so I had 7-10 inch pounds of preload. I then added a 7 thou shim to each side of the carrier and installed it with a little force. Double checked my pattern and it was spot on. Buttoned it up and ran it on blocks. Got a LOT of noise at about 50 mph. It was echoing throughout the cabin yet I couldn't really hear it outside. (I had Lynne running the throttle while I was looking and listening).

Shut it down and got underneath to check over stuff. I found there is a lot of noise coming from the transfer case when I move the driveshaft up and down at the tailshaft position. Tomorrow I will probably pull the transfer case and open that up. Can't believe it's the rear end. ](*,) I at least need to check the fluid in the t-case.

[H2OJoe]

You're my hero. If I opened up my tcase it'd take the rest of my life to put it back together (without a hand full of parts left over, Gee, now where do those go....?)

[photo_van]

What mfg are the gears?

[LiftedAWDAstro]

The gears are used GM's. Going to do more troubleshooting today.

[LiftedAWDAstro]

Pulled a sample of the t-case fluid and found it was fairly clean and only slightly darker than new. Still a nice blue color to it. Definitely needs changing but nothing too bad. I also decided to put the van on the ground and test drive. Found it is much quieter than before but still has a thumping/rumbling noise above 60 mph. Ran it to 70+ and it wasn't too bad. I am gonna just drive it and see what happens!

[photo_van]

Maybe something in the G80? It would be kicking in with the wheels off the ground?

[LiftedAWDAstro]

Van is still making a noise in the rear end. It's a low frequency rumble that is really noticeable about 55 mph and increases as speed increases. I rotated tires to eliminate them. I have also swapped the transfer case out with a NP233 and when running the van on jack stands in 2WD, the noise gets loud around 50 - 55 mph so I know it's not in the front end. I just ordered new AAM gears from Fleetpride and they should be in early next week. Hopefully I can talk my buddy Darrel (his wife is HunternCruse on here) into helping me with it in his heated garage on Wednesday or Thursday. It would nice to cruise at 73 on the interstate and not be deafened by the rumble.

[sportbud]

A Few Ideas. What you have is a difficult area to resolve until you can accurately determine the area were the noise is and the type of noise. An idea is to see if a repair facility near you has a noise locating tool that has seperate transmitters on different frequencies that can be mounted under vehicle at different locations and by remotely turning on and off can get you in the right area. Maybe rent or buy if possible. This is what I would do. Good luck!
Google this J S Products (steelman) 06600 Stethescope Electronic Chassis Ear
Product #: JSP06600

price: $139.34
or
J S Products (steelman) 97202 Chassis Ear Wireless 4 Sensors
Product #: JSP97202

Your Price: $289.79


Detailed Description:

◦Noises can be transmitted up to 50; from transmitter to receiver allowing Wireless ChassisEAR® to be used on larger vehicles

◦No messy wires to string

◦Hear noises that can not be duplicated in the stall

◦Quickly pin-points source and location of noise

Kit includes four clamp on inductive sensors, allowing technician to perform multiple point tests. Allows technician to listen to gears, bearings and suspension while under load so problems can be more accurately pin pointed. Set includes: 6 AA batteries, 16 AAA batteries, molded case, location identifier note pad, instruction manual and organizer pouch.



Also See:
J S Products (steelman) 06400 Stethoscope Electronic Tracer Ear
J S Products (steelman) 06600 Stethescope Electronic Chassis Ear
J S Products (steelman) 06800 Stethescope Electronic Engine Ear #2
J S Products (steelman) 65001 Stethescope Electronic Engine Ear
J S Products (steelman) 97170 Engine Ear Elite
J S Products (steelman) 97202 Chassis Ear Wireless 4 Sensors
Lisle LIS52500 Mechanic's Stethoscope
Lisle 52700 AUDIO STETHOSCOPE
Lisle 52750 STETHOSCOPE SET
Steelman STE6600 ChassisEar Squeak / Rattle Finder - Multi Mic Stethoscope
Steelman STE6635 Leads with Clamps for 6600
Steelman STE97202

Gear Noise



Gear noise or whine is audible from 32 to 89 km/h (20 to 55 mph) under four driving conditions:


Drive - Acceleration or heavy pull
Road Load - Vehicle driving load or constant speed
Float - Using enough throttle to keep the vehicle from driving the engine, the vehicle slows down gradually but the engine still pulls slightly.
Coast - Throttle is closed and the vehicle is in gear. Gear noise most frequently has periods where the noise is more noticeable, usually 48 to 64 km/h (30 to 40 mph) and 80 to 89 km/h (50 to 55 mph).

[LiftedAWDAstro]

I know it's in the rear end as the noise was not there before the gear swap. I have about 3500 miles on them and the noise really hasn't changed much if at all. Going to open it up next week if my gears come in.

[dunedog]

Crank down on that crush sleeve somemore Dean.......put a longer pipe on the breaker bar

[LiftedAWDAstro]

I would except I have the proper preload on the pinion. I actually bought a beam type inch-pound torque wrench plus there is no play in the pinion at all. The noise doesn't change when I am under load, coasting or let off completely. It just gets quieter the slower I go.

[Smiliesafari]

Sounds like it might be an axle bearing.