Front Diff or Transfer Case

[Wylie_Tahoe]

03 4x4 Z71 5.3 flex.

Anyone have a front diff assembly or transfer case from a donor that might be collecting dust? Not sure yet which im gonna need but one of them let go today. Figured id start with the community before searching salvage yards.

 

[Mudsport96]

Sooo what is going on with your rig? Maybe we can help troubleshoot.

 

[Wylie_Tahoe]

Somtin blew. It made a chit load of noise and shudder, as a came to a stop. Would still move forward, but not reverse. Made a very load whirring sound when moving. Will be Wednesday at the earliest before I can get it moved into my shop and on jack stands.

Just getting the feelers out there to see what might be laying around.

 

[TJ Baker]

Do remember if replacing the front differential you need to match your existing gear ratio.

 

[rockola1971]

car-parts.com for a Tcase core if yours is grenaded or a front diff. They are stupid easy to rebuild. Visually inspect Tcase to see if chain decided to come out and see you.

 

[OR VietVet]

No reverse? Transmission?

 

[Wylie_Tahoe]

Cant figure out the front diff's RPO. Any guesses on what let it would start with? Of what front diff RPO's an 03 Z71 4x4 would have possibly come with?

I do know this rig has a donor rear diff, so I do need to confirm its ratio matches the RPO.

 

[S33k3r]

As far as I know, there isn't a good, external means of determining axle ratio. Best bet is to put it on stands, rotate the wheels, and see how much the wheels turn in comparison with the drive shaft.

 

[Mudsport96]

Cant figure out the front diff's RPO. Any guesses on what let it would start with? Of what front diff RPO's an 03 Z71 4x4 would have possibly come with?

I do know this rig has a donor rear diff, so I do need to confirm its ratio matches the RPO.

Would be the same as the (original)rear if it wasnt changedto match the donor. Gu6 is 3.42, gt4 is 3.73. Post the G codes and we can go from there. Even better would be a pic of the rpo sticker.
As for the noise going forward and no reverse, that sounds like a bad sunshell in the transmission

 

[Wylie_Tahoe]

No reverse? Transmission?

Good question, but there is definitely output shaft rotation when shifted into reverse as well as forward. She makes all kings of noise in gear, but purrs like a kitten when in park.

 

[Wylie_Tahoe]

I know the front ratio will be the same as the rear, just wanted to make sure there was not a differential type RPO to insure I source the correct front diff. There are 2 RPOs for the rear. One is the ration and other denotes if its a peg leg or limited.

 

[Mudsport96]

I know the front ratio will be the same as the rear, just wanted to make sure there was not a differential type RPO to insure I source the correct front diff. There are 2 RPOs for the rear. One is the ration and other denotes if its a peg leg or limited.

About the only way you can know for to front diff to be sure, will be to put it in 4wd to lock in the pass side axle and roll the vehicle forward or backwards one tire rotation and count how many times the driveshaft turns. I usually tape a piece of string to the 6 o'clock position of the driveshaft and count how many times it wraps around. 3 times would ne close to a 3 08, a three and a half would likely be a 3.42 and above that would be 3.73

 

[Wylie_Tahoe]

Update;

Ive had some time on and off the past week to work on the rig. The noise is in the area of the trans tail shaft and input stage of the transfer case. Pulled the t/case and no noise or abnormal feel when turning the t/case shaft by hand.

Put the trans mount and crossmember back in and fired up the engine. Sadly, the noise is still present. So, its in the transmission.

Anyone interested in a project/donor/parts truck?