Front + rear diff and transfer case service on 24 Tahoe

[redhat]

Thursday with a little over 25k on the 24 Tahoe. Serviced the front and rear differentials along with the transfer case.

First service on these units. Different from the trucks with a solid rear axle, this IRS rear differential has good size drain (at bottom) and fill plugs on the case. Fluid looked very clean. Hardly any metal on the magnet of the drain plug. Out went the OE 75W-85. Refilled with AMSOIL Severe Gear 75W-90.

Transfer case is your usual GM auto high/low case. Fluid was also pretty clean with some normal metal sludge on the drain plug magnet. Out went the OE Dex VI. Refilled with AMSOIL Signature Series LV ATF.

Front differential, GM deleted the drain plug on these newer IRS front units. I used a fluid extractor to suck the fluid through the fill hole. The fluid was pretty grey looking with some metal. Refilled again with AMSOIL 75W-90. I know AFE and PML are working on replacement covers for these with drains. I am thinking a cover with a drain (plus magnet in the drain) would help this fluid remain cleaner.

Also was due for an oil change and went with AMSOIL Signature Series 0W-40 and a Delco UPF63R filter.

I am happy I have serviced them by now. Pleased with the conditions of the rear and transfer case. Hoping the front will clean up some along with an eventual magneted drain plug. I have to assume this is it either breaking in or usual GM front looking bad?

 

[Lubener]

A good plan. You did more than most people do when they never change out those fluids for the life of the vehicle.

 

[PontiacHO]

You’re set of years of trouble free use now.

 

[Donald]

I need to order some Amsoil gear oil and ATF.

I have tried the soft QT container Amsoil sells the gear oil in. But seems difficult to recap an opened one. Had half a QT of gear oil spill into my storage container for various oils. A mess.

 

[Dino01]

Fronts looking bad on the initial fill, even at low mileage seems to be the norm in my experience, for whatever reason, especially on Toyotas

 

[redhat]

I need to order some Amsoil gear oil and ATF.

I have tried the soft QT container Amsoil sells the gear oil in. But seems difficult to recap an opened one. Had half a QT of gear oil spill into my storage container for various oils. A mess.

You’re right the cap seems like it could seep some. The LV ATF is cheaper in quart bottles vs the easy pack. So I’ll prob keep one or maybe two easy pack packages empty as they were super handy for the transfer case and refill if needed. Severe gear was no cheaper by the quart.

Front and rear diffs I used a pneumatic fluid pump. There’s hardly room otherwise.

 

[redhat]

A good plan. You did more than most people do when they never change out those fluids for the life of the vehicle.

I definitely want to try my best to keep this thing nice.

 

[4wd]

Thursday with a little over 25k on the 24 Tahoe. Serviced the front and rear differentials along with the transfer case.

First service on these units. Different from the trucks with a solid rear axle, this IRS rear differential has good size drain (at bottom) and fill plugs on the case. Fluid looked very clean. Hardly any metal on the magnet of the drain plug. Out went the OE 75W-85. Refilled with AMSOIL Severe Gear 75W-90.

Transfer case is your usual GM auto high/low case. Fluid was also pretty clean with some normal metal sludge on the drain plug magnet. Out went the OE Dex VI. Refilled with AMSOIL Signature Series LV ATF.

Front differential, GM deleted the drain plug on these newer IRS front units. I used a fluid extractor to suck the fluid through the fill hole. The fluid was pretty grey looking with some metal. Refilled again with AMSOIL 75W-90. I know AFE and PML are working on replacement covers for these with drains. I am thinking a cover with a drain (plus magnet in the drain) would help this fluid remain cleaner.

Also was due for an oil change and went with AMSOIL Signature Series 0W-40 and a Delco UPF63R filter.

I am happy I have serviced them by now. Pleased with the conditions of the rear and transfer case. Hoping the front will clean up some along with an eventual magneted drain plug. I have to assume this is it either breaking in or usual GM front looking bad?

I believe the other thing that’s different is these are more like a positrac than before - and sensitive to FM. I took my ‘22 out to an empty parking lot and did figure 8’s after 2 bottles of AC DELCO FM. It had a howl on left turns. 3rd bottle and done.
The ASG might have more LSD FM than my Delvac 1 - but I’d still do some windows down testing …

 

[redhat]

I believe the other thing that’s different is these are more like a positrac than before - and sensitive to FM. I took my ‘22 out to an empty parking lot and did figure 8’s after 2 bottles of AC DELCO FM. It had a howl on left turns. 3rd bottle and done.
The ASG might have more LSD FM than my Delvac 1 - but I’d still do some windows down testing …

Good advice, thanks. Will have to check this out… when the snow stops! Now I was under the impression Delvac never had any FM or LS additive compared to Mobil 1 gear oils of the same viscosity?