Eaton G80 problem

Thanks for the replies.I haven't worked on it yet, but after consulting with my brother in law decided we decided to get the brake lines without the gravel guard since the truck won't be driven much. I ordered a set of stainless steel lines from inline tube that are made in USA. I am fixing that before working on the differential.

I changed the gear oil in mine after the first 600 miles of towing and again when I put on a better diff cover.

I am using Mobil 1 synthetic gear oil 75x90. Look for a GL5 rating on the bottle to make sure the ring & pinion, seals & bearings are protected. Limited slip additive is not needed.

GM grape juice just has a big dealer markup on it and the grape smell.

Can't help on the brake lines - may try this http://dmaxstore.com or http://merchant-automotive.com

Yes, look for this stuff (The improved grape scent through me off LOL)

If you cannot find protected brake line, you can run split fuel line over the areas that will see the most debris kick up. Run the split to the bottom to allow any water to easily drain instead of pooling.

Thunderbolt wrote:
I am working on my brothers Silverado.....;One other question. I am replacing brake lines too. Most kits I find don't have the gravel guards on the lines. Will this be ok ?

I replaced all the lines on my old '04 2500HD this summer. The AC Delco kit I got from Carquest had all the lines coated in vinyl. I think I paid about $90 for the complete kit.

KJ

Lessmore wrote:
I had a G80 Locking axle. The important thing is when you do replace the gear oil, make sure it's the proper stuff as recommended by GM. When I first got it, I assumed it was a posi or a positraction limited slip.

I wanted to use gear oil for a posi, until the Chevy service manager corrected me. He told me that the truck line uses a G 80 Locker, the car line (back in the RWD days) uses a posi Limited slip....and there is specific and different gear oil for each.

exactly. GM makes a specific gear oil for the G80 diff, commonly refered to as "grape juice". Actually what it kinda smells like when you open a bottle. IIRC the G80 takes about 4 quarts.

Entirely different from the gear oil for a posi unit or open differential.

on both my duramax's with the G80 I drained and filled after about 1K miles (what GM used to recomend), then about every 50K miles.

I had a G80 Locking axle. The important thing is when you do replace the gear oil, make sure it's the proper stuff as recommended by GM. When I first got it, I assumed it was a posi or a positraction limited slip.

I wanted to use gear oil for a posi, until the Chevy service manager corrected me. He told me that the truck line uses a G 80 Locker, the car line (back in the RWD days) uses a posi Limited slip....and there is specific and different gear oil for each.

if the lube hasn't been drained/filled in the last 100K miles or so I'd first try draining and filling with the GM "grape juice" that the G80 has as a factory fill. see if that helps.

This is what I found on the net, years ago you use to add the additive..

LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION) #91-4-109
SUBJECT: LOCKING DIFFERENTIAL (G80) LUBRICANT - (SERVICE INFORMATION)
VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS
Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.
This condition of alternate engagement and disengagement of clutches in differential assembly is usually caused by contaminated axle lubricant.
To correct this condition, drain and refill the rear axle with SAE 80W-90 GL5 (P/N 10950849).

The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.

VEHICLES/COMPONENTS INVOLVED: ------------------------- ---- Some light duty trucks equipped with locking rear axles, RPO G80.
SERVICE PARTS INFORMATION:
Part Number Description ----------- ------------------ 10950849 Lubricant, Rear Axle (1 litre)
Parts are currently available through CANSPO.
WARRANTY INFORMATION:
As specified in Light Duty Truck Maintenance Schedules, locking rear axle fluid drain and refill is required owner maintenance at the first engine oil change. Failure to drain and refill the rear axle as specified may contribute to a later axle chatter condition. Refer to the appropriate Light Duty Truck Maintenance Schedule or service manual, section OB, for further details on change intervals.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
© Copyright General Motors Corporation. All Rights Reserved.

On the brake lines I would check with "classic tube". I think most of there lines are factory correct so they should include the gravel guard the same as original.