GM 75w-90 Synth, As good as other synth gear oils?

Messages
4,009
Location
Calgary Canada
I need this GM 75w-90 Synth for my pickup and have a chance to buy some at a good price ($8.00/L - which is really good around here). Nothing around here (other synthetic gear lube brands) is competitive in terms of price. I'm thinking of buying some extra for my BMW (car and motorycle final drive) and am wondering if this is decent stuff that people would use in products other than GM (for the purposes of protecting warranty). IIRC, I have read that this is a very good gear oil, but the only downside is that it's over priced. Any thoughts would be appreciated.
 
Messages
6,917
Location
NH
Decent gear oil but nothing special about it. Way over priced from a dealer. I always replaced it in my Silverado's with RP MaxGear. If you feel $8L is a good price then go for it. It isn't a bad gear oil but again nothing special seems to be the popular opinion.
 
Messages
2,912
Location
MI, USA
 Originally Posted By: Jim 5
No Mike, I think it's the grape stuff PT1 refers to.
What Mike is referring to is the new product. DEXRON-LS 75W-90. I think that the Goodwrench part number is 88862624 but I believe that it is also available from other sources. Advantages are, improved oxidation, improved (and durable NVH), improved low temperature performance, and possibly better fuel economy compared to the earlier fluid.
 
Messages
12
Location
California
In my case I changed out the factory fill stuff at 15,000 miles in the Sierra 2500HD (DuraMax 4X4) because the dealer refused, saying it was a waste of money. Good thing too, because the OEM stuff looked like the coolant oil from my old DO-All band saw. Refilled with Amsoil 75W-90 Severe Gear in both differentials, the product does not need any additive for the Eaton 80 locker. I feel a bit more secure with Amsoil when going to an extended drain interval. When I used regular limited slip gear oil in another GM truck that towed a travel trailer, I would drain and refill annually. That seems to be the charm, that truck is still running with 33 years on the original axle and carrier bearings. Maybe it isn't the lube but keeping it clean that's the trick.
 
Last edited:
Messages
598
Location
UT, USA
 Originally Posted By: axlenut
In my case I changed out the factory fill stuff at 15,000 miles in the Sierra 2500HD (DuraMax 4X4) because the dealer refused, saying it was a waste of money. Good thing too, because the OEM stuff looked like the coolant oil from my old DO-All band saw. Refilled with Amsoil 75W-90 Severe Gear in both differentials, the product does not need any additive for the Eaton 80 locker. I feel a bit more secure with Amsoil when going to an extended drain interval. When I used regular limited slip gear oil in another GM truck that towed a travel trailer, I would drain and refill annually. That seems to be the charm, that truck is still running with 33 years on the original axle and carrier bearings. Maybe it isn't the lube but keeping it clean that's the trick.
I just had my mechanic pull the diff cover and replace the fluid in our 08 Savanna van at 10k. I'm hoping he didn't shaft me, and pocket the amsoil and put in cheap stuff. My first suspicion is the fact the van has lost about 1.5-2 mpg since the switch. Did you notice any MPG drop after putting the amsoil in?
 
Messages
2,262
Location
SD
 Originally Posted By: 3Toyotas
I just had my mechanic pull the diff cover and replace the fluid in our 08 Savanna van at 10k. I'm hoping he didn't shaft me, and pocket the amsoil and put in cheap stuff. My first suspicion is the fact the van has lost about 1.5-2 mpg since the switch. Did you notice any MPG drop after putting the amsoil in?
I would look for other causes. Even if he did put in a cheaper gear oil, I have a hard time believing it would cause that much mpg drop.
 
Messages
6,917
Location
NH
 Originally Posted By: zrxkawboy
 Originally Posted By: 3Toyotas
I just had my mechanic pull the diff cover and replace the fluid in our 08 Savanna van at 10k. I'm hoping he didn't shaft me, and pocket the amsoil and put in cheap stuff. My first suspicion is the fact the van has lost about 1.5-2 mpg since the switch. Did you notice any MPG drop after putting the amsoil in?
I would look for other causes. Even if he did put in a cheaper gear oil, I have a hard time believing it would cause that much mpg drop.
I wouldn't doubt it if the FF was dino gear oil. Swapping dino over to synthetic gear oils can have huge benefits in the MPG dept. 3Toyotas I would be very suspiscious as well. Not sure what you can do to check but I would definitely be sure to watch them change it in the future.
 
Last edited:
Messages
1,565
Location
Elkridge, MD
If the P/N for the gear oil is, in fact, 88862624 as suggested above, I'd say that's a pretty good price. Considering its $13.21 a liter from gmpartsdirect.com, and you've gotta buy it in at least a 12 pack, and that doesn't include shipping, $8 seems like a steal.
 

Jim 5

Thread starter
Messages
4,009
Location
Calgary Canada
 Originally Posted By: live_to_hunt
I put Amsoil Sever Gear in My 03 Silverado.. So far so good. The grape fluid was $28 a qt the Amsoil was half that so I bought Amsoil
Can't remember seeing a deal this good. Dealership was having a blow out - I picked up : - 6L of the synthetic gear oil for $7 each - 2L of the autotrak II transfer case oil for $4.50 each - 4 oil filters for $4.50 each - 4 Spin on transmission filters for $8.00 each This might not seem like a good deal for america, but in Canada, this is at least 50% off and in some cases 2/3rds off.
 
Messages
3,023
Location
USA-Michigan
I read a while back in a GM bulletin that mentioned Texaco (same source for Dexcool) was the supplier of the synthetic gear lubes. Don't know if this is still current or not.
 
Messages
6,917
Location
NH
 Originally Posted By: Jim 5
Can't remember seeing a deal this good. Dealership was having a blow out - I picked up : - 6L of the synthetic gear oil for $7 each - 2L of the autotrak II transfer case oil for $4.50 each - 4 oil filters for $4.50 each - 4 Spin on transmission filters for $8.00 each This might not seem like a good deal for america, but in Canada, this is at least 50% off and in some cases 2/3rds off.
Not sure on the currency exchange or if you already converted to US Dollar prices? However, I am going to say the prices, regardless of Canadian/US, on the fluids are excellent considering what they run at the dealer normally. The synthetic gear oil runs $25-$30+ here and the Autotrak II fluid runs $20-$25+ a bottle. I am not sure on the tranny filter cost? The oil filter price, in US Dollars, is actually about what we pay aftermarket for most AC filters. Maybe even a little more.
 
Last edited:

Jim 5

Thread starter
Messages
4,009
Location
Calgary Canada
I'm talking Canadian Dollars, so you can reduce that price by another 20% or so. We usually pay around $10 per oil filter and about $20 for the spin on trans filter. The synthetic gear oil usually runs close to $30 and Mobil 1 synth retails for around $18. Not sure about the autotrac II, but as it turns out, that's not the fluid for my transfer case after all. Looks like its Dex VI.
 
Messages
6,917
Location
NH
The Autotrak II fluid was for the electronic( ie; dash control to shift )t-case. 1/2 tons only I believe.
 
Last edited:
Messages
228
Location
Happy Valley, PA
 Originally Posted By: NHHEMI
The Autotrak II fluid was for the electronic( ie; dash control to shift )t-case. 1/2 tons only I believe.
Per my GM dealer the autotrak II fluid is for transfer cases that switch automatically between 2 and 4 wheel drive (button labeled AUTO) not the electric shift models in 2500 HD pickups
 
Top