Conventional 5W-30 No Longer Available?

[L31MaxExpress]

Good point, and a good reason to stick to the recommended GM fluids IMO.

Problem with the Dex VI is it is low viscosity garbage. Our transmissions were not designed to use it. My transmission builder friend is seeing all kinds of bushing/needle bearing failures that damage hard parts in transmissions running Dex VI. GM has a TSB that supercedes earlier fliuds to DexVI. GM is in the business to build and sell new vehicles, not keep 20-25 year old vehicles on the road another 10 years. I'll stay with Dex III equivalent, I use Valvoline myself.

Using Dex VI in these well worn transmissions is equivalent to putting 0w16 in the engine and hoping for the best. Some may get away with it, but some are going to fail.

Nearly 20 years ago Nissan tried the same low viscosity junk in their 5spd FWD transmissions to eek out better CAFE mileage. Maxima, Altima and Quest all had a rash of 5spd transmission failures, before the CVTs were introduced. Basically any transmission that used Matic-K low viscosity fluid was failing.

 

[Pinger]

Nearly 20 years ago Nissan tried the same low viscosity junk in their 5spd FWD transmissions to eek out better CAFE mileage. Maxima, Altima and Quest all had a rash of 5spd transmission failures, before the CVTs were introduced. Basically any transmission that used Matic-K low viscosity fluid was failing.

Is that standard ATF fluid (with much lower viscosity that normal gear oils) you are referring to? That's been common for a while here (UK). Ford specified in manual gearboxes and as far as I know was trouble-free. My smart used it too - but with it (and possibly others) at least some of the bearings were sealed units with, presumably, grease in them.
Do you know if the Nissan failures were bearings or gears?

 

[0xDEADBEEF]

Problem with the Dex VI is it is low viscosity garbage. Our transmissions were not designed to use it. My transmission builder friend is seeing all kinds of bushing/needle bearing failures that damage hard parts in transmissions running Dex VI. GM has a TSB that supercedes earlier fliuds to DexVI. GM is in the business to build and sell new vehicles, not keep 20-25 year old vehicles on the road another 10 years. I'll stay with Dex III equivalent, I use Valvoline myself.

Using Dex VI in these well worn transmissions is equivalent to putting 0w16 in the engine and hoping for the best. Some may get away with it, but some are going to fail.

Nearly 20 years ago Nissan tried the same low viscosity junk in their 5spd FWD transmissions to eek out better CAFE mileage. Maxima, Altima and Quest all had a rash of 5spd transmission failures, before the CVTs were introduced. Basically any transmission that used Matic-K low viscosity fluid was failing.

GM set up a lot of transmissions to fail by saying you could use DexVI wherever DexIII was called for. Track buddy killed his T56 from that.

 

[L31MaxExpress]

Is that standard ATF fluid (with much lower viscosity that normal gear oils) you are referring to? That's been common for a while here (UK). Ford specified in manual gearboxes and as far as I know was trouble-free. My smart used it too - but with it (and possibly others) at least some of the bearings were sealed units with, presumably, grease in them.
Do you know if the Nissan failures were bearings or gears?

The 5spd I mention is an automatic. Matic-K is an ATF with a much lower viscosity than the previous Matic-D (DexIII) They all had metal shavings in the pan and screen when they failed. We pulled the pan, confirmed metal in the pan, then pulled the units complete and installed a reman unit. Whatever was failing caused low line pressure, took out the lockup and would often cause a delayed engagement. Like have to rev the car up to 1,500-2,000 rpm before the clutches would grab.

 

[AuroraGirl]

Problem with the Dex VI is it is low viscosity garbage. Our transmissions were not designed to use it. My transmission builder friend is seeing all kinds of bushing/needle bearing failures that damage hard parts in transmissions running Dex VI. GM has a TSB that supercedes earlier fliuds to DexVI. GM is in the business to build and sell new vehicles, not keep 20-25 year old vehicles on the road another 10 years. I'll stay with Dex III equivalent, I use Valvoline myself.

Using Dex VI in these well worn transmissions is equivalent to putting 0w16 in the engine and hoping for the best. Some may get away with it, but some are going to fail.

Nearly 20 years ago Nissan tried the same low viscosity junk in their 5spd FWD transmissions to eek out better CAFE mileage. Maxima, Altima and Quest all had a rash of 5spd transmission failures, before the CVTs were introduced. Basically any transmission that used Matic-K low viscosity fluid was failing.

DEX VI has a HIGHER VISCOSITY than Dex 3 at operating temp. Your anger is understandable but its just wrong.
Also if you didnt read, Dex III can be bought from GM, but anything labeled Dex 3 for sale is in no way been tested or verified to be such so you are trusting an random aftermarket more than GM (who was still honoring warranties btw in vehicles which came with Dex III)
75-90 or 75-80 is Dex III , but their viscosity is not measured the same way as engine oil

Also, fun fact, GM has calculated the amount of skin exposure of dex 3 it takes to kill a rabbit. That is all.

 

[AuroraGirl]

GM set up a lot of transmissions to fail by saying you could use DexVI wherever DexIII was called for. Track buddy killed his T56 from that.

Your track buddy killed a T56 transmission, which specifically is not supposed to use Dex VI, when he used Dex VI. SHOCK. GM told everyone with their TSB to use GM Manual Transmission and Transfer Case Fluid after Dex VI replaced Dex III

 

[0xDEADBEEF]

Your track buddy killed a T56 transmission, which specifically is not supposed to use Dex VI, when he used Dex VI. SHOCK. GM told everyone with their TSB to use GM Manual Transmission and Transfer Case Fluid after Dex VI replaced Dex III

Even worse, the dealership did it.

 

[HotWheelsBurban]

So where does one obtain proper Dexron lll? Now you've got me concerned that I put the wrong stuff in my trucks, topping them off....

 

[L31MaxExpress]

DEX VI has a HIGHER VISCOSITY than Dex 3 at operating temp. Your anger is understandable but its just wrong.
Also if you didnt read, Dex III can be bought from GM, but anything labeled Dex 3 for sale is in no way been tested or verified to be such so you are trusting an random aftermarket more than GM (who was still honoring warranties btw in vehicles which came with Dex III)
75-90 or 75-80 is Dex III , but their viscosity is not measured the same way as engine oil

Also, fun fact, GM has calculated the amount of skin exposure of dex 3 it takes to kill a rabbit. That is all.

I DO trust the aftermarket more than I trust GM.

 

[df2x4]

So where does one obtain proper Dexron lll? Now you've got me concerned that I put the wrong stuff in my trucks, topping them off....

Kind of depends on your definition of "proper" unfortunately. If you mean produced and/or licensed by GM, it doesn't exist. I would imagine that most of the big names still selling Dexron 3 "compatible" fluids are probably fine, but as AuroraGirl mentioned there's really no reasonable way to be sure that any of them match the original GM specifications.