Hi,

Hope some one can help me with this ? I want to change tranny fluid in my 05 Bonneville (3.8L V-6) My owners manual calls for Dexron lll and "approved for H - specification". The only fluid I can find that mentiones "H specification" is an Amzoil synthetic that is the equvilant of Dexron V or Vl (can't remember for sure). Anyway, my under standing is the Dexron lll is still a petroleum product and I should not change over to synthetic at this time ? My Bonny has 134,000 miles on it.

When I was looking at the different fluids at Nappa, the guy had me bring in the dip stick to look at the stamped info on it. Come to find out, the dip stick is not the original. I bought this car with 40,000 miles on it and some where along the line the dip stick got mixed up with some one elses or had to be replaced for what ever reason ?.

I had the fluid changed at 50,000 and 90,000 but niether of my reciepts mentions specifically what flulid was used.

Any help out there ? Thanks !

Dexron VI is backwards compatible with Dexron everything-else-before.

I don't believe DexIII is made any more.

I have found Dex lll by various manufactures but the "specification H " is no where to be found ?

If you found Dex III anywhere you probably shouldn't buy it. GM hasn't issued licensing for Dex III in at least 5 years. They've only issued new licenses for Dex VI since its introduction, all the companies making the Dex fluids have to make their own interpretation of Dex VI to tight specs to be rewarded a license. VI was designed to be compatible with the Dex specifications before, and in some cases exceed them (since its a synthetic).

Where did I see all of this? Try Bob is the Oil Guy'* forum.

Walmart has Pennzoil and Castrol trans fluids for Dex/Mer. They specifically state on the back they are for Dexron III vehicles: 2005 and prior. They have similar exemptions for Fords to make clear which ones the fluid is correct to use as service.

I believe it was about $3.69 per quart. I bought 6 to use to service my 2003 trans again with a pan drop and filter.

That dex/merc stuff makes me feel like its a jack of all trades master of nothing type of thing. I shelled out 6 dollars a quart for Wolf'* head Dex VI at a smaller auto parts store (they only had dex/merc at Autozone and such, and a store brand Dex at Walmart). I just found out that Advanced auto parts sells Dexron VI for 3.29 a quart on sale (there are none in NYC), you might want to look there if you get a chance. Our trannies are sorta delicate, so I think its better to get the best formula they have for em.

I would use anything that said Dex III. You will not have a problem. You could always add a bottle of red or platinum Lubeguard to it.