Mixing conventional & synth ATFs?

[Benzadmiral]

Any BITOGer knows about the old myth of not mixing conventional and synthetic oils. And I thought it applied to ATFs as well. But my regular mechanic is skeptical about changing from the standard Dexron I've been using for some 60K miles (with a drain and filter change every 30K). I asked about going to Maxlife ATF or another synthetic. His reply: "Mixing oils, sure, but ATF, I'm leery of that."

So my question is 2-part:

1) Is there any point in changing to a synth at this point in my car's life? The Buick has 110K miles, and the transmission has been fine. (That is, except for the recurring issue of the very hard shifts, both while accelerating and decelerating, that crop up intermittently, usually when I'm driving in stop-and-go traffic, and which go away once I stop the car and restart. I wonder if a different ATF might help with that? The issue began before the 80K mile change and has continued after it.)

2) Is there any problem for the transmission with changing from conventional to synthetic?

 

[simple_gifts]

Considering most people get < 50% of fluid out during a D+F any issues with mixing would have surfaced a long time ago. I put 4-5qts of Maxlife in my friends Tundra (12+qts) and she instantly noticed the difference.

With all the good reports re: maxlife, don't talk yourself out of it. JMO.

 

[901Memphis]

Mixing is fine and actually recommended by many for something Ford applications.

The Maxlife is a fine product and should give you a longer service life than mineral based dex/merc.

The hard shift problem is well documented if you have a 4T65e like me. It doesn't go away on its own you need a transgo kit installed to relieve it.

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1998882

 

[SuperDave456]

I've done it several times.

2004 Nissan Xterra, 1998 Ford F150, 2001 Ford Taurus, 2002 Ford Taurus... those are the ones that come to my mind right now.

They all still have good transmissions. My sister did too many 15,000 miles OCI's on the 2001 Taurus and somehow killed it, although it still had a good transmission at the time of death.

I do a drain and fill almost every year on something.
I find a fluid that meets that spec, usually Maxlife, and use it and a bottle of Lubeguard Red. I've never had an issue doing it that way.

 

[901Memphis]

Double post removed.

 

[oilmaven]

All of the ATF bottles I've seen have a statement to the effect that the product is compatible with ALL trans fluids (be it conventional, blend or full syn). My 'ol villager just had it's second drain and fill with Redline D4...original owner did one service with conventional Mercon. I noticed a definite improvement in cold shifting after the first change (which got me about a 40% synthetic blend). Except in the case of fluid-specific vehicles (Honda and Chrysler come to mind) I don't think mixing fluids is a problem.

 

[tommygunn]

There is no problem with this.

In fact, the Dexron-VI that has been back-spec'd is a synthetic blend, although full-syn D6's do exist. In fact, it may help with your hard shifts due to being thinner.

Synthetic ATF's don't cost that much more than regular and are changed far less often than motor oil.

I hope the mechanic does regular drain-and-fill and not power flushing your transmission!

 

[Benzadmiral]

Originally Posted By: tommygunn
. . . I hope the mechanic does regular drain-and-fill and not power flushing your transmission!

Well, I've had the trans drained and refilled twice in the 60K miles I've owned the car. I'm reasonably sure he does the regular drain-and-fill, along with replacing the filter.

I'll print out the info on the Transgo shift kit that 901Memphis linked to, and show it to my mechanic. He's kind of old-school on some things, but he saves you money and keeps your car running well. If he'll do the kit installation at the same time as putting in some Maxlife ATF, and it works, it'll be a tremendous bargain.

 

[901Memphis]

If you can get the mechanic to install the transgo kit, you have a keeper!

 

[SwedishRider]

I recently had a drain and fill done on my Ford Ranger with Amsoil ATF and a Wix filter, and it is shifting much, much better. Previously, I had a flush done with Mercon V, but from now on I think I am going the route of D&F with Amsoil and a filter. Mixing fluids had a beneficial effect in my case.

 

[Benzadmiral]

Originally Posted By: 901Memphis
If you can get the mechanic to install the transgo kit, you have a keeper!

Oh, trust me, I'm gonna "keep" him (or did you mean the car?). Just in case, though, I'm going to try and locate a good transmission shop. Cottman, I suppose, is a possibility, and there's a small shop in Mid-City whose ads say they've been there 30 years.

 

[Whitewolf]

Originally Posted By: tommygunn
There is no problem with this.

In fact, the Dexron-VI that has been back-spec'd is a synthetic blend, although full-syn D6's do exist. In fact, it may help with your hard shifts due to being thinner.

Synthetic ATF's don't cost that much more than regular and are changed far less often than motor oil.

I hope the mechanic does regular drain-and-fill and not power flushing your transmission!

Just in case that you didn't know, you are wrong. Most of the world defines synthetic as exactly that, apart from the USA. The vast majority of DEXRON-VI fluids are group III. It is correct that there are some true synthetic DEXRON-VI fluids but they are rare and hard to find.

 

[artificialist]

I never had any problems draining out some conventional and filling with some syn, so long as the fluid met the correct specs.

 

[The Critic]

Originally Posted By: Whitewolf
Originally Posted By: tommygunn
There is no problem with this.

In fact, the Dexron-VI that has been back-spec'd is a synthetic blend, although full-syn D6's do exist. In fact, it may help with your hard shifts due to being thinner.

Synthetic ATF's don't cost that much more than regular and are changed far less often than motor oil.

I hope the mechanic does regular drain-and-fill and not power flushing your transmission!

Just in case that you didn't know, you are wrong. Most of the world defines synthetic as exactly that, apart from the USA. The vast majority of DEXRON-VI fluids are group III. It is correct that there are some true synthetic DEXRON-VI fluids but they are rare and hard to find.


When Whitewolf talks, I pay attention.

 

[901Memphis]

Which is a good reason to use Maxlife.