Help 05 GXP tranny not engaging

[CMNTMXR57]

About the only thing I would recommend is keeping your fluid/filter clean and changed regularly. I know you posted somewhere that yours has >80k on the odometer. I would hesitate to do a power flushing at this time as you may actually dislodge some debris that'll cause more problems down the road.

Otherwise, the only way to "Beef" one up, is to remove it and send it to a shop that specializes in building HD/race transmissions. There is nothing you can do, or nothing you can service on the unit yourself that will increase it's durability.

[1fatcat]

Well, you could add a cooler and toss in a bottle of Lube Guard. That should help increase durability.

[Bigerik]

About the only thing I would recommend is keeping your fluid/filter clean and changed regularly. I know you posted somewhere that yours has >80k on the odometer. I would hesitate to do a power flushing at this time as you may actually dislodge some debris that'll cause more problems down the road.

Otherwise, the only way to "Beef" one up, is to remove it and send it to a shop that specializes in building HD/race transmissions. There is nothing you can do, or nothing you can service on the unit yourself that will increase it's durability.

I'm due for a pan drop. No interest in doing a flush. Never know what happens then. No replacable filter in the 4T80, if I remember correctly.

I didn't mean anything I could do myself. More a matter of what can be done. I know there is some stuff available for the 4T65, but even things there are limited.

My transmission shop is one of the finest in Canada, and specialize in doing all the 4T65's for the Grand Prix crowd.

[CMNTMXR57]

Both the 4T65E and 4T80E have an integral transmission cooler in the radiator. Granted it was an option on some vehicles with the 4T65, but I’m pretty sure it’s standard issue on a 4T80. Adding an external one (whether in tandum or as a replacement for the OEM, capping off the OEM plumbing and running it to the external cooler) probably won’t add much or minimal affect if any to the cooling of the fluid for the time and money spent. The only benefit for the time and money invested, would be if you didn’t have one in the first place.

As to the additive. People live in the world where they think that adding to your main “fluids” (I.E. Oil, gear lube, trans fluid, coolant, etc) is a good thing. In most cases, you’re probably “ok” with doing it. Engine oil is really only called upon to lubricate and cool. Cooling system the same, Gear lube is meant to lubricate, cushion, and to some extent cool. However transmission fluid is kind of an oddball. It’s not only meant to lubricate and cool, but also used to build hydraulic pressure. The pressure is important and vital to the adequate running of the entire unit from the pump, through the valve body, solenoids, actuators, cooler, then back to the pan. The electronics (I.E. Solenoids and actuators) rely on said pressures too. While the PCM controls their function, proper pressures through the system is also required for them to work efficiently.

With this said, adding an additive can alter the properties (both lubricity, and viscosity) of the overall fluid, which in turn can alter how the fluid works, more importantly, the pressure(s) built by the pump. GM specifically asks for Dex III on ours. They may specify Dex 4 in others. They do this for a reason. While we can question their engineering on other areas of the car (as they have to make it fit a wide variety of consumer needs), one area their engineer’s, with multitudes of PhD’s, who spend countless hours doing R&D DON’T skimp on, is the fluids they specify for their engines, transmissions, and drivetrain. They specify D3 for our transmissions because it meets their requirements for lubricity, cooling, and hydraulic pressure capabilities. If they felt it wasn’t sufficient, they’d have recommended an additive from the start.

Mind you, I’m not saying Dura-Lube, or any other additive is bad on it’s own merit, just stating that I’m very hesitant, and generally don’t recommend adding an additive to the transmission fluid. I’m fine with other areas as I do add additives myself (I’m a fan of Lucas products), but on the trans, nope!

[CMNTMXR57]

Erik, there is a main filter, it's kinda like a long rectangle. Then there is both a left and right scavenger filter.

[00Beast]

Lane, while all that you said is true, I do somewhat disagree on the cooler. The problem with a cooler in the radiator is that it puts the transmission fluid right next to 190°+ coolant. I don't want/need my trans at 190°, 160° is plenty warm. That is where an auxiliary cooler that is separate helps keep the fluid at optimal temperature for that fluid.

[1fatcat]

If you guys want to talk about longevity, ask why police cruisers are only shut off at the end of the shift. The process of "heat soak" is the REAL toll on cars (assuming it's maintained).

CMNTMXR57, I disagree with some of what you say, but not all of it.

[CMNTMXR57]

Lane, while all that you said is true, I do somewhat disagree on the cooler. The problem with a cooler in the radiator is that it puts the transmission fluid right next to 190°+ coolant. I don't want/need my trans at 190°, 160° is plenty warm. That is where an auxiliary cooler that is separate helps keep the fluid at optimal temperature for that fluid.

This covers both Ed's and FatCat:
Newsflash: 160* trans fluid temp is considered borderline too cold! NORMAL OPERATING TEMPERATURE for most automatic transmissions/transaxles is in the 175* to 190* range. Anything above 210* and you start losing pressure. 230* and valves in the valve body may start sticking. At about 250* the fluid will start to varnish. From about 270* and up, seals and clutches burn. Push over 300* and transmission failure is imminent. Just for example, DexronIII has a "flash point" of about 390*, and "fire point" of 400*. With this in mind, running your trans temp at 175* - 190* in your system IS cool, and IS normal! As such, running fluid through the STOCK cooler (the trans cooler), in your radiator, which is also running 180* - 200* coolant ISN'T bad. It's running at NORMAL OPERATING TEMPERATURE for which GM has designed the transmission and the transmission fluid. Correlating a fluid temperature to what you and I as human beings consider "hot" vs. what a machine considers "hot" are two different comparisons.

I know people live in a world of thinking running everything cooler is better. And that the cooler you run something, the longer it will last. In many respects, yes, that is correct. But for optimum performance, you want to run stuff on the cooler side of what is considered NORMAL OPERATING TEMPERATURE! Running stuff too cool, just because you think 160* is "plenty warm" (when in fact, IT'S NOT), can be just as harmful. Every fluid in your car is designed to run at a certain range of temperatures.

If you expect that adding an external cooler, running the fluid at a much cooler level, say 120* - 160* that you're adding life and longevity to the trans, you're NOT! In fact, you might be doing it just as much harm as running too hot.

[CMNTMXR57]

Oh, BTW, just before you throw out D4 and why GM moved to it (for 2006+ transmissions), the improvements to D4 had virtually NOTHING to do with temperature capabilities/properties lacking in DIII. It had more do to with lubricity and viscosity specs at low temps, as well as anti-foaming properties.

[1fatcat]

Every fluid in your car is designed to run at a certain range of temperatures.

So what should my washer fluid temp be at, professor?

[1fatcat]

Oh, BTW, just before you throw out D4 and why GM moved to it (for 2006+ transmissions), the improvements to D4 had virtually NOTHING to do with temperature capabilities/properties lacking in DIII. It had more do to with lubricity and viscosity specs at low temps, as well as anti-foaming properties.

Oh, BTW, there is no such thing as Dexron 4 (or D4 as you put it). It's Dexron VI (or Dexron 6).

[repinS]

Stock cooler on the 95 gave it temps of 190-200F in the summer, and 210 wasn't a problem in stop and go or if I was a little heavy on throttle use. An upgraded Tru-Cool (as installed by that same fine trans shop that Erik mentioned above) that's slightly larger than the stocker brings that down to 175 all day long, 185-190 if I'm pushing it or hit traffic. Would the stock cooler be fine for someone who grannys it all the time? Probably. But for any sort of enthusiast driving I'm an advocate to put on a better (not necessarily bigger) cooler. Based on the way my 4T60 shifts and behaves, 170-175 is where it's happiest.

The same shop who's been doing transmission of all sorts for years and years, and swears by Lucas in the transmission. They know a heck of a lot more than we do and have much more experience on these things, so that's definitely a plus in my books.

[CMNTMXR57]

Oh, BTW, just before you throw out D4 and why GM moved to it (for 2006+ transmissions), the improvements to D4 had virtually NOTHING to do with temperature capabilities/properties lacking in DIII. It had more do to with lubricity and viscosity specs at low temps, as well as anti-foaming properties.

Oh, BTW, there is no such thing as Dexron 4 (or D4 as you put it). It's Dexron VI (or Dexron 6).

You're right, it is technically 6. I've always just called it "4" for years because it's the next generation of fluid after D3. Tomato/Tomatoe, potato/potatoe.

[CMNTMXR57]

Every fluid in your car is designed to run at a certain range of temperatures.

So what should my washer fluid temp be at, professor?

Please refrain from smart a$$ comments. I got my hands slapped when I (and Pete) took a thread off topic a little while back. I would expect better from participating in a tech topic. Not childish pot shots.