I've seached the forum and can't find anything that would help me, so here's another Auto Transmission question. When I'm on the highway at higher speeds the transmission seems to be holding the car back. I can feel the engine wants to go, but the tranny won't let it.

I sure that other posters haven't had a problem at 80mph (145kph)??

Anyways it seems the transmission is pushing to keep up the speed at 145 kph, and then when I use overdrive to pass someone (now at 160-165kph), it shifts from overdrive back to 5th constantly. Is the transmission too tight, or what do you think is causing this? Have you had any experience with this type of issue?

It's quite draining to drive on a long trip with this going on, I feel I'm having to push the car on, rather than sitting back and enjoying my nice ride. I'm going in to have the car serviced if you can give me an idea of what to ask for, it would be very appreciated.

 

The engine revs very high at cruising speeds (3k rpm at 80mph). I believe I have noticed the same sensation as you. It seems like the car just doesn't want to glide.

 

I have to admit I'm having trouble understanding the "sensation" you're feeling. The first thing to remember is AWD vehicles have the added resistance of the transfer case which drives another axle. As for the car downshifting from OD into a lower gear, that's what it's designed to do under a load. And 5th gear IS OD, there is no 6th gear.

For each gear you also have a torque converter lockup which could actually feel like another gear. The TC is programmed to allow slipping to make shifts smoother and keep the engine rpm in its power curve. Once the rpm reaches a preset point associated with your current accelerator position, the TC will lockup giving you full torque and maximum mpg.

As you push farther on the accelerator pedal, you advance through the shift tables which tells the trans to raise the TC lockup and gear shift points. Once you pass such a point, the transmission is told to either unlock the TC and/or downshift to give you your desired effect... speed up. It works the same for upshifts.

That is why when you lift off the gas, the car upshifts. And when you stomp on it, the car downshifts. It's simply working off a predetermined table that says, "if you reach this point do this, this point do that". By pushing the "Sport" button, you're working off completely different tables with higher settings giving better performance at the expense of MPG.

Look at this sample of one of the trans tables from a Chevy and you can see how the trans reacts to your throttle position. There are tons of tables for a modern trans just to control a few gears. For example, if you're in 2nd gear with the throttle at 25% the car will shift in 3rd when it reaches 18mph. But if you push down to 75% throttle it won't shift until it hits 28mph.

This isn't to say you aren't experiencing a problem but at least this gives you an idea of what the trans is trying to accomplish at your request.

 

Thanks C5. The feeling is just as AML says, the car doesn't want to glide at 80 MPH. I have a 3.0 so I'm expecting alot more glide than I have at that point. I'm not hitting the accelerator all the time (except for passing as mentioned), but it seems it's always a push (from me) to maintain the speed and the leg gets tired. If it's just the way the car is made then it's a no go for long trips, long trips here being 6-8 hrs. Or get rid of the AWD linkage for the summer months..

 

Would using the cruise control help? Then you can sit back and let it do what it wants. I would think in a 6-8 hour drive there would be a lot of open highway miles to rest your leg.

 

It sounds like you're just experiencing a normal AWD system. Because 2 drive axles are always engaged the engine has that extra resistance to overcome at all times. That resistance is exactly why AWD models always get less MPG than their 2WD counterparts. There's always a trade off. In this case it's superior traction traded for gas. It's always a good idea to get the fluids checked just to make sure everything is well lubed.

Also, I can tell you the TC doesn't seem to unlock as soon as other cars I've driven. Some cars are quick to unlock as you slow down but not the X. My guess is it has something to do with the AWD performance. It's like the engineers want the TC locked as much as possible for a more sure-footed experience. But that has nothing to do with highway driving where all cars are locked at high steady speeds.

And lastly, 80mph is not the most economical cruising speed for an auto X. It's probably more suited for 55mph tops. Since it shifts into 5th at 40mph (45mph sport) it probably doesn't sip gas much afterward. It's probably more like gulping by 80mph. As a comparison, my C6 gets about 30mpg on the highway because the V8 isn't even breaking a sweat. It's basically idling along at about 1700RPM at 80mph. So if you like to "glide", drop in a V8 and stock up on transfer cases and transmissions.

The one thing I miss on the X is an "instant mpg" calculation. It would make it so much easier to learn how to conserve fuel.

 

That's an easy fix: plumb in a vacuum gauge!

 

I know exactly what the OP is talking about.

 

I just had the transmission fluid, transfer case, and rear diff fluid replaced. Anything else I could do that would help?

I had a Mercedes SUV that was geared similarly to the X-Type. Cruising RPM at 80mph was about 3k rpm as well. Never really felt the same kind of resistance as the X. We're talking about a 4WD SUV pushing 5,000lbs.

It was interesting when I first drove it though. I'm already in 3rd gear by the time I'm past a typical intersection at a redlight. hhaha

 

Sunroof open or windows? just thought i'd ask (drag coefficient)
anyways,
it's called: "underpowered." and poor tranny ecu programming.
for a vehicle that weighs 3,600lbs, the torque is VERY inadequate. Plus, JAtco components which are now considered the Yugo of tranny products amongst most gearheads.....

 

my favorite aspect of the x-type is slamming the gas pedal and...wait, wait, wait... V'Room! there she finally goes! (3 seconds later) I wish someone would make a Sprint Booster for the X-type.

 

Weird, I just drove in at highway speed (130 KMH) and didn't notice the resistance you guys say. Also passing gear is only about .5 seconds, I think mine is pretty quick to switch down.

I'm going to do the tranny fluid as soon as it's warmer out to see if there is any difference. Mine is a very soft 2nd to 3rd shift, I'm hoping the fluid change will change that.

 

Thanks everyone for your posts, I have more info to discuss with the mechanic. Are there any issues with making the X-Type a 2WD for the summer and then changing back to AWD? Or would it be the point of no return?