Shift points for 5 speed automatic- max speed to go into 1st gear?

[SanDiegoXLR]

Hi All,
Has GM ever released suggested shift points for the 5 speed automatic XLR?
For example, at what speed is it ok to downshift into 2nd gear, into 1st gear, etc?

The reason why I'm asking is I recently test drove another car, and the salesperson told me NEVER to downshift into 1st gear if you are above 10 mph, which I thought was a bit strange.

I've searched in the owner's manual and the forum, but can't find this info. I'm thinking the transmission is smart enough not to allow shifting that could cause damage (e.g. downshift from 5th into 1st while going 80mph, etc).

Thanks,
Mark
2005 XLR

 

[ald42]

shift points

Hi All,
Has GM ever released suggested shift points for the 5 speed automatic XLR?
For example, at what speed is it ok to downshift into 2nd gear, into 1st gear, etc?

The reason why I'm asking is I recently test drove another car, and the salesperson told me NEVER to downshift into 1st gear if you are above 10 mph, which I thought was a bit strange.

I've searched in the owner's manual and the forum, but can't find this info. I'm thinking the transmission is smart enough not to allow shifting that could cause damage (e.g. downshift from 5th into 1st while going 80mph, etc).

Thanks,
Mark
2005 XLR

I believe it will not shift into lower gears until it reaches the correct speed/rpm but I don't know the speeds/rpms for each down shift.yes smart trannys.

 

[XLRATING]

Basically, it will save you from some of your own stupidity -- I couldn't remember exactly what so I searched the PDF of the manual on here (under Tech Center -- easier to search it on here than flip through the book) and found this:

Not all manual downshift requests will be accepted by​

the transmission. To prevent excessive engine rpms, each gear has a maximum vehicle speed associated with it. Any downshift request above this speed will not be allowed by the transmission.
​

If shifting is prevented for any reason, the current gear will flash multiple times in the DIC, indicating that the transmission has not shifted gears. Some automatic downshifts may occur to maintain minimum engine speed. This only happens the vehicle is left in too high of a gear for the vehicle’s speed. For example, if you have been driving in fifth gear range and come to a stop without manually downshifting, fifth gear will continue to display in the HUD. The transmission will automatically downshift to second gear. As you begin to drive and accelerate, the transmission will automatically upshift as quickly as possible to the selected fifth gear.

In higher gears, an automatic downshift will occur if you press the accelerator pedal to the floor. This feature provides adequate acceleration capabilities if you forget to downshift manually.
​

 

[SanDiegoXLR]

Thanks for the quote from the owner's manual. Sounds like our transmission is actually quite advanced ;-)

What's shocking is I was test-driving a 2013 Jaguar F-Type when the dealer was freaking out and telling me it would damage the auto transmission to put in 1st gear above 10 mph??! Either he didn't know what he was talking about, or its transmission isn't as durable/well designed as ours? Although Jags aren't known for reliability!

 

[mtrocket]

What I would like to know is why the XLR transmission does not shift down automatically when the cruise it on and you're going down a hill in order to keep the speed set on the cruise. My Jeep Liberty does this, so why doesn't the XLR???

 

[SanDiegoXLR]

Yeah....that is definitely one short-coming of the cruise control.
There's a very steep, large downwards hill by my house that is a known speed trap (motorcycle cops hide out at the bottom of it and issue hundreds of tickets). I'll set the cruise at 45 mph, but the car always creeps up to 51-55 mph. I've learned to just put the car in 2nd and take my foot off the gas so that I don't exceed 45 as I go down the hill.

 

[MarkSki]

Thanks for the quote from the owner's manual. Sounds like our transmission is actually quite advanced ;-)

What's shocking is I was test-driving a 2013 Jaguar F-Type when the dealer was freaking out and telling me it would damage the auto transmission to put in 1st gear above 10 mph??! Either he didn't know what he was talking about, or its transmission isn't as durable/well designed as ours? Although Jags aren't known for reliability!

I had a 2000 XK8 and the tranny is german. You can shift into 1st around 25 mph, I think the XLR is the same. Take yours out, drive in 2nd around 30 mph then put it into 1st and see at what speed your tranny kicks down into 1st. You won't hurt the tranny, it won't allow you to!

I think that dealer was scared you would exceed 3000 rpm! If it were me I'd have given him a 'test drive'!!

UPDATE: I just finished washing and waxing my Grey Jewel so I took it for a little spin. My 2004 shifts down into 1st at 30 mph and 3500 rpm.

I suggest you drive in 2nd to 32 mph then put it into 1st. You're not going to go over 3700 rpm.

 

[ECurtis]

........There's a very steep, large downwards hill by my house that is a known speed trap .......

Would that be the hill as you go down toward the airport from Hilcrest? People used to always speed there.

 

[SanDiegoXLR]

ECurtis- It's the hill on Genesee Ave in University City/52 freeway by the high school and Rose Canyon.
The hill by the airport is a speed trap too!!

I tested my car the other day.....1st gear is good all the way to 45 mph before shifting into 2nd ;-)
Haven't really seen too many posts on here regarding transmission repairs? I wonder if shifting a lot causes additional wear and tear. Or was the XLR built under the assumption that this feature would be used a lot by some drivers? Does the transmission fluid need to be changed every 100,000 miles? Or more frequently if shifting yourself?
-Mark

Would that be the hill as you go down toward the airport from Hilcrest? People used to always speed there.

 

[MarkSki]

What I would like to know is why the XLR transmission does not shift down automatically when the cruise it on and you're going down a hill in order to keep the speed set on the cruise. My Jeep Liberty does this, so why doesn't the XLR???

I would guess without down shifting you would get better gas mileage.

Older cruise controls allowed a 3 mph drop and rise from set point.

I notice my ACC will run 1 mph above my set point (usually) and will drop 1 mph going up a hill. As for going down the hill, it gains as much as it wants to until you apply the breaks or manually downshift or the road levels out.

 

[ECurtis]

ECurtis- It's the hill on Genesee Ave in University City/52 freeway by the high school and Rose Canyon.-Mark

Yeap, Know the area.