Hi, i just bought a 03 xjr from a dealer. I've encountered a hard shift situation a couple of times and want to see if I should be concerned.

Both times this issue manifested itself, I had driven the car after sitting overnight, parked it for 2 hours, and restarted to run an errand. So it's cold, but sitting in frozen overnight conditions cold.

Put the car in drive, starts off fine in 1st gear, it picks up speed normally, but holds the gear longer than usual until 3k rpm, then an extremely hard shift into 2nd, hard enough that even my wife noticed. But then it's fine.

Anyone else encounter this? Thanks in advance

 

Two questions:

Does it do that with the engine/transmission warm?

How long/miles since you bought it?

 

Hi, both times the trans was relatively cold. Only about 250 miles since I bought from dealer. It has a 90 day powertrain warranty, but it's going to be one of those things that's impossible to replicate in front of a mechanic.
It shifts fine when it's warm. And usually fine when it's cold too, just happened twice so far.

 

I wouldnt worry about a hard shift on a cold trans, people think the radiator trans "cooler" is just that. But its to speed up the transmisson fluid temp since the engine coolant heats up faster than the tranny And it keeps the fluid at a more stable temp. I have tested many trannies in cars and trucks bypassing the radiator and useing a external cooler on in all cases leaves to a below proper operating temp in most driving conditions. the exceptions when needed are higher stall speed converters, towing, heavy loads and sustained hipo driving. in all other cases the temps stayed lower than recommended for proper and consistent operation.
so in short, a cold tranny can exhibit different shifting when cold and not always duplicated.

 

Stupid question, but relevant....

Did you leave the Sport mode button on when you started it? That usually causes the trans to shift very hard when cold.

 

i am having the same issue...and my wife noticed too!...great comments...i'll let you guys know more details about mine, when i leave it in S...i have a 2001 XJR and have the same issue...

 

Good news bad news. Good news is I have had the same exact problem for a year and 8 months, the car is running fine otherwise and it seems to have not been as frequent the past year. Bad news no one I took it to could identify it. Mine also makes a camera shutter sound after driven, put in park or neutral, an let idiling. As far a reducing your frequency try these steps you:
1. anticipate the hard shift ie the surging toward 3k
2. shift to neutral with foot off gas
3. shift back to drive and you should avoid your hard shift, works 99% of the time.

Xjr shutter sound video (note: not sure if this is related but would be interested to know if anyone has had similar sounds and symptoms)
http://www.youtube.com/watch?v=5SMXrGR_kSo

 

Couple things.....

Hard shifting when cold is usually cross leaks between valve block and trans body, when the trans warms up the aluminum expands and closes the gap.....If you're really concerned about it, pull the pan and gently snug up all the valve body & solenoid bolts, etc.

The shutter sound is often an aftermarket filter sucking air where it intersects the pump pickup...the cure is to use an OEM filter assy.

Probably a good time to change the trans fluid anyway!

 

I have experienced this same synptom on three different occasions. One other symptom I have seen is backing out of a parking space then moving the lever into drive will drop in very hard. Again, this has only been a cold start condition.

I was thinking it was the cold tranny as well but I then started wondering if I should look into a trans service w/fluid and filter. I'm at approx. 52K miles, yet 11 years, so it may be due.

 

i am starting to experience this more and more...it seems to be from 2 to 3 third gear though...it also happens to me when the car is warm...it tends to happen as i am driving very slow about 15-20 mph as i take my foot off the gas...it is like it is anticipating me accelerating, but i take my foot off the gas...i am wondering if it is the learning of the transmission that is thinking i am going to be accelerating??? any ideas?

 

any ideas what could be causing the hard shift when the car is warm...it happened again tonight...and now i am getting worried...

 

just an FYI...my hard shift problem doesn't seem to happen when I have it in S mode...could it be related to the tcm module and the tranny not learning right? or does it have something to do with he tranny staring in 1st when it is in S mode and 2nd when it isn't in S mode...the problem only happens when the car goes from 2nd to 3rd...

 

Do you have any other issues, such as "restricted performance" warning light or check engine? If you don't have any codes, do you switch in and out of sport mode frequently? I just tested a few conditions in my car. If I have it in sport mode and pull into my garage, and turn off my car then turn off sport mode... then let the car sit (off), I can go back, start up the car, let idle for a few minutes, backout slowly, and the car will hold 1st gear (even though it's not in sport mode) and SLAM into 2nd gear (possibly third gear since it's no longer in sport mode) at about 2,500 rpm. However, under these test conditions, I cannot produce it 100% of the time, only about 1/3rd of the time... but considering my car never has this problem to begin with, it's some info for you worth investigating further. It's possible the computer is getting confused on which mode you're in.

 

thanks for the info...I don't have any lights or restricted performance...as long as I keep it in S I have no issues...i guess the car just want to go fast...

 

Normally transmissions do not have occasional problems -- and when problems start they do not go away. The Mercedes transmission does have a few electrical issues that can be looked into.

If you are the original owner then you know if any servicing was done - often these cars are now on the third and forth owners and the service information is lost. If any servicing was done it had to be with the correct fluid and filter - often to save a few $ this is not done. The car would have been better off if they would have left it alone.

You need to check for any leaks and verify that the fluid is at the proper level and move on from that point. I have not touched mine - but I do have experience with this transmission in MB's and Porsche's. If you do a google search you will be overwhelmed with information.

 

so i did some more playing around...i can replicate the hard shift problem...and think i have it nailed ok here it is

with sport mode off and the foot brake on...i can switch betwen drive and neutral and after about 10 times of going back and forth between drive and neutral i can feel when the tranny goes into 1st instead of 2nd...i then start driving and the harsh shift happens...it is pretty easy to recreate...this also happens when the tranny is cold or warm, it doesn't matter in my case...

bloweraddict mentioned that Hard shifting when cold is usually cross leaks between valve block and trans body but this is normally attributed to cold condition, i can recreate the problem both warm and cold...

any ideas what is causing it..i am trying to figure out if it is the tranny or the TCM...is it mechanical or electrical...any thoughts would be great...

from what i am guessing, the tranny is in 1st, but the TCM thinks she is in 2nd....that is my theory so far, and wondering how that would happen...something is a miss

this is one of the last bugs in my car that i need to take down to china town...

 

This might be some sort of a record from last post to current post!

As to thinking it is in 2nd I agree. Mine does this rarely, but each time it is not in sport mode and it does behave as if the computer thinks it is in 2nd. Also, it shouldn't even be in 1st as it is supposed to start in 2nd.

 

yes I do that...startup old posts

ahh good point ...so the TCM just thinks my cars in 2nd when it is actually in 1st...

so..then I wonder if this is a solenoid issue...being flacky or something

 

Change the fluid before you end up spending $6000 on a transmission. I just like did!

 

Did you check to make sure the fluid level is corrrect and that the electrical connection to the transmission is not leaking?