Auto Trans: Several Symptoms

[Chubbs878]

I have a 2003 NA Discovery. I purchased it last April with complete dealer service history to 65K miles. Had 95K when I got it from its 2nd owner, who I assume, picked it up shortly after the 65K service and ceased the expensive dealer service costs. Anyway, I did a comprehensive 100K-type service which included drain/refill every type of fluid & filter existing, replaced entire cooling system, ignition leads/spark plugs, ball joints, Ujoints, brake pads/rotors and so on. When the ambient temp changed with the season last September, the transmission would not shift through 3rd and 4th gears right away. And the colder the Air temp was, the longer the trans would take to begin shifting properly. So even now with temps still under 50F, I have to drive around in 2nd gear and shift through gears, park, neutral for another 10 mins after the truck is already at 194F operating temperature, before I can get on the freeway knowing the trans is warm enough to get up to 4th gear. I have changed the fluid twice, and the 3rd time I replaced the filter as well with no change. One person advised it may be a faulty pump on the trans. Another suggestion I got is a sticky valve I have also added a supplement once. I can't remember the name off the top of my head but it's top shelf and highly regarded; it didn't help the problem either. Finally, I have noticed that I'm not getting TC lockup in 4th. It will lockup in 3rd but in 4th gear RPMs will just climb to 2300 or so where I may drive up to 70 MPH at times. As I recall, this has been the case since it was purchased. I don't think I have ever driven it faster than that but if it should lockup in 4th the same way it does in 3rd, then I don't think kicking it up to 2500 RPM will trip the lockup. Please advise on this.

[Pippin]

At those temperatures lock up in fourth will not take place until the transmission and engine have reached full operating temperature, maybe three to five miles. Could be more as I am not used to those low temperatures. Also of importance is in Drive there is no lockup in third going through the changes. That only occurs when driving in Third. It may be that what you are experiencing is normal.

Nick

[Chubbs878]

At those temperatures lock up in fourth will not take place until the transmission and engine have reached full operating temperature, maybe three to five miles. Could be more as I am not used to those low temperatures. Also of importance is in Drive there is no lockup in third going through the changes. That only occurs when driving in Third. It may be that what you are experiencing is normal.

Nick

Correct, I will have the shifter in 3rd and I get lockup in 3rd. But 4th, may be OK, I have read other posts where cruising speed at 65-70 in 4th will put you at just over 2200 RPM. Maybe I get lockup so quickly after it changes from 3 to 4 that it's unnoticeable. From everything I have read, the trans isn't shifting up through all of the gears early because of perimeters in the computers. But I always allow the vehicle to get up to operating temp before I begin driving and if in D-drive, 1) Gears will not change up from 2 if it's under 35F, 2)will not change up from 3 if it's under 40F, 3) will not lockup in 3rd gear if it's under 40F and not changing up to 4th.

If I know it's not going to shift through the gears I stop in a parking lot and reverse for a bit. Put it in park for a couple mins. Mind you, coolant temps have been at 194-196 since I started driving. Then I will drive it forward and reverse again. Get back on the road with shifter in 3rd. If gears shift up to 3 and TC locks up, then I know that when I reach the highway in 1/2 mile I can put the shifter in drive and it will change through all gears accessing the highway.

If ambient air temps Are above 60F around the clock, I have none of these shifting problems. I allow the engine to warm to operating temp and gears change 1-2-3-4 with no hesitation. So could this be something in the computer? Fluid pump? Other such as MAF? No fault codes by the way.

[Pippin]

If you have correctly filled the Transmission by the book on the fluid changes I wonder whether this may be a thermostat issue. Perhaps Discorevy could shed some light on this or anyone else who might operate in cold conditions or have some ideas?

[Blknight.aus]

those symptoms mostly match for an undefilled transmission with too much cooling because of a sticking cooler thermostat.

they will be made worse if your maf/map are out of kilter and if your TPS is dicey or you have a remapped ECU.

as an experiment, on a cold morning blanket the front of the car and see if that makes it behave more like it should if it does then that points you into the right direction.

while its very cold you can getaway with adding about another 400ml of oil to the trans to encourage it to warm up faster OR you can preheat the underside of the car by putting a car blanket over it and putting a 1000W flood light under the engine at the back of the sump.

[discorevy]

What type of atf are you using ?. Have you done a stall test ?.
Ditto about correct level , you need to drive it as well as having the engine at operating temp as the ecu calculates both parameters before letting lock up happen , the change from 3-4 is harder to pick than the change from 4th to lock up
Pippin , I know Albany gets referred to as north Antarctica sometimes, but it's not that cold :-)

[Chubbs878]

If you have correctly filled the Transmission by the book on the fluid changes I wonder whether this may be a thermostat issue. Perhaps Discorevy could shed some light on this or anyone else who might operate in cold conditions or have some ideas?


I have started threads regarding this issue on US forums, and although others have commented having similar issues, nobody has ever confirmed source or possible resolutions

[Chubbs878]

What type of atf are you using ?. Have you done a stall test ?.
Ditto about correct level , you need to drive it as well as having the engine at operating temp as the ecu calculates both parameters before letting lock up happen , the change from 3-4 is harder to pick than the change from 4th to lock up
Pippin , I know Albany gets referred to as north Antarctica sometimes, but it's not that cold :-)

ATF is Valvoline Dex-Merc "MaxLife" full synthetic. before that I had the standard Valvoline DexMerc. No stall-test, I have never heard of that. Level should be good, always do it by the book. 95% of the time the truck is at full operating temp of 194 F before I begin to drive it. I also added 3/4 bottle of LubeGard Red.

[Blknight.aus]

I see the problem...

just because the engine is reporting 194 deg f does not mean the radiator is, the thermostat prevents excess cooling of the block, the auto cooler is (and this is general to cover more than one vehicle type) either in front of or internal to the radiator and is not linked to the engine temp.

if the auto is coming up as low temp it wont play normaly until it does, if you're reading the engine temp its not indicitive of gearbox temp.


A stall test is brutal on the oil and driveline especially the torque converter dont do it for long but basically...

get it all warmed up load up the brakes, lock on the park brake stick it in D and bury the noisey pedal, the max RPM you hit is your stall RPM. (doing this is also a brutal but effective way to very quickly get an auto up to temp but you dont need to bury the boot, just hold 1500rpm or so for a few minutes...

[ballbag]

I'd dump the fluid, pull the filter apart and check fir debris. Refill, drive for a few days, repeat again.

If there is debris in your filter you may have a blockage in the trans.

My wife drive our heavily laden disco up a 1000M vertical ascent in drive, cooked the fluid and damaged (I think a clutch pack). 20L of fluid and a couple of filters later, it drives well again.

[Blknight.aus]

doing it in D or doing it in 1 wont make any difference to the auto...

high VS low range however....

[ballbag]

Really? The TC doesn't lock in 3rd (and stay locked) at a lower speed than 4th?

[Blknight.aus]

oh, I thought you were talking about off road driving or proper not screwing around, I'm looking out over the bonnet and all I can see is sky, theres nothing but planet in the mirrors the steering's scarey light from the rearwards weight transference Its been that way for 5 minutes now, I'm down to first and I'm really thinking about a snap shift to low cause the engines starting to drop down from max power Rpms towards the max torque point and I'm not sure its going to steady up there kind of steep.

Id have expected it to kick down into 3rd anyway. If you'd damaged a clutch pack changing the fluid wouldn't have helped.

old burnt fluid will allow the control valves to stick and the clutch packs to be sluggish due to friction and it will very quickly lead to deteroration of the Lock up clutch material in the TC (gear selection clutch pack material comes out as a kind of brassy colour, gear metal silver and Tc clutch pack is blackish). To me this points at you got the dying fluid out before it could do severe damage to the trans, its when you change out the old fluid and the symptoms get worse that you know youve got a damaged box.

IF you're unlucky you might have worn the sprags early which you'll pick up when it wont move off in D until you manually select first.

[ballbag]

Becoming a thread hijack but I think worth clarifying for other readers.

My previous posts were bashed out on the phone and poorly written.

What I was talking about was an ascent of 1000M of vertical (on bitumen) so a long, steep climb (Mt Wellington, actually 1250M).

Do that in D and the tranny will haul you up with TC unlocked, if you're not careful. And god bless her, the wife's not. Serves me right for drinking too much beer the previous night and not being alert to it until the red dash light pierced my searing hangover.

For the remaining 2000km of the journey, the vehicle wouldn't move from stationary until tranny was at operating temp.

After the journey, I dumped some fluid and found clutch material in the filter. I'm no gearbox wizz but I know clutch material when I see it.

I drove and reapeated a couple of times until the filter presented cleanly.

And now it drives just like the same clunky old heap it was before the big climb.

[Chubbs878]

Ambient temp is 65 degrees this morning. I let truck warm-up and began my drive with shifter on 3. Going down the city blocks toward the freeway, I didn't get lockup in 3 right away, which is what I expected. I pulled over, put the shifter in Park and sat for a minute. Back in 3, I begin driving again, get lockup in 3rd almost immediately and that's it, ready to go. Truck is much like myself, doesn't like the cold but plays well when its warm out. So, to address the post concerning trans cooler temps actually being colder than engine temps and displayed temperature, is the cold fluid needing to be warmed the origin of the hesitation in shifts and TC lockup, or is it possibly a fault with the pump, solenoid, other? Warmer weather equals thinner/lighter viscosity with the fluid, then again computer parameters controlling shift patterns would produce the same symptoms.

[Blknight.aus]

Ambient temp is 65 degrees this morning. I let truck warm-up and began my drive with shifter on 3. Going down the city blocks toward the freeway, I didn't get lockup in 3 right away, which is what I expected. I pulled over, put the shifter in Park and sat for a minute. Back in 3, I begin driving again, get lockup in 3rd almost immediately and that's it, ready to go. Truck is much like myself, doesn't like the cold but plays well when its warm out. So, to address the post concerning trans cooler temps actually being colder than engine temps and displayed temperature, is the cold fluid needing to be warmed the origin of the hesitation in shifts and TC lockup, or is it possibly a fault with the pump, solenoid, other? Warmer weather equals thinner/lighter viscosity with the fluid, then again computer parameters controlling shift patterns would produce the same symptoms.

Auto box shifting in a D2 is computer controlled and temperature sensing, but you cant see the auto data on the display or the generic readers.

in an old school auto I'd blame contaminated/failing oil and cold making valves and actuators stick.

[Chubbs878]

Auto box shifting in a D2 is computer controlled and temperature sensing, but you cant see the auto data on the display or the generic readers.

in an old school auto I'd blame contaminated/failing oil and cold making valves and actuators stick.


I thought I might undo the harness connections, see anything needs to be cleaned-up and secure/ clip everything back.

[Pedro_The_Swift]

just as an example of temps controlling the Auto,,
My V8 used to lockup into 4th at 60 any time of the year straight from startup.
drive away get to 4th, lockup.

since I installed the trans cooler it now has to warm up,, all year round.