Yet another gearbox issue for the E53 4.4i... please help!

[gadden]

Hello all,

spent hours of reading through various threads, but i found only 1 similar case for a 4.4i E53 with external trans cooler and a colder thermostat .

Mine is an EU version 4.4i E53 2001 (pre-facelift)

Long story short, i've had issues with the model. I've went through a torque rebuild 50k kms ago + fluid change because of hard downshifts. Afterwards done external cooling as it was again starting to act up after 30mins+ drives. Ext cooler was done around 20k kms ago give or take a couple of thousand.

So far so good. I believe the torque was at its limits now and will had to be rebuild again (first rebuild i don't thrust very much, shady mechanic).

This was a couple of days ago when i went to the shop and told them to change the thermostat for a colder one. Reason for this was the 2nd hose failure in 6 months, leaving me stranded. Car is too old for 106 degrees Celsius. The colder thermostat is from a 7 series diesel and a perfect fit (+a resistor to avoid the errors as it is mechanical).

All good, car runs at 95C now... but i am now getting a sort of stutter or jerking in what seems like switching up form 3-4 gear. This is only visible with very gentle throttle handling - i.e. stuck in traffic, or keeping a constant speed at 1.5k - 2k RPM. Happens on hire RPMs as well if my foot is stationary on the gas. If i give it a bit more gas - doesn't occur, shifts with no issues. Its as if it tries to shift to 4th but doesn't make it

ATF temp is at 75C now. As much as i read everywhere that people having trouble with high temp, is this a low temp for a heated-up car? I'm baffled with it now, no idea what to do except maybe try and put the original 106C thermostat and see how it goes, somehow though i believe this will not cure my current problem. Prior to the colder thermostat change, it always ran smoother when colder or not fully warmed up.

Should i bother with looking into reverting to the original thermostat, or removing the ext cooler to see if any of these mods is the reason for the problem? Or its just a coincidence that it happens now after the colder thermostat change...

Timing chain replacement was 10K ago, if it matters.

Of course my fear is going to the trans shop for a rebuild as i recon they will want to rebuild the whole thing for half the money the car is now worth.

Any input is appreciated.

Sorry if i messed up somewhere with the English, not my native language

Best Regards

[gadden]

Sadly no input, but to any who it might concern - the torque was pretty much gone.

However the actual problem was that the heat exchanger (radiator) got busted and the gearbox had coolant in it. Needless to say a full rebuild will be required

I should've replaced that piece of crap along time ago, lesson learned the hard way.

Can the colder thermostat be the reason for higher pressure?? This happened right after the install of a 90C thermostat from the 7 series diesel (original BMW and brand new, direct fit)? Is it just a coincidence? I'm going mad with this car

Any thoughts appreciated

Best regards

[guntherrex]

sad to hear about the busted gearbox... I guess the temperature issue would have been a good indicator. Will keep that in mind for the future.

I don't think a cooler thermostat would create more pressure, quite the opposite actually

[bmw983]

after the work was it Rest and the instruction followed the ZF/BMW have like 1hr reset prodcure which Teaches the auto to relean and find the optional point to shift if there any issues then during that prodcues could been picked up i know there was ESG update awhile back for shift issues ecta