E46 2004 320i Auto Gearbox Issues

sash

///Member
Hi Guys,

Been chatting to a buddy with the above mentioned car and he has been having issues with the car, I did some research on the forum, spoke to his mechanic as well, but am looking for more of a consolidated feedback from the experts with experience.

Background: He hit a really bad bump, which we believe hit the bottom of the engine, the car made a funny noise(similar to belt squeal) upon take off, but seemed to drive ok. On the same drive he also hit a rock(how unlucky is that?) this went under the car, hitting things along the way. This time the car did not want to take off, revs go up car did not select any gear. After a few minutes it did select gear, but it would hunt for gears, change too early, or sometimes not even take off in first.

First problem, the car was driven in that state, probably about 50km.
Second problem, when a mechanic did look at it , he found oil in the radiator, the engine and gearbox mountings damaged, a leak on the power steering pipe(not sure whether it was related or not)

The mountings were replaced and pipe replaced. but doing a diagnostic still shows issues with gearbox and a suspected oil cooler/transmission cooler leak is causing the foam at the radiator cap.

The was driven from the mechanic with no issues at all and now got us thinking, if the gearbox was an issue would the problem disappear and reappear like it has? Would the leak on the transmission cooler not cause intermittent issues in the gearbox( water in the oil).

The mechanic recommended either recon the gearbox or replace whichever is cheaper and replace the cooler. Is it not an option to do the cooler, flush out the system as per nomal and see if there errors thereafter?
 

Gizmo

Banned
I smell another auto to manual conversion coming up...

Sounds like the water cooled transmission cooler got damaged as it sits on the bottom of the radiator. If ATF is getting into the radiator then it is safe to say that water is getting into the transmission, water will kill the transmission and so will lack of ATF. He made a huge and costly mistake by driving the car after the incident, he should have had the car towed...

R22k and I will do the auto to manual 6spd conversion for him, will be alot cheaper than the R35k bill he will get for reconditioning the auto box.
 

sash

///Member
Thanks Gizmo, Would the damage on the box be intermittent, as the car drove perfectly normal just yesterday? Or has he just shortened the life span of the gearbox by running it with less ATF and some water?

I am guessing that fixing just the cooler and cleaning out the system is not an option. The errors showing on diagnostic are.
048: Conv. Lockup clutch, excessive slip (P0740 P0741)
049: Symptom, Gear Monitoring
056: Symptom GLUE
 

Gizmo

Banned
I can't help you any more as my auto box knowledge is so limited that I don't even touch them, unless Im ripping it out to fit a manual...
 

P1000

///Member
Water in an autobox dissolves the glue that holds the clutch material to the plates. So a tiny bit of water will go a long way as far as killing a gearbox. You will be looking at a recon gearbox, or a manual conversion.

The error codes you got means the clutches aren't working correctly anymore. The first one meant the torque converter clutch is slipping, the second means other clutch packs are also slipping, and the third I would have to guess, but it is related to the above. Looking at the codes, you have no choice but to take out your wallet, you will have to rebuild or convert.
 

sash

///Member
Tough Situation, my buddy has the car at a mechanic and is stripping to assess the damage. The cooling will be sorted and then decisions taken on Gearbox once stripped.
 
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