Auto chucks a little hissy fit!

[ytt105]

I've got a 2005 TDV6. I'm towing a tin tent about 2200kg dripping wet.

Been on the road for over two weeks, Canberra/Brisvagas/Hervey Bay. All good (even the weather)!

I normally tow in sports mode with no problems.

But, I was coming up to a hill after being on the flat for some time and instead of changing back a gear or two she went into limp mode (3rd gear only I think) and threw up the F symbol.

I pulled up, turned off and restarted. All good. I then travelled for the rest of the day using the gearbox manually. No problems.

When checking the codes with my Nanocom the problem ones were P0730 and P0735. Both to do with missing 5th gear.

Cleared all the faults, did a hard reset and cleaned the battery terminals. The battery is less than a year old, the brake light switch is about 3 yrs old.

The next day, in sports mode, no problems at all. But it wasn't very hilly.

The next day with a few more hills, it happened a couple of times. But usually I was able to stop it faulting by moving the lever into normal auto mode and back again to sport.

One day was spent driving up and over the Blue Mtns, using manual mode, and she performed faultlessly.

On one occasion when it faulted, only ever if in sport, the error codes I rescued were P0730, P0735, U0402 (another transmission code) and P2199 (IAT).

The oil in the tranny was done at 140k kms (metal sump installed) and she now has 180k kms so I'm going to change the oil again.

Anyone got any ideas?

[justinc]

My guess is that leaving the first oil change until 140k is where the problem lies. An oil and filter change may help however if there are excessive clearances in the clutch packs and wear on the tc lockup clutch then no amount of servicing the trans will help. If The difference between input shaft and output shaft speeds exceeds a predetermined amount then this will generate a fault warning this is usually caused by low line pressure or too much clearance (wear) between clutches and this is the first sign of requiring a rebuild.

Jc

[shanegtr]

Hate to be a bearer of bad news, but around a month ago I started having issues with my trans. Noticed it was starting to make a whine that matched engine revs. When cold it started to hold a higher gear - giving me the P0730 incorrect gear ratio codes. Eventually it was just going straight to 6th and holding it, and reverse wasn't much better. Trans is now on its way (hopefully its arrived) to ZF in Sydney for a rebuild.

[Plane Fixer]

Non ZF oil will also make my transmission do some very strange things. I thought I was up for a rebuild until I went back to the correct fluid, now as smooth as new.

[ytt105]

An update to my original problem. I've still got the problem.

Usually it only ever happens when towing, but a couple of weeks ago it happened to the wife while driving around town. Stop, restart and all is good.

Since then, I've done a second oil and filter change, added 2 tubes of Dr Tranny and travelled lots of kms.

Towed the van for a couple of hours the other day and all was good.

Coming home today she started doing some very funny things. Got the "F" message and changed down manually, (I was in Sport mode at the time", and the gear indicator vanished, as did the Sport or D indicator. The car still drove fine at about 100kph. Then I noticed that if I coasted down a hill the engine revs would go to idle, about 700rpm, when I accelerated all would be fine.

I travelled like this for about 15 mins, then pulled up and cleared the error codes with my Nanocom. My indicator lights returned and I drove home normally from there, about 40kms.

The codes I got are:
P0730 Incorrect gear ratio
P0735 Gear 5 incorrect ratio
P0741 Torque converter clutch solenoid ? circuit performance or stuck off
U0404 Invalid data received from transmission control module

I know the first two are screaming gearbox rebuild, but the loss of indicators and the TCM message are making me think it could be electrical.

Also, I THINK these problems occur after heavy rain or puddle action. Only think mind you as its been many weeks since it first happened. Most of the time it performs great if not towing.

Any ideas?

If it is rebuild time, what options have others found.

Regards
Trev