2nd gear slipping

[RaspiestMoon70]

Hi all! I have an 06 grand voyager 2.8 auto and I'm having an issue with the trans slipping. 

 

I bought it 2 weeks ago and wasn't sure, but last week it started slipping really badly. 1st seems fine, but it slips up to speed from a stop and changes up nearly straight away. 2nd is the worst. It's slightly better when cold, if I just manage the throttle I can keep the slipping low, but when hot it slips awfully and I have to rev the engine up to 2.5k to make any progress. Most of my driving is around town so you can imagine this can cause some issues. 3rd will slip either during the shift from 2nd to 3rd, or if I'm trying to accelerate up a hill, and 4th is generally locked up so there's no slipping at all there. 

The fluid is pretty dirty so I'm going to drop the pan this week, put some fresh fluid in with a bottle of stop slip, hopefully this will make it better but if it doesn't, what's my first port of call for fixing it? I have the torque pro app on my phone which doesn't show any codes, though I don't know if it will show trans codes so I'm tempted to stop by a garage and have them plug it in with a decent reader just to check. 

Would it be worth changing the solenoid pack? Or if the fluid change doesn't work am I looking at a recon gearbox? If you need any more info please ask, I really want to get this sorted and I don't have the time or money to just leave it with a specialist, and I don't want my first proper auto to be a very expensive learning experience. Thanks

[RichardM]

1. I am no expert on these auto boxes (or anything else on these over computerised beasts, the combination of electronic and mechanical 'challenges' complicate things but having searched and read many problems concerning the transmission I would suggest the following approach.

Being as it gets worse when warm / hot I would suspect an oil change might resolve the problem.

Change the fluid and filter as you state. Do not add any 3rd party product to the oil initially, see how it responds to the new oil first. You must use ATF4.

Whilst draining the old fluid check with your fingers for 'grit', if the fluid is smooth then it's a good but not conclusive evidence of a sound box.

As far as I understand it the computer needs to relearn it's cycling after an oil change - didn't seem so when I did mine but have read that a number of longish runs are required including kick downs, up-hill climbs etc. to optimise the gear change 'point'. Also this gives the box's valves to be 'washed' with the new fluid and may clear any partial blockages caused by old contaminates.

I wish you the best of luck & hope it's nothing more than ancient oil causing the problem. Please update the thread with any results to help everyone else.

 

Richard

 

[maxcaddy]

Unfortunately you don't say how many miles it's done, which would be a good indicator as to whether or not it's even worth the cost of changing the oil .

If say we're talking 150 - 175K, then maybe an oil change and filter will save the box. If it's more than say 200K you'll be very lucky IMHO.

If you only bought it 2 weeks ago it is unbelievable that the previous owner didn't know there was a problem, and as such sold you a dud. A few words need to be exchanged.

[Sergejs]

I have same year and same engine car and exactly the same problem. I have changed filter and oil, but it didn't help. It actually became slightly worse. The oil was black and magnets full of fine metal particles. When you change oil, you actually change just a half of it, as a lot of oil (about 4 litres) stays in torque converter and radiator. Anyway, for now I have bought Lucas oil transmission fix. Didn't put it in yet, but I will. I think previous owner used it already and it explains why slipping got worse after oil change. In any case, these are not good symptoms you/I have. Dark oil means wrong pressure and fluid overheat and this means you need to repair your torque converter and of course, if you remove your transmission from the car, it make sense to check the gearbox for worn friction discs etc. I have tried all sort of scanners and no errors. I wonder if Transmission ECU actually responds. I'm mentally preparing myself for transmission removal and reconditioning it in my garage as DIY project. To give it to professionals will simply cost more than a car (around 2 th.). Luckily, this is very simple and popular gearbox, which have been used on many cars and very long time (41TE, A604). If you will type it in google, you will find plenty of info. I'm not recommending to go with e-bay second hand transmissions as it is very low probability to get a good one. These transmissions need frequent fluid change and many owners doesn't know that and therefore the average lifetime of this transmission is 100K. I hope it helps. Sergejs.