Sunday 24 February 2019

Hiace Automatic Transmission/Gearbox, problems & solutions

Hiace automatic transmission sump..

I’m writing this article because it could save you a lot of money, time, stress, and needless disruption when travelling, and get you out of some seemingly mysterious problems single-handedly and back on the road.. πŸ‘ŒπŸ»
At the time of writing this, I’ve been living and travelling in the Hiace for seven years now, and in that time I’ve come upon most problems we can have with the auto-gearbox on the Hiace. Mines a 2.8D 3L engine type by the way. I’ve also had to go through quite a bit of stress and problem solving along the way, so I want to share what I’ve learned..

So in my experience so far, there are five transmissions problems that can occur, three of which you can fix at little cost and hassle to yourself. Two are roadside fixes if you have certain things in the van with you..

1. Symptoms: The gears start to slip and lose drive in the higher gears at speed, dropping into lower gears. 

Problem cause: The transmission oil has leaked out of the system, so there’s not enough pressure to engage the higher range gears properly. Often the gearbox sump gasket which is made of cork, has depleted and the oil has slowly dripped out to a point where you lose drive. It has also been reported by another owner that a leak occurred where the gearbox cooling lines connect to the side tank of the radiator via rubber hoses. 
Check the dipstick to confirm this is the cause (procedure below).

The gearbox dip-stick

Solution: first check the ATF (automatic transmission fluid) level.  With the ENGINE RUNNING.. Remove the red dipstick in the engine bay (ATF dipstick). There are four notches near the end. The lower two are the cold range, the upper two are the hot range. Clean the dipstick and dip it again.. check the ATF level, it will likely be very low. It should be between the two notches corresponding to the gearbox temp. Hot after driving or cold if it’s just been started. 

'Cool' and 'hot' marks on the dip-stick
It is also marked 'Dextron II' for recommended oil.

Next, check the sump gasket and gearbox generally for signs of leaking, tighten the nuts hand tight on the gearbox sump with a socket.
Now top up the ATF level to the correct range.. this is done, through the dip stick hole.. seriously! 
Procedure.. ENGINE RUNNING.. remove red dipstick, use a small funnel that fits in the dipstick hole and a plastic measuring jug. Add about 250ml at a time, and after each shot of oil, get in the cab and move the gearstick slowly through all the gears with your foot on the brake. This is to allow the oil to enter all the chambers in the box as much as possible. Then dip, check and repeat this sequence until the oil is at the correct level for the hot or cold temperature of the engine/gearbox. Once it is within the range you are good to go! You should have full power in all gears again. It cost you £30 for a can of ATF!

I use a small funnel to top up the ATF..

The level is specifically accurate only between the hot marks, so next time you drive the van from cold, go about ten miles, then check the level again until you’re confident it’s correct. Driving with too much oil can cause problems if you don’t drain some soonish. Drain oil through the plug in the gearbox sump pan if you need to. Get that gasket replaced (with a rubber one) AND some gasket seal, as soon as you can. Get the filter cleaned when thats being done. 
Preventative medicine: so this will never happen in the first place: regularly check the gearbox for leaks, these vans are getting old and that cork gasket will be breaking down. Get the gasket replaced at any sign of depletion. Check for other leaks around the oil cooling hoses and pipes. Regularly check the hot mark levels after driving ten miles, and don’t forget to leave the engine running to get the correct reading. 

2. Symptoms: the van is reluctant to shift into 2nd gear and refuses to go up the gears as you drive off, or won’t shift out of first at all. 

Problem cause: The kick-down cable has become stuck in the extended position stopping the gears shifting up. This is due to the lubricant and glide in the cable sheath drying out completely over time. (The kick-down cable controls the pressure in the system to hold the gears as the gearbox shifts up . It also causes the box to downshift to a lower gear when you put your foot right to the floor to overtake or on a hill.)

Solution: Lubricate the kick-down cable. Disconnect the kick-down cable from the throttle linkage. Remove the red rubber dust cover. Squirt WD40 or a light oil down the cable sheath. Work the cable in and out by hand, until it frees up and you can push it right in again, until the cable stopper touches the sheath. You may wish to leave the cable propped upright overnight to allow the oil to work its way down the sheath if the problem is not eliminated right away. Reconnect the cable and then adjust it as follows:
Open the throttle fully, then adjust the kick-down cable (with the two nuts) so that it is fully extended at this point. Now, slacken off the tension so that there is still a little extension of the cable possible at this point. This will give you nice firm shifts.. If you slacken it off further there will be more 'slip' in the gear changes, eventually reaching a point where it will not hold the gear firmly. Lock it off using two size 14 spanners. Done!

Loosen one of the adjustment nuts to detach the cable
and remove the end ferrule from the throttle linkage.
These nuts are also used to make the adjustments to the cable tension, and lock it in.

The kick-down cable detached..
Pull off this orange cover..

Put oil or WD40 down this hole and work the cable in and out
until the stopper sits into the hole again..

Preventative medicine: when doing some maintenance on your engine.. disconnect the kick-down cable from the throttle linkage and squirt some oil down the sheath. This should eliminate the possibility of it happening. πŸ‘ŒπŸ»

3. Symptoms: the transmission will not shift into overdrive (top gear). Sometimes it will, sometimes it won’t, then it won’t at all. You switch o/d on and off on the gearstick to no avail. You’re stuck driving at 45mph the rest of the day πŸ™„ 

Problem cause: there is a solenoid on the left side of the gearbox which is operated by that switch on your gearstick. It’s job is to let the ATF fluid pass into the overdrive chamber when o/d is switched on. It’s failed and is stuck in the closed position. 

The o/d solenoid is located on the left hand side of the gear box (passenger side)
a. Get the solenoid replaced. 
b. Bypass the solenoid so its always ‘on’. I wrote an extensive post on this previously.. here’s the link..
You can drive with it bypassed indefinitely but I do recommend replacing it.. on journeys with long hills you may wish to accelerate to a higher speed with the o/d off. The torque converter in the gearbox works hard about 45mph on a hill if you are accelerating and can cause the ATF to overheat. If you can switch off the o/d you can eliminate this problem. I’ve had this issue in Spain on long steep motorways etc but never in the uk. 

4. Symptoms: The ATF temp light comes on when driving. Usually it’ll happen on a hill. Pull over as soon as you can!

Problem cause: the temp has risen in the ATF in the gearbox to an unsustainable level. It can be due to low ATF level, or inefficiency in the vehicle cooling system (the gearbox oil is cooled through a heat exchanger in the side radiator tank).

Solution: firstly, pull over as soon as possible, if you don’t the increased temp will start to also overheat the radiator and engine etc causing bigger problems. Second, at the roadside, leave the ENGINE RUNNING. Then simply wait, usually about five minutes until the light goes out. You can now drive on but if your on a hill, stop again if you need to if the light comes on. 
Soon after your trip, have the entire cooling system flushed out and get it cooling as efficiently as possible. 
You can add an additional ATF cooler (as well as the radiator side tank one), or as I have done, bypass the radiator and cool the ATF in the airflow in front of the radiator with a separate oil cooler. This eliminates a cycle of heating as the engine temp and gearbox temps are regulated separately. You can debate this endlessly as to which is the best system! But mine works well in practice. 

The ATF cooler mounted in front of the radiator..
This one came off a Mercedes car

Preventative medicine: flush your cooling system, get a new radiator fitted, add an additional ATF cooler, or bypass the radiator altogether (separate cooler). 

5. Symptoms: the gearbox seems to slip more and more often, especially on hills, then after time you lose drive in certain gears, even reverse. You’ve kept an eye on leaks and ATF level and all these things are ok. 

Problem cause: The gearbox internals have actually worn out. 

Solution: this will involve an extensive gearbox rebuild at quite a cost, but it’s worth it as afterwards it’s like having a new gearbox and your van will go on for years. 

Preventative medicine: (you really don’t want this to happen so.. always check and keep your ATF level correct. Once a year drain the ATF and refill. Also remove the sump pan and clean or replace the filter. 

Things to keep in the van on a trip to get you out of any gearbox related problems:
1. A 5 litre container of ATF. Any Dextron II or III or more modern oil will do. 
2. A funnel and jug, or other method of adding oil through the dipstick hole. 
3. A socket set and basic tool kit. (2 x size 14 spanners for kick-down cable.)
4. A ‘can do it myself’ attitude πŸ˜„

So I’m very happy to share this info and experience with the other Hiace Camper owners out there. (Some of the solutions will no doubt help other automatics as well.) I hope you never have to deal with these problems, but this will make your trip go a lot more smoothly if you have a gearbox issue, and save you a lot of cash too. 

A final word.. you could avoid all of these problems by buying a van with a manual gearbox in the first place!! Old autos are going to have issues as the years go on, but I don’t plan to part with mine πŸ˜„

Have fun and see you soon πŸ‘‹πŸ»

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