Transmission won’t select reverse when warm/hot?

[Stuart Tierney]

Hello All,

First post here, and I hope someone might be able to give me some insight as to a repair for this.

The car is a 2006 Mitsubishi i. Small car, Japan market only (save a few that escaped to Europe) and has as the only transmission option a 4 speed Automatic. I’m in Japan, so is the car and I’m asking here because I’m running out of ideas and the locals are of little help.

It now has 150,000km (100,000m, near enough) and in most aspects it’s in far better shape than it should be, except the transmission…

The problem is as the heading says, it won’t select reverse when the transmission is warm or hot. When cold, it selects reverse ok, a little bit of a thump but we’re not rough on it and patient, so that’s no big deal. When a little warm (5-10 minutes driving) it’ll still select reverse, but occasionally needs a little dab of throttle (1500rpm) to get it to select the gear. But past that point, it simply won’t select reverse and needs an hour cool down or more before it’ll select reverse again.

I’m not sure why it does this when warm and not also when cold, so any ideas, even wild shot in the dark ones would be helpful. It might be a pressure problem from the pump, but really, just working out what the heck is going on would be nice. In all other aspects, the transmission (and engine) are faultless. No troubles at all, strong engine, changes great.

A little more information, if it helps.

The transmission is a 4FA1D. 4 speed forward, mechanical selector and electronic control with it’s own trans ECU. There’s a 4FA1C which goes with the non-turbo model, different stall TC on it. Uses clutches to select gears, not bands, and the valve body has 4 solenoids in it, 3 are identical to each other and select (I think) low/reverse, 2-3 and top gear and a different style solenoid which seems to be the TC lock up. These electronic controlled Mitsbishi transmission of this era in this class of car are known to suffer from ‘shift shock’ where the solenoids clog with metal dust (from the gears) and the valve body may also get clogged, so the trans won’t shift until it’s got some pressure behind those valves/solenoids and selects gear in a hard manner, similar to what reverse is doing in this thing.

I know all this as I’ve had the valve body out twice, once to clean the solenoids (which helped a little) and the second to strip down and clean out the valve body (which helped some more) and fit and external spin on filter as the standard filter is a gravel strainer. Also changed the fluid which was originally in reasonable shape and didn’t really need changing. What came out was genuine Diaqueen SP3, and what went in was the same. The dealer that did the previous change was the owner of the car when it was done, and is one of the closest dealers to the factory where the car was made. This car has been looked after on paper, but I don’t know how it’s been driven by the hundreds of different people who’ve been driving it.

Here in Japan, there’s not much chance of having this repaired, shops will want to simply change the transmission. In a city of 300,000 people, I cannot find a ‘transmission shop’ that might be able to do a repair, it’s just not how it’s done around here. Locals don’t do any kind of repair work on their own cars as a rule, so support for doing your own repairs is almost non-existent. I wouldn’t be asking anyone for help if I could pull the valve body (where I think the problem lies) and have it overhauled and put it back into the trans.

I’d like to be able to fix this problem as the trans is great aside from this reversing problem. A second hand trans is going to cost $5-600, and no guarantee it’ll be any better than what we’ve already got. A rebuild is $1500, which is almost what this car cost us. It only has to last 2 years as it’s a disposable car (klnd of) and to take the ‘short trip wear’ off the 2015 Nissan parked next to it, and it’s about half the size of the NIssan which is handy in the narrow streets around here. So I don’t want to put much money into it, but I would like to let it be as good as it can be because it’s a good little car and I hate having something with a problem like this if I can fix it.

Any and all suggestions would be gratefully accepted. If it does mean I should change it, then so be it. If the trans had other problems I’d change it in a second, but other than this reverse problem, it’s fine.

Thanks in advance, I hope.

Stu.

Topic

[college man]

It could be torque converter related, broken gear or clutches that are worn and won’t seal.
This is why it works cold (thicker fluid) and leaks when thin hot.

http://www.ericthecarguy.com/faq/solving-transmission-problems

[Stuart Tierney]

That’s what confuses me as cold or hot, forward drive does not change at all. Very well behaved in forward.

I did notice a small amount of varnish like deposit on the reverse valve in the body which I removed as best I could, but there may be some left inside that I simply can’t get to, even though I had the valve body broken down as far as I dare. Having 2 plates and 3 castings, numerous balls, clips, catches and whatnot, I didn’t want to fiddle with too much. The valve itself is spring loaded which probably plays some part as well, the valve not being free floating.

It needs to go in for a couple of recall issues, and I’ll ask them while they’re doing that if they have any ideas while making sure they don’t actually touch anything because if they do, it’ll be big money real fast and it’s not worth it.

This would be much easier if I was able to get a workshop manual, but that’s not allowed. Don’t ask, it’s mad how common folks are limited in what they’re allowed to see here…

Thanks for the ideas. More than I had to go on, somewhat expected I suppose but still confusing.

I wonder if I could adjust the pressure settings to fudge a fix? As it is, this trans isn’t right and I’ll looking at finding a replacement unit, so pushing it that little bit further might be an option to get it working for the time being? Or just keep playing at gravity reverse and avoiding reverse whenever possible?

(This is all a little mad really. Basically I don’t want to play in the dirt changing it over all by myself. It’s a pain of a job and I don’t want to do it!)

Stu.

[Author]

Replies