Gearbox problems.

[JKO]

Is the problem with the gearbox only in the 2007 model?

Jenny Marchant, England
Mitsubishi i-Miev 2007
2 star review
Great City car, fun to drive - only problem, 3 months out of warranty, @ 49,333 miles and the gearbox has gone!!! A £2,200 bill to get sorted. Now, the car has been serviced by a Mitsu garage at every interval, any problems have been reported and dealt with by Mitsu.... all in all a 3 year old car, that is an automatic should not need a new gearbox!! If your car starts to emit very jerky gear changes in kickdown, it struggles on creep, this is the start of a knackered gearbox. Be wary!

Responses to this review
I have the same problem, the only thing is I’m one year out of warranty. I have only done 13,000 miles and have a bill of £3800 - Theresa Shepherd from England

http://www.roadtestreports.co.uk/cars/mitsubishi/i-miev/

 

[siai47]

The "gearbox" in the BEV I-MiEV is not related to the transmission found in the gasoline powered I-MiEV referenced in this thread. Not an issue for anybody with a electric I-MiEV.

 

[PV1]

Was the i-MiEV even available to the public in 2007? As far as I know, the i-MiEV was in a test phase at that time and only the i gasoline model was available.

 

[RobertC]

The gas powered Mitsubishi i was sold in Europe in 2007. The electric powered i MiEV was not sold to the public in the UK until 2011. These gearbox problems must be with the gas powered i.

 

[jray3]

These gearbox problems must be with the gas powered i.

That's a relief. :roll:

Was the all wheel drive version of the gas i ever sold in Europe?
I'd love to get my hands on the front axle from one of those and put a series motor on it (perhaps along with some spacers and negative offset wider wheels to approximate the US width and put down enough rubber to take advantage of front axle torque.
That would be quite the i-sleeper!

 

[PV1]

As good as the RWD i-MiEV goes in snow, an AWD ought to be a real tank, go anywhere you please with ease :lol: . Don't forget the inner fender plastic, ours are clearly marked 2WD.

 

[jray3]

Don't forget the inner fender plastic, ours are clearly marked 2WD.

But our fender liners also appear to include a panel marked for cutout in the AWD version.

 

[Kodawari]

Hello Everyone. I recently had my 2012 i in for annual service. The dealer (who has sold the most of these in this area, Washingotn DC Metro area) mentioned that he inspects the transmission fluid as well. I said that the manual did not indicate replacemet for quite some time (since mine has only 10K in mileage). He stated he has noticed transmission fluid wearing out faster possibly due to the small size cases and heat being generated by the CV transmission.
I did see a sample of the fluid and it was not the typical ATF color anymore but getting dark. I went ahead and replaced it.
May make sense to have this fluid inspected on your annual checks and replace if needed. Much cheaper than having a transmission replaced. The fluid change ran about $65.

 

[wmcbrine]

The dealer (who has sold the most of these in this area, Washingotn DC Metro area)

If I may ask, was this King, in Gaithersburg? Or who? I'm curious to know who has the most local expertise.

 

[JoeS]

He stated he has noticed transmission fluid wearing out faster possibly due to the small size cases and heat being generated by the CV transmission.

Clue that perhaps the dealer is clueless? :twisted: Sorry, but isn't our "transmission" merely a differential? Maybe a case can be made that the fluid gets contaminated as the internal parts wear. About 20 years ago I recall being shocked when I once went into a (non-Mitsu) dealer's back room and saw signs all over the place reminding the employees to always recommend items and procedures associated with the work the customer is having done. Upselling borders on the illegal, IMO.

I did see a sample of the fluid and it was not the typical ATF color anymore but getting dark.

Here is a discussion of automatic transmission fluid, pointing out that color is not necessarily an indicator of condition:
http://www.agcoauto.com/content/news/p2_articleid/141

I went ahead and replaced it. May make sense to have this fluid inspected on your annual checks and replace if needed. Much cheaper than having a transmission replaced. The fluid change ran about $65.

Can't hurt, as long as they're squeaky clean performing this fluid change and properly torque the plug and don't put in more than 0.79qt of the specified DIAMOND ATF SP III.

The i-MiEV manual Regular Maintenance Schedule does not show changing the transmission oil all the way out to 240months (300,000 miles); however, the Severe Maintenance Schedule does show replacement at every 30,000 miles. Reading our manual's definition of Severe Maintenance Schedule, I have to wonder how many of us qualify? What does driving on dusty, rough, muddy, or salt-spread roads, police or taxi commercial operation, extended use of brakes while driving, driving in sandy areas, or more than 50% operation in heavy city traffic during hot weather have to do with transmission oil "wear"? Apologies for my cynicism.

Is there a test that a dealer does to determine the fluid's "condition"? The only way I know is to have a lab analysis performed, for example, http://www.blackstone-labs.com/transmission.php

Edited once.

 

[Don]

He stated he has noticed transmission fluid wearing out faster possibly due to the small size cases and heat being generated by the CV transmission.

Clue that perhaps the dealer is clueless? :twisted: Sorry, but isn't our "transmission" merely a differential?

Yes, coupled with a fixed gear reduction of about 7 to 1. No shifting or ratio changes of any kind

Actually, there's much, much less heat generated in our gearbox than any automotive trans I can think of - CVT's do get warm . . . . but we don't have one!! Whatever you do, don't let *that guy* do any 'work' on your car!!

Don

 

[jray3]

Indeed, no CVT here, but I was amazed when I saw a diagram- our gearbox is much more complex than I expected, not just a differential. Many gears and shafts are used to accomplish that fixed ratio and differential action.

 

[kiev]

It looks like just a 2-pass gearbox with differential on the output. Typically you can get a maximum of about a 4:1 ratio in one gear pass--it's difficult to get much more than that. So for example take a 2:1 gear plus another pass at 3.5:1 and you end up with 7:1, because the gear ratios multiply each pass.

The spiral-cut gears might be a problem later in life as they exert an axial force on the layshaft that must be carried by the end bearings. In this picture it looks like they are using single-row deep groove radial ball bearings, which can not carry much axial load. A better solution would have some sort of angular contact bearing (preloaded pair) designed to carry both radial loads and the axial loads in both directions. The axial load changes direction depending upon whether you are driving the gear in motor mode or the gear is back-driven by the wheels when coasting in regen. Tesla uses this same design and more than a few owners have reported to having gearbox 'milling' noises and replacement under warranty, some have failed several times in the same car at under 50k miles, Edmunds had one for a year and replaced their gearbox at least twice. Of course tesla's massive torque doesn't help the situation, but eventually a radial bearing will wear out when used in this sort of application.

Yellow is the input shaft, magenta is the final output holding the diff.

 

[Don]

It looks like just a 2-pass gearbox with differential on the output. Typically you can get a maximum of about a 4:1 ratio in one gear pass--it's difficult to get much more than that. So for example take a 3:1 gear plus another pass at 4:1 and you end up with 7:1.

I think you must be using the 'new math' :lol:

If you chain a 3:1 reduction to a 4:1 reduction what you end up with is a 12:1 reduction, not 7:1

A 10,000 RPM motor run through a 3:1 gives you 3,333 RPM and then it you run that through a 4:1 you get 833.33 RPM, the same as you'd get with a 12:1 reduction. A 7:1 would give you 1,428.57 RPM

Don

 

[kiev]

lol 'the new miev math' maybe--i corrected the example gear ratios...