Hi all,

I find this forum very useful and informative and was hoping for some help, so here goes my first 2 question for all to ponder :cool: :

1. 92 magna: how does the power transfer to the wheels in the auto version? I know manuals have clutches, but how do autos do it? I've heard of a torque transfer box but can someone please elaborate what the mechanism is between the gearbox and wheels?

2. I have a 92 TR (surprise!) and it's done 186k. When going uphill or when on the highway over 80 km, the power transfers in a really strange way. All of a sudden it becomes a little intermittent and uneven, like the connection between the gearbox and the wheels is not full (very much like a manual clutch slip). We've checked the wheel balances, type pressures etc and changed the auto transmision fluid (no flush yet). Has anyone come across this or knows what the problem could be? Any thoughts would be highly appreciated. Very hard to describe feeling but it almost feels like the car rocks a bit forward and backward when on a highway over 80km or when going up a really steep hill (ie when gearbox is under high load). Also is it just me or does the third gear on autos have a really similar ratio to the second gear, almost the same ??!!

Regards,

Hi all,

I find this forum very useful and informative and was hoping for some help, so here goes my first 2 question for all to ponder :cool: :

1. 92 magna: how does the power transfer to the wheels in the auto version? I know manuals have clutches, but how do autos do it? I've heard of a torque transfer box but can someone please elaborate what the mechanism is between the gearbox and wheels?

2. I have a 92 TR (surprise!) and it's done 186k. When going uphill or when on the highway over 80 km, the power transfers in a really strange way. All of a sudden it becomes a little intermittent and uneven, like the connection between the gearbox and the wheels is not full (very much like a manual clutch slip). We've checked the wheel balances, type pressures etc and changed the auto transmision fluid (no flush yet). Has anyone come across this or knows what the problem could be? Any thoughts would be highly appreciated. Very hard to describe feeling but it almost feels like the car rocks a bit forward and backward when on a highway over 80km or when going up a really steep hill (ie when gearbox is under high load). Also is it just me or does the third gear on autos have a really similar ratio to the second gear, almost the same ??!!

Regards,

Welcome to the club.

In autos, the engine is connected to the trans by a torque converter. At lower speeds,
below 70ish, the engine spins up one turbine in the TC which in turn spins up the viscous
fluid in it and then in turn the viscous fluid spins up the other turbine which is connected
to the transmission. At speeds above 70is, the fluid in the TC escapes the centre bit
causing the two turbine plates to mesh, giving better economy. This is the TC locking up.
When the car is under load, say, at 80km/hr, you start accelerating or start going up hill,
the TC unlocks. If the load increases, the trans will also go down a gear or two. I think
your problem is that the TC is locking and unlocking while going up a hill. Does the rev
change? When the TC locks, the rev drops a few hundred and vise versa.

Have a look at howstuffworks (http://www.aussiemagna.com/forums/www.howstuffworks.com)for info on TC and auto tx. They have very nice animation.

I see, what you mention could be the issue. Does changing the tranny fluid also change the TC's fluid? if not, could that be the cause, that the fluid in the TC might be getting old? ( I don't think we've changed it since we bought it at 120k.)

thanks...

i also had a problem like you are describing except my fuel filter was rooted and when under load or accelerating the car would surge very badly.

may be something to look at. if you take the car to a competent mechanic they can at least tell you what the problem may be. it is kinda hard to take guesses from what you have posted but if it is the box that is at fault then i agree with buff - overdrive.

hi all,

Good ideas here, esp the one about the overdrive slipping, but if that were the case perhaps it shouldnt do that on the tough uphills. It may be possible that the engine is cutting out slightly under load or something, although under hard acceleration is fine... its only when maintaining high speed or putting system under load on uphills only that the power seems to disengage from wheels slightly and then get back ... its very cryptic.it really feels like the gearbox and transaxle, esp since the issue developed after my dad drove the car with trailer full of stuff without turning o/d off or using a/t mode (as much as i told him to)...

if its the o/d clutch how do you fix it? where is the o/d clutch?

thanks heaps, getting really good ideas on this... :)

I see see its a 6 cyl

Its an old school 2.6 92 model :) with 186 on the clock.

amazing how much torque this engine has....

hi all,

Good ideas here, esp the one about the overdrive slipping, but if that were the case perhaps it shouldnt do that on the tough uphills. It may be possible that the engine is cutting out slightly under load or something, although under hard acceleration is fine... its only when maintaining high speed or putting system under load on uphills only that the power seems to disengage from wheels slightly and then get back ... its very cryptic.it really feels like the gearbox and transaxle, esp since the issue developed after my dad drove the car with trailer full of stuff without turning o/d off or using a/t mode (as much as i told him to)...

if its the o/d clutch how do you fix it? where is the o/d clutch?

thanks heaps, getting really good ideas on this... :)

The O/D clutch is in the AT box. The OD is just a fancy name for gears with ratios less
than 1.

Gears with ratios greater than or equal to 1:1 are said to be reduction gears and gears with
ratios less than 1:1 are said to be overdrive gears. Thus, your 1st to 3rd gears are
reduction gears and your fourth is an overdrive gear. 5Spd autos have four reduction
gears and 1 overdrive gear. Some 6sp autos have four reduction gears and 2 overdrive
gears. OD gears are for fuel effeciency and not for torque required for pulling heavy loads.

Take the car to an auto trans specialist and let them perform a proper service. Normal
service centres won't touch the internals of an auto box, all they do is change the oil and
filter.

very much the same as the tr 4 cyl auto box


different part numbers and gasket
just a better diff ratio to get to it the overdrive is at the end plate you can undo
and if lucky will just have to buy the friction plate kit and seals and refit


typical end clutch parts ...half way down the posts
http://www.mitsubishiclubaustralia.com/forums/viewtopic.php?t=824

Hi all,

I find this forum very useful and informative and was hoping for some help, so here goes my first 2 question for all to ponder :cool: :

1. 92 magna: how does the power transfer to the wheels in the auto version? I know manuals have clutches, but how do autos do it? I've heard of a torque transfer box but can someone please elaborate what the mechanism is between the gearbox and wheels?

2. I have a 92 TR (surprise!) and it's done 186k. When going uphill or when on the highway over 80 km, the power transfers in a really strange way. All of a sudden it becomes a little intermittent and uneven, like the connection between the gearbox and the wheels is not full (very much like a manual clutch slip). We've checked the wheel balances, type pressures etc and changed the auto transmision fluid (no flush yet). Has anyone come across this or knows what the problem could be? Any thoughts would be highly appreciated. Very hard to describe feeling but it almost feels like the car rocks a bit forward and backward when on a highway over 80km or when going up a really steep hill (ie when gearbox is under high load). Also is it just me or does the third gear on autos have a really similar ratio to the second gear, almost the same ??!!

Regards,

1. Make sure you use the correct auto trans fluid.
Definitely NOT DEXRON.
Get the Mitsubishi Fluid.

2. Check the fluid level is correct.
It must be checked with the engine running and in NEUTRAL.
Checking in PARK will give incorrect readings.

Isn't park a neutral gear?

Isn't park a neutral gear?

Info from an auto transmission specialist.....

With Magna auto boxes, there is a difference.
There is a valve somewhere that is closed when in PARK and open when in NEUTRAL.
This causes different fluid level readings.
Owners manual states must be checked in NEUTRAL.

How weird, learn something new everyday.

hi all,

Good ideas here, esp the one about the overdrive slipping, but if that were the case perhaps it shouldnt do that on the tough uphills. It may be possible that the engine is cutting out slightly under load or something, although under hard acceleration is fine... its only when maintaining high speed or putting system under load on uphills only that the power seems to disengage from wheels slightly and then get back ... its very cryptic.it really feels like the gearbox and transaxle, esp since the issue developed after my dad drove the car with trailer full of stuff without turning o/d off or using a/t mode (as much as i told him to)...

if its the o/d clutch how do you fix it? where is the o/d clutch?

thanks heaps, getting really good ideas on this... :)

Maybe when your Dad used the car for towing, he overheated the transmission fluid and it lost its viscosity. This may have only been a short trip for the towing, but it still could have happened. Manufacturers recommend installing a extra cooling system which attaches to the radiator, so to cool the transmission fluid and prevent from overheating when doing a lot of towing.

Hopefully it's not the same problem as mine.
Car would let me run for a few hundred metres in "L" then would just sit there rolling and reving but won't lock into gear.

Could be your ECU or the tranny belts slipping. Chuck had a similar problem and it was his ECU.

Still waiting to see what the problem is. Car had to get towed to the workshop.