Mitsubishi Delica Owners Club UK™

[peter_rookie]

hi all,
now having done my first long trip I had about 700km highway to cover.
at 60mph mine sits at around 2800 and 65 around 3000rpm.
Some say 2500 should do.
my OD seems to engage, feels like it.
S1, 1994, 2.8 swb on 30x9.5 15
please share!
cheers
Peter

[Google]

[Deker]

RPM - Looks good to me  

Mine does <= 3,000 RPM at 70 MPH.

Mr D

[peter_rookie]

thank you!
relieved.
I will get a transmission flush next week anyways and hope that volatile reving will stop then. was worried as some claim 2500at that speed, ...

[peter_rookie]

I had my ATF replaced but unfortunately have sourced the wrong filter element so had to refit the old one.
there was no debris visible but guess the filter must have been there for ages.

revs have not changed at all, shifting feels bit strange, couple of days it seemed like a gear got stuck when climbing a hill. black smoke cloud and total loss of power, shifted manually to L and then 2, made it up the hill, was really irritated...

[Lewis]

The ATF filter is inside the Transmission housing, it is not designed as a general service item for changing when you do an oil change.
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[peter_rookie]

I am aware of that Lewis. I am just not happy how the transmission works and considering it being a 1994 model and how bad the old ATF looked I thought (and was recommended by my mechanic friend) to replace the filter. not quite sure if a clogged filter will have effect on the oil pressure inside of the valve body but might be so?

[andyman]

How steep was the hill that you had to change down to L to keep going, or was it on a steep hairpin bend that you had to slow down for? You are correct in thinking that the auto-box should just cope and change down without your intervention. When changing the ATF by draining from the transmission sump, you only get around half of the  fluid out, so you might be advised to drain again, running the shifter through all the gears with the handbrake on hard and wheels chocked, with engine idling, to clear all the hydraulic galleries.
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Andy C L300 Super Exceed - over 100 smiles per gallon!

[Lewis]

If you drain the ATF with the engine running and cycle through the gears, the gearbox will stop working, though the pipes running to the front cooler going through the bottom of the radiator and the air cooler, behind the LH headlamp, will still contain ATF.

Best thing is to drain the ATF, undo the pipe coming down from the air cooler to the return pipe and drain that, then refit and add a couple of litres of ATF, just enough to allow the gearbox to function, run the engine and then cycle through the gears to flush the chambers with fresh ATF.  Then redrain the sump and air cooler and refill to normal level.  That way you change out the maximum amount of ATF.
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Copyright is retained for all my photos. Please don't copy them without asking permission
Do not blindly go where the path may lead you. Go where there is no path and leave a trail that others may follow!
ルイス

[andyman]

Maybe there's a difference between the workings of the L300 and L400 gearboxes. Obviously, with the engine running at idle, the L300's purely hydraulic gearbox (except the O/D switch) opens the operating valves as you move the shifter, allowing most of the fluid to be pumped out. When refilling, it appears to refill and bleed itself by the same method.
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Andy C L300 Super Exceed - over 100 smiles per gallon!

[peter_rookie]

I have now changed the fluid two times as I first sourced the wrong transmission filter.
finally got the right one and fitted it.
the difference in shifting behavior is significant. a clogged filter will not allow for the required operating pressure in the valve body.
still the revs are where they have been and I saw a video on youtube of pistonshack, guy somewhere east of us who fixed an OD issue and got it down to 2300 at 60mph. so strange...

[sir naggedalot]

at 60 on the satnav mine sits at about 2350 or 2300 if I sit behind an artic at 56. Totally gutless but I preferred to go with economy over grunt. Going to have the pump out shortly, so I might tweak it slightly more, then.

[peter_rookie]

interesting, thanks.
still leaves me puzzled.
bigger wheels would mean higher speed at same rpm with smaller ones.
some say not necessarily which I don´t get. either OD engages and TQ closes or not?
S1 auto, 1994 2.8, 2800 rpm at 60

[andyman]

Yes, at 60mph cruise, or even accelerating from there fairly gently (so as not to engage kickdown), the torque converter should be locked, so revs and indicated speed should rise in exact proportion. If the revs increase more than the speed, you may have a worn gear clutch/brake, effectively slipping, like a manual clutch. At lower speeds, up to around 50mph, the torque converter may not lock, so  the engine speed rises quicker than the road speed until the TC locks up.
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Andy C L300 Super Exceed - over 100 smiles per gallon!

[peter_rookie]

thank you also Andy, no, the transmission seems fine, all engaged and locked, no slip.
I do have a Toyota Prado with more or less the same old transmission, three speed+OD, so I am pretty confident I understand how it should behave. that one I have regeared to lower diff ratios and still it runs 2500 for 60 (different animal, I know, but almost same year, three litre diesel turbo, same power output...)
and this leads back to my trouble. why are the revs that high?
where can I start?

[sir naggedalot]

With a GPS to ensure that it's really the speed that you're being told by the speedo, and an external rpm meter to show that it's the correct revs being shown also? I'd check the timing if possible as maybe it's off so yours isn't producing the right power at the specified revs?

[peter_rookie]

compared to GPS and speedo is slightly faster.
timing?
starts on the spot without any hesitation, runs smooth as  a kitten, no smoke....
wouldn't that show some other symptoms?

[sir naggedalot]

timing can be slightly out on a diesel, but still run fine but have a slightly reduced power. Often chains can stretch/wear and this slightly retards the timing so it's not quite getting the full power but still runs well enough not to be noticed. get an egt if you want to advance it a bit extra as while you might get better performance, you run the risk of melting the head 🤯

[sir naggedalot]

Must have been a brain fart as timing isn't going to make any difference once the torque converter locks up to the rpm/speed ratio. The only difference would be time and fuel consumed. Apologies for burgerling your time with a misleading post. 🖐️🤡👍

[peter_rookie]

thanks for restoring order :-)
appreciate your thoughts!

[peter_rookie]

hi All,

I was test driving again, measuring against GPS speed of 100km/h which is 62mph and revs counter showing 2850 maybe 2900.

so, because I still could not figue out why my revs are that high altough everything feels right (OD engaging blabla, accelerating with OD engaged without kick down , no slipping TC)

here some theoretical exercise:

my 4M40 driven S1 L400 sits on 30inch Tyres atm, sorry, I am a metric guy so all data from here in meters...

the circumference of my 30" are 2,3939m
at a speed of 100km/h it turns 696,2 times per minute equals to 1666 meters per minute x 60 minutes = 100 km/h which then makes a distance 100km per hour driven (just as sanity check)

according to data sources my diff gear ratio is 4,875 and the OD has a ratio of 0,705

having 696,2 turns of the wheel considering 4,875 ratio means engine revs 3393,98 times a minute but now the OD ratio needs to be considered on top, meaning 3393,98x0,705 = 2392 revs per minute in OD for 100km/h or 62mph

so, my counter shows almost 500 revs more.
maybe someone has changed the diff ratio? but that must be very very short like 5,91 and this I doubt as the max speed I did once for testing was around 150km/h or 93 mph although I don´t remember the revs but certainly not in the reds

if I was to fit 31" Tyres the revs needed should be 2315 per minute, you can follow that calculation starting from what ever diameter your Tyres have.

my next step is to put an actual crank sensor on it and see what the real rpm says against the reading. you have to start somewhere, right??