Engine racing when changing up to 3rd - auto box

[themightyo]

After getting the new gearbox in and sorting out the no-drive in 1st problem with a new ecu, I've noticed a tendency for the gearbox to select 3rd quite late. I think it did it before I swapped ecus as well. It only happens when accelerating hard, so as a result I've resigned myself to driving like a granny until it gets sorted. Does it in both auto and tiptronic. Basically the revs will go up further than for other gear changes, sometimes as far as the limiter, and the box will have a couple of tries before 3rd finally "catches". When driving conservatively there are no issues whatsoever.

When the box was replaced, the guys doing it didn't have any Amsoil ATF so stuck in some Dextron III (/duh ) just to make sure everything was working correctly. About a week later, I took round some Amsoil to get it filled properly. Could my symptoms be caused by the Dextron ATF? Am I right in thinking that about half the ATF remains in the box when you change it out so it'll need a proper flush to get all the Dextron out, or is there something more sinister happening?

Cheers,
Andy

[elnevio]

If only 5/6 litres of Amsoil was used, then yes, it will not have been fully flushed of Dexron III.

I wouldn't have thought it would be causing the weird 3rd thing though. Might be worth just trying another autobox ECU as a test - otherwise (and maybe Peter Thomson might have an idea here) could this be a sticky solenoid?

[themightyo]

I took 15 litres of Amsoil round, and there's a full 5L tub and a bit more left over.

[Gly]

the dextron will have ruined or is ruining your gearbox clutch packs,
it should never be used in a mitsi box, (unless you use a hfm additive but thats another topic altogether)

if it wasnt flushed out it will still be causing issues.

get it done properly and hope that its only that causing the issue,
and it hasnt ****ed the gearbox already

[themightyo]

That's what I thought. I told the guys to wait until I got round with some Amsoil as well... :(

It's been in the car about 5 weeks altogether, and I've done about 500 miles in that time. Is this long/far enough to bugger the clutch packs?

[psbarham]

500 miles won't have any detrimental effect on the box.

also what was the part number of the g/box ecu you removed from the car?

[themightyo]

500 miles won't have any detrimental effect on the box.

also what was the part number of the g/box ecu you removed from the car?

Thank goodness for that.

I'll let you know the part number on Thursday. I'm offshore until then, and the one I changed out is sat in the passenger footwell. It was a f/l one if that helps.

[themightyo]

In fact, does anyone know much about my car. The guy I got it from says it's a bit special, but I don't see how. It's R725 XKR, p/f/l, and Pete got it from some guy down in Ipswich. It's had an engine swap at some point in its life, has a f/l engine ecu, and before I changed the gearbox it had a f/l box in as well.

[bradc]

It doesn't sound special or unique, but putting up some pics will help. In the mean time, you need to get amsoil only in the gearbox and then reset the ECU by disconnecting the battery for 5 minutes or more.

[Kieran]

I'm not convinced that Amsoil will help here; it's 50/50 anyway (okay that's not ideal), but I can't see how the clutch packs would have been buggered in 500 miles by Dexron III.

Hang on... I've just had a lightbulb moment.... :idea2:

You said it now has a facelift engine, right? So does that mean the TCL is deleted?

You see, when shifting, the Gearbox sends a 'Torque reduction signal' to the engine ECU to help smooth the shift (it backs off engine power). What I'm thinking is with a (I presume?) Pre-Facelift box in there, it's sending this signal to the engine ECU, BUT - on the facelifted (IE Non-TCL) engine ECUs, the signal is carried on a different ECU pin.

When no 'Torque Reduction Signal' is detected by the ECU, it defaults to NOT reducing engine output... Given that it can manage a shift okay on part throttle, I'm wondering if the lack of torque reduction is causing such massive flares?

What's the 3--->4 and 4---->5 shift like if you've got your foot hard down (in Tip and in D)?

[Gly]

by new gear box what do mean,

fully rebuilt?
or just a 2nd hand replacement,

was the gearbox looked over at all, could be broken/damaged wave springs?

if second hand, it may have been on the way out already, and the dextron may have just made it wosre quicker,

IMO wrong oil is no good, no matter how long its been in there,
it will have done some damage, it may not show immediately but it will do damage,

the wrong oil will glaze and make the clutch packs, slip and shudder,

[themightyo]

I'm not convinced that Amsoil will help here; it's 50/50 anyway (okay that's not ideal), but I can't see how the clutch packs would have been buggered in 500 miles by Dexron III.

Hang on... I've just had a lightbulb moment.... :idea2:

You said it now has a facelift engine, right? So does that mean the TCL is deleted?

You see, when shifting, the Gearbox sends a 'Torque reduction signal' to the engine ECU to help smooth the shift (it backs off engine power). What I'm thinking is with a (I presume?) Pre-Facelift box in there, it's sending this signal to the engine ECU, BUT - on the facelifted (IE Non-TCL) engine ECUs, the signal is carried on a different ECU pin.

When no 'Torque Reduction Signal' is detected by the ECU, it defaults to NOT reducing engine output... Given that it can manage a shift okay on part throttle, I'm wondering if the lack of torque reduction is causing such massive flares?

What's the 3--->4 and 4---->5 shift like if you've got your foot hard down (in Tip and in D)?

Dunno about facelift engine. Just a facelift engine ECU.
From 2nd to 3rd under hard acceleration is the only time I have a problem - happens in both auto and tiptronic. All other gears are fine.

[themightyo]

Maybe someone has a pfl engine ECU I can try?

[peter thomson]

Sorry missed this one. We have mixed ecus in Keiths car and it displays a similar problem but we have tried a post facelift ecu with no change to how the box changes. The box had been flushed probably about 3 times with amsoil in the hope that it would sort it but to no avail. It still drives well enough and we have another box to go in so have not taken this any further but Kieran's post could well be on the money

We have a facelift with a prefacelift box. Facelift engine ecu and preface autobox ecu

[themightyo]

also what was the part number of the g/box ecu you removed from the car?

Hey mate. Part number is... erm... there are a couple:

MR367177
G1T18285 H1 8114

[keithatport]

yep, as Peter says this is the same as mine but the flaring and hesitation in changing gears happens to some extent in all the gears. If it is linked to the TCL then Ben at Eurospec has solved this problem with the Vipec but not sure if we can apply the same fix with standard ecu's

[psbarham]

Hey mate. Part number is... erm... there are a couple:

MR367177
G1T18285 H1 8114

cheers for that, that the same part number as the original pfl owc box. hey ho the search continues

[amsoil]

The fluid is unlikely to be the culprit here, I like Kieran’s ideas (I usually do).
Even just Dex 3 should give a passable change, although a little harsh. Its the harshness that produces the localised heat that will eventually break down the fluid. Once this starts to occur then the problem escalates. As can be imagined slipping and heat in the plates are the boxes enemy.
Amsoil may be the best but no fluid is a mechanic in a bottle. I would be looking elsewhere to find what the problem is.

[peter thomson]

Completely agree Don as it didn't help us but the box is still alive so the amsoil is doing it's job in keith's VR4

[themightyo]

What's a Vipec? Some fancy aftermarket ECU? Are they prohibitively expensive?
Did it in mine yesterday changing up from 3rd to 4th, which is new.

[Nick Mann]

Very fancy aftermarket ECU. Search this site for it - Eurospec supply and Ben is the man who can. If I was in the market for an ECU that's the one I would be trying to afford!

[themightyo]

Well the box just seemed to sort itself out today. No more dodgy changes from 2nd to 3rd, or any other gears. Dunno what happened, just started working fine on my way home tonight. Could it have been a sticky solenoid as previously suggested?

Only thing now is that changing from Drive to Reverse (but not the other way round) occasionally results in a pretty severe jerk.

At least I don't need to splash out on some crazy ECU anyway.

[Davezj]

you may find the dodgy gear changes were just the ECU relearning the shift point of your auto box.
shift points/type are reset to defaults when ecu is reset when battery disconnected. this can make the shift very jerky and slippy for a good few miles after reconnection, i know mine does when i reset my A/T ecu. the dexron III would not have helped with the slippage though.
Some times the the A/T ecu will just snap back in to a good mode after a while, how many miles have you done since the ECU was last reset.

The only way to really check this is to reset your A/T ecu again, but once the shift point are back most people a reluctant to take the chance.

This is why i fitted an Engine ECU reset switch so i don't have to rest the A/T ecu every time i want to clear the engine error codes. i couldn't go through the learning process on the A/T ecu each time.
sorry a bit off topic.

[amsoil]

I would hazard a guess that the varnish and other associated cr*p in the box are being broken down very slowly as you only have a 1/2 mix of Amsoil in there. Yes the ECU's fussy logic will also be smoothing things out but theres nothing like a good detergent based ATF to clean things out properly. You however have just a mix of it so it would take longer. If right then the reverse thing will eventually clear up but it will take time.
Just my 2 p's worth

[themightyo]

Well whatever Dextron was in there has been diluted with some more Amsoil than I thought cos there's actually only about 2L left of the 15L I had. The other 5L is engine oil...

Since the new gearbox it's done about 1200 miles so an ATF flush probably wouldn't go amiss, just to be sure it's all Amsoil.

[Davezj]

Firstly, you need to do is join the club and become a fully paid up member.

Secondly, get you order in with DON amsoil at www.performanceoils.com

Thirdly, realise the members discount you get at performance oils is worth more on the amsoil ATF than you pay for 1 years membership it is a win, win, win, win, situation. Don't forget the ATF filter if it is an external one. your could be full of cack now.

if you are going to do another flush then make sure it done properly. As you will be a member, print out the procedure from the articles section and give it to the person doing the ATF change and watch them while he/she does it. or do it yourself for complete satisfaction.

side note, i do think Amsoil ATF is very good stuff and i use it in my auto box. but the slip from second to third gear is exactly what my box does after a reset, but my auto box still slipps very very slightly when completely cold and only for the first couple of 2nd to 3rd changes. i should probably put an order in for some more amsoil for myself.

[amsoil]

Ok lets get some perspective here.
The Mitsi auto box is a fantastic very high spec unit. It can handle great abuse and handle much more power than most peps on the forum can accept. It appears to be limited by the strength of some components such as output stubs etc. It also relies on the AYC /diff unit that has its own foibles. Everyone's auto box has had many may years of use (abuse?) with several owners who have been unlikely to have had the correct ATF put in the box. Given all this it is a real wonder to me that these auto boxes have so very few problems. This is simply a testament to the original design and spec of the unit.
That said here we all are 10 years or so on. The auto box in general may have had 1 or 2 fluid changes with more than likely the wrong fluid. It will have taken wear as a consequence and have an amount of cr*p inside it. On average I doubt if it has ever had a filter change; yet it has survived.
Amsoil produce a fluid more than suitable for this box, this is were I came in a number of years ago, because of the probs peeps were having. This ATF works. Not only does it work but it will clean the inside of your box and remove a decade of cr*p from abuse. A new filter is certainly a good idea (we do not sell them and you are on your own here) With Amsoil ATF when the detergents have fully done their job , not instantly but over time, and with the aid of a reset fuzzy logic ECU, you will have effectively maximised your package.... You may still have a little jolt in a given gear change or slip at some point but this is wear and damage that it is not in the power of any fluid to sort, no oil / ATF is a mechanic in a bottle nor can it put back metal to valves or material to friction plates. You will have achieved the best you can without going to hours of ag and thousands in costs. Use the best. Forget the rest. You will find the Amsoil ATF will actually last so much longer that it will become the cheap option And not many things in life are like that.
Of course all of this is IMHO, and I am open to any ideas anyone has.

[elnevio]

My gearbox ATF was changed nearly two years and 22,000 miles ago, out went the ? ATF that was definitely on its way to brown.

Since then, it has seen four track sessions at Castle Combe (two of which were when it was completely standard, so no gearbox cooler), multiple hard launches up the strip at Santa Pod, seven laps of the Nurburgring and a trickle of occasional (ab)use in normal driving :whistle:. On top of that, a hot couple of weeks driving to and from France last August.

No problems at all. The Amsoil ATF that went in is still red. I have only added about half a litre of new stuff when I fitted the gearbox cooler (last May, about 8,000 miles ago).

Nick Mann is able, IIRC, to confirm that he has seen SP-III completely toasted in just one track session at Combe.