Auto transmission lock... Electric?????

[Mike v.t.s]

Hi all, reet ive just spoken to an auto box specailist about my auto lock not working unless im towing summert or i drive it hard down the motoway, my way of thinking (along with help on here) is that the oil wanted changing as it had gon "sticky" inbetween the plates... well the transmission specailist told me that the auto lock is operated by the temp of the engine, so when the engine is upto temp it does it automaticaly, so is he right is there a temp sender for this on the head??? if so which sender is it?? many thanks people.

 

[goonarmy]

you mean when the gear box locks and stops the "clutch" slipping? I thought it was governed by speed, the hand book on me classic sed 54mph IIRC.

 

[Datatek]

Torque converter lock up is governed by speed, load and throttle opening. On the flat with a light throttle opening, lock occurs at around 54mph. Engine temperature does seem to affect gear changes though in that it holds third for longer when cold on mine.

 

[Mike v.t.s]

Torque converter lock up is governed by speed, load and throttle opening. On the flat with a light throttle opening, lock occurs at around 54mph. Engine temperature does seem to affect gear changes though in that it holds third for longer when cold on mine.

Sorry for the late reply (laptop had a fight with a glass of water... and lost) yes mine does sem to lock up when ive been drivving on motoway for 20 mins or longer but it does lock from 50mph onwards, i defanatly do have to work it harder to make it lock sometimes, i have noticed if im towing my trailer tnt or anything else it seems to lock up alot sooner, and the other day it couldnt make its mind up on what it was doing, it would semi lock then unlock etc etc and thats with light pressure on the pedal and on the flat, just cant seem to understand it and cant find any1 that will do a "trans flush" i.e disconnect a pipe from gearbox cooler and pump new oil in as the old oil flys out whilst engine is running... dammmmm it lol.

 

[jamesmartin]

just changing oil will flush system enough presuming yours isnt contaminated with metal particles or clutch plate material,dynamic flushing is only necessary in that case.lock up is goverened by ecu using speed ,throttle position etc ,it is done with a clutch pack in t/c which locks engine to gear box rather than been transfered betwwen rotors by oil,use dextron 2 which is high detergent to free any valves that may stick in block,it is possible for this clutch to fail (slip) as others though rarer but shoul be evident with no positive lock up

 

[jt_armstrong]

What are you guys talking about? I've never heard about auto box lock up before. Can someone explain it in simple terms.
Many thanks.

 

[jamesmartin]

when cruising auto box has clutch inside to give direct drive from engine to gear box so revs of engine correspond with road speed as with manual gear box before this point drive between engine and gear box is transfered by high pressure oil between rotors so no direct drive so the amount of torque transfered is variable and never a 100 % depending on engine revs ,so you can transfer very little and creep or standstill in gear hence name torque convertor,and why autos are more thirsty than manuals before lock up or direct drive

 

[Mike v.t.s]

just changing oil will flush system enough presuming yours isnt contaminated with metal particles or clutch plate material,dynamic flushing is only necessary in that case.lock up is goverened by ecu using speed ,throttle position etc ,it is done with a clutch pack in t/c which locks engine to gear box rather than been transfered betwwen rotors by oil,use dextron 2 which is high detergent to free any valves that may stick in block,it is possible for this clutch to fail (slip) as others though rarer but shoul be evident with no positive lock up

Hi, thanks for the info, is the dextron oil compatible with the standard stuff, i mean can it be mixed with the normal ATF thats allready in the box?? i no that il have to change it twice as you never get it all out or is there a set procedure. thanks (auto boxs are not my thing... anything else is no problem, unless its a P38)

 

[ovalandrover]

just changing oil will flush system enough presuming yours isnt contaminated with metal particles or clutch plate material,dynamic flushing is only necessary in that case.lock up is goverened by ecu using speed ,throttle position etc ,it is done with a clutch pack in t/c which locks engine to gear box rather than been transfered betwwen rotors by oil,use dextron 2 which is high detergent to free any valves that may stick in block,it is possible for this clutch to fail (slip) as others though rarer but shoul be evident with no positive lock up

My manual says Dextron 3 not 2

 

[jamesmartin]

dexron 2 is normal atf ,it wont matter they have run on dexron 2 for 20 years with no lube probs,the box is still basically the same as early boxs with a couple of extra clutch plates but same material,beefed up gear carriers and one way clutch,they are compatible and you dont need to change all for it to flush internal parts but use dexron 3 if you want ,when you get some on dirty hands youll see how it cleans,it wont effect clutch packs but parts of high precision fit,valves and one way clutches,dexron 3 is just later version of dexron 2 ,these boxes never suffered from poor lubrication or faults to do with oil not been up to the job,its rare even in old boxes to find much cotamination unless something has failed due to torque stress rather than lubrication

 

[goonarmy]

What are you guys talking about? I've never heard about auto box lock up before. Can someone explain it in simple terms.
Many thanks.

in very basic terms (and possibly incorrect) the drive from a auto is similar to a constantly slipping clutch. The slipping clutch is the torque converter. when this locks it doesnt slip, however this only happens at higher road speed. It feels like a fith gear on thzf 4 speed box and is more efficient giving better mpg, everybody love better mpg

 

[jt_armstrong]

in very basic terms (and possibly incorrect) the drive from a auto is similar to a constantly slipping clutch. The slipping clutch is the torque converter. when this locks it doesnt slip, however this only happens at higher road speed. It feels like a fith gear on thzf 4 speed box and is more efficient giving better mpg, everybody love better mpg

Thanks goon & james. I understand now. Never really thought about before but makes perfect sense.

 

[Mike v.t.s]

I feel like a reeet noooooooob, i checked the gearbox oil when stone cold and there was non on the stick!!! it took almost a liter to put it where it should be which i didnt understand... then i figured it out... when i checked it last id allready been out and must not of let it cool down enuf, now it seems the torque conv lock might be working normal again as its locked on twice just on the small A roads, its NEVER done that before, just cant work out how its working as i thort the gearbox oil and torque converter oil are seperate???????????

 

[Mike v.t.s]

I must apologise, i do have 2 post running and they have turned into the same thing even tho the original question wasnt, but the answer and the root of the problem are the same, my fault chaps but thanks!!! soddin great site on ere.

 

[Datatek]

Torque convertor share the auto box oil, if the oil is low it's one of the first things to suffer.