ATF oil cooler by-pass valve

[Sancho]

Yes but that's monitored by engine temp not gearbox the only temp sensor on the box warns of fluid overheating .

So once the engine's up to temperature it tells the gearbox it's OK to switch up. With a separate ATF cooler (particularly if it's oversized), the engine sensor may say it's fine to switch up when in fact the ATF is still cold.

I see where you're coming from, but for the sake of 25 quid and an hour's fiddling I would personally prefer to make sure my fluid gets up to operating temperature as soon as possible and certainly before the engine management thinks that it is.

The difference is going to be marginal, but we are talking about driving around Scandinavia here.

[Apache]

£25 for an hours fiddling is a bargain!

I'd rather do it with a solenoid valve, so I get to decide. its just cos I'm a geek like that.

[steved]

Auto oil is specially formulated to maintain it viscosity over a huge range of temperatures from -40 to over 100 degrees c the battery will pack up and the diesel will wax before you need to worry about the auto oil.

[Sancho]

Auto oil is specially formulated to maintain it viscosity over a huge range of temperatures from -40 to over 100 degrees c the battery will pack up and the diesel will wax before you need to worry about the auto oil.

I'm genuinely curious now - why prevent the box from switching up until it's reached the correct operating temperature then?

[steved]

Its more to get the engine up to operating temp quickly.

[nordic venture]

now this is getting interesting.

if what steved says is correct then a bypass isn't needed. but i always though that optimum operating temperature was around 70-80 deg. if you were to put a large cooler and drive around in say minus 5, surely that would lower the temp below this?

[Apache]

Both probably right.

The auto fluid will 'work' between -40 and +100 degrees, but it is optimum at 70 to 80 degrees.

Does no harm to keep it in that optimum band as much as possible does it?

[nordic venture]

Both probably right.

The auto fluid will 'work' between -40 and +100 degrees, but it is optimum at 70 to 80 degrees.

Does no harm to keep it in that optimum band as much as possible does it?

indeed. so a by-pass isn't a waste of money then as it'll open and close as temperature dictates, and with the cooler, help to keep the oil temperature as near to optimum as possible

[Sancho]

indeed. so a by-pass isn't a waste of money then as it'll open and close as temperature dictates, and with the cooler, help to keep the oil temperature as near to optimum as possible

I think the point is that it's not necessary to keep your truck running and you won't damage it by not having one, but that you will get faster, smoother shifts if you have it at the 'right' temperature.

[POPEYE]

As Nordic said this is getting interesting, i got a BMW cooler which i've yet to fit so wondering if i should fit one of these switches/valves?

[MattF]

Of course the fluid will retain it's characteristics to a degree at extremes. It'd be sod all use otherwise. There is an optimal operating temperature, however. Screw your box prematurely or spend thirty quid on a valve. Simple choice.

[MattF]

First generic link picked from Google:
http://www.roadandtrack.com/article....rticle_id=3090

There's shedloads more indepth tech info around if you wish to check. The one above was used for brevity only.

[KERRSURF]

Hello and welcome Nordic.

can you post pics of the setup once you decide, are you still using the original cooler as well?

[blackpoolsparks]

if you want to get really techy you could fit a temp sensor and add a temp gauge on the dash.

[nordic venture]

Hello and welcome Nordic.

can you post pics of the setup once you decide, are you still using the original cooler as well?

no, i by-passed the original in rad cooler completely. (scared of it leaking)