Do I Need A Transmission Cooler

[ChrisB]

So i drove from up to Lake Mountain today and took the kids to the snow.

Between Healsville and Marysville i put the stick into Manual and discovered that the transmission would not shift up or down on demand and the display just sat on "4"

In "D" mode it was still working perfectly and shifting automatically. It just would not shift manually.

I pulled over in Marysville and it was working in Manual again. (without even having to re-set the ignition)

I'm thinking it was some kind of safety feature on the transmission computer and perhaps the transmission was getting hot due to all the hill climbing and low gear work.

Down hill all the way home and manual shifts were perfect.

Has anyone else experienced this issue?

Should i get a transmission cooler and if so how much, where from and how to?

Car is an M35 ARX

Cheers in advance and hope to see you all soon on the next cruise.

Chris

Edited July 2, 2012 by ChrisB

[Commsman]

Yes, get a trans cooler. Costs about $100 & available from auto stores everywhere & E-bay etc. Simple to fit. Just look first at how much room you have & get one to suit. It doesn't need to be very big to be effective.

Edited July 2, 2012 by Commsman

[KiwiRS4T]

If the fluid looks dirty/burnt get some new fully synthetic fluid (you'll need 10-12 litres).

[pbk1776]

I'm getting The same experience Mostly long drives. done the oil tranny change, it helps.

If I get one - I might get one from eBay without the hoses and fittings, might get them from earls just to make sure that I can mount it where suitable

[XRATED]

Don't bother with earls fittings and 'performance hose'.... the lines arn't under that much pressure. PWR make some great trans coolers in most usable sizes. They're available from repco etc - the whole lot should come in under $120 including more hose if needed. The PWR kit comes with hose clamps and mounting fittings etc. Make sure you buy trans hose if you need to buy extra.

I'd sugest plumbing it in after the/any factory coolers (not sure on your m35, you may have a small air to air cooler or a warmer/cooler as part of the radiator) and using a cooler core that has slightly larger inlet/outlet fittings than the stock cooler (just reduces any pressure loss across the core).

I'd also change the trans fluid too...

This is what I did with my C34, it works a treat with my modified auto trans.

Cheers

Justin

[theferris]

I learnt the hard way in how valuable an oil cooler is the other day in my Jeep. Going over a big set of hills, just started blowing smoke. Didnt loose any function in the box to begin with. Now it doesnt have 4th and reverse is almost gone. It did something similar to yours about a year back, thought it was a computer problem, swapped it out and didnt have a problem until the gearbox blew its load everywhere.

[ChrisB]

Guys,

Great Information thanks.

The Transmission was flushed and filled with Mattic S a few months ago.

I will check the colour but hope its OK.

When i get a transmission cooler i hope it will only need topping up.

When plumbing in the cooler, should i put it in series with the radiator or disconnect the trans hoses from the radiator?

[Commsman]

I put mine in series with the radiator so that the warm oil flows thru the a/m cooler then onto the radiator. This means the trans should get up to temp quicker as the oil is warmed by the radiator before it flows back in. It also means on really hot days it will take some load off the radiator by cooling the trans fluid a bit before it gets there.

Running it independant of the radiator will work OK as well (no heat load on the radiator at all), but may take a little longer to get up to good operating temp.

[scotty nm35]

I fitted one of these thermostats inline with my trans cooler, it allows the transmission to warm up to operating temp before flowing through the cooler, and will limit the amount of cold 'issues' you will have when you just plumb it in.

http://www.ebay.com.au/itm/LONG-OIL-THERMOSTAT-COLD-CLIMATES-OC-708-4739-/370626344630?pt=Motors_Car_Truck_Parts_Accessories&hash=item564b0d36b6#ht_820wt_1159

The hoses may be a different size, I had to use adapters for the hoses, but it works well.

[andy65b]

++++100 on the in line thermostat. So simple but effictive.

[slippylotion]

I use a Long Tru Cool trans cooler as it has a built in bypass at the top of the cooler for cold fluid then as the fluid warms up it's directed through the cooler core to cool.

[Mr 20Valve]

I put mine in series with the radiator so that the warm oil flows thru the a/m cooler then onto the radiator. This means the trans should get up to temp quicker as the oil is warmed by the radiator before it flows back in. It also means on really hot days it will take some load off the radiator by cooling the trans fluid a bit before it gets there.

Do you remember which hose between the gearbox & radiator was which?

I was planning on hooking up my trans cooler the exact same way...

[PN-Mad]

From memory. If you are lying under the car looking towards the rear.

Top is pressurised flow from the trans, bottom is the return to the trans. That's the hard lines that end just near the sump. To make sure, just pull the bottom line off the hard line, and put it in a clean 1 litre bottle. Get someone to turn the car on for only 2 or 3 seconds. Should pump out 500 ml or so. You can add the fluid back in via the dipstick.

[theferris]

On a semi related note has anyone towed anything relativity heavy with their Stag? Thinking maybe rally car sized.

[bigkevracer]

I think Duncan does with his C34? Wouldn't try that with an M35 though.

[PN-Mad]

On a semi related note has anyone towed anything relativity heavy with their Stag? Thinking maybe rally car sized.

With a NA c34? Towing a rally car? Might be a bit over zealous there.

[Daleo]

With a NA c34? Towing a rally car? Might be a bit over zealous there.

So 750kg of trailer, and 1200kg of car; how early will you be leaving for an event? Any hills along the way?

Not my pick for a tow car; that's for sure.

[theferris]

With a NA c34? Towing a rally car? Might be a bit over zealous there.

So 750kg of trailer, and 1200kg of car; how early will you be leaving for an event? Any hills along the way?

Not my pick for a tow car; that's for sure.

Ahh you know, figured it weighed in pretty similar to a V6 Holden and the Straight 6 Cherokee it wouldnt be too bad.

And as for time it would be day before and NZ doesnt have many flat roads.

Is more of a long term possibility then needing to go to an event next week.

I still have to rebuild and sell my Cherokee and move to a more car friendly place before I consider it.

[Daleo]

Ahh you know, figured it weighed in pretty similar to a V6 Holden and the Straight 6 Cherokee it wouldnt be too bad.

And as for time it would be day before and NZ doesnt have many flat roads.

Is more of a long term possibility then needing to go to an event next week.

I still have to rebuild and sell my Cherokee and move to a more car friendly place before I consider it.

Yeah, weight of the Stagea is probably similar to a V6 Holden; the torque from a NA RB25 however, no where near similar.

You'll be giving the clutch a hiding just to get it moving.

RB25/30 with a turbo? Now you're talking.

[lilcrash]

on the towing note - ive towed a few heavy loads (64 besser bricks + trailer, car trailer + car), and my car(c34 rs4s) tows beautifully, only issue ive had was clutch slippage reversing the car trailer of a steep driveway, only slipped for a second before all 4 wheels started spinning. but definatly wouldnt recommend with an na.