Patrol 4x4 - Nissan Patrol Forum banner

1 - 11 of 11 Posts

·
Registered
nissan
Joined
·
60 Posts
Discussion Starter · #1 ·
Hi guys and Gals,
I was just wondering how hard it is to fit an oil cooler to a Manual gear box?
I have a 88' SWB GQ thats running 35's and i notice on Long hiway runs, or sand work my gear box get REALLY warm...... SO i was thinking about fitting a oil cooler to try help keep the oil at good working temp.......

So what i was wondering is has anyone done it before and could put some pic up of there set up, and did they have to fit an inline pump, or would the temp difference be enough to keep a good flow going thru the system?

Cheers


Gordo
 

·
Registered
Joined
·
3,955 Posts
I was looking at doing this also.
You can run 140 oil in them if they are always hot, just make sure it's GL-4.

My thoughts were to do it all in the PTO blanking plate. You can see a bump in the plate to provide clearance for a gear, With the right shaped replacement cover plate this could work as a pump if the gear is turning the right way. You will need a pump of some sort.
Theres some good info in a book called Prepare To Win by Carroll Smith.

You could get large aluminium mud collector (heatsink) and make a new PTO cover.

Another alternative is to make a heat exchanger to go in the PTO plate and pre-heat/cool it using the engine's cooling system and use the high temp 140 grade oil.

None of which seems to be worth the effort until I start experiencing problems with gearbox bearings and gears overheating. You can get a second hand gearbox for a few hundred bucks. I know people with _very_ healthy 350 chevs and the like in front of stock gearboxes, they race them at high speed for hundreds of kilometres. The only things you need to look out for is stripping the spline out of 5th or snapping the input shaft, neither of which will be prevented by cooling.

I've got an oil temp gauge I'll put into the box through the PTO plate and I'll see how the temperature changes with use before I do anthing.
 

·
Registered
Joined
·
2,837 Posts
someone told me one of the ford rangers have an oil cooler system for the manual gearbox. no idea if built in pump or external.
i would just tap into gearbox or even use the drain and filler plugs, connect to pump and to oil cooler. should be able to rig a mechanical pump to V belts. plenty of racing crowds have external oil pumps. no idea on electric tho.
 

·
Registered
Joined
·
3,955 Posts
external oil pumps on race engines are to scavenge engine oil out of the sump and send it back to the tank, what they call a dry sump system. not cheap.
occasionally they do add an extra layer to the back of the pump and use it for gearbox oil.

I wouldnt use the drain plug as a connection point, too easy to smash it off.
 

·
naturally asthmatic
Joined
·
4,387 Posts
GQ manual boxes always seem hot. I understand it is a design issue which runs the heat from the engine bay back along the box. The easiest fix, if you are so concerned about it is to run a good synthetic GL4 gear oil. I went synthetic for extreme cold and being tired of dealing with a notchy box with sub zero weather until the gear oil got warm. A heavier weight oil is not always the solution. For example, Western Star trucks run a 50W gear oil in their transmissions that have a high viscosity heat rating.
 

·
Registered
Joined
·
3,955 Posts
^^ that sounds like a better option. I'll be doing that myself I think.
FYI I had a manual front wheel drive car that ran automatic transmission fluid in the transaxle (including the diff). I actually tried to break that gearbox (to find the weakest link because I was considering turboing it) but couldn't break the damn thing.
 

·
Banned
nissan
Joined
·
201 Posts
Just because it "feels" warm doesnt mean that there will be a detrimental effect on it's lifespan. One could consider that adding an external cooling system where there is no real problem would be a backwards step in risk and reliability.
 

·
Registered
Joined
·
3,955 Posts
Agreed, I know a few vehicles with 400 and even 500 horsepower motors in front of standard boxes for endurance racing and I dont think any of them run coolers.

I'm putting an oil temp gauge in mine to see what it does before I do anything.
 

·
Learned the hard way - RD28t out TD42 in
Joined
·
4,415 Posts
You need to measure the temp before doing this. Cold oil is worse than hot oil - just so long as the hot is not too hot.
 

·
Registered
nissan
Joined
·
622 Posts
I switched to synthetic GL4 and removed the skid plate. The combination of the two things dropped the heat temp down a lot. I barely feel it at the ebrake now.
 

·
Registered
Joined
·
3,955 Posts
You need to measure the temp before doing this. Cold oil is worse than hot oil - just so long as the hot is not too hot.
Perhaps a heat exchanger connected to the heater circuit in place of the normal PTO plate would be a good idea then.
Warm your oil up at first... then cool it if it's getting hot.. It wouldnt be perfect but it should keep it below 120 degrees.
 
1 - 11 of 11 Posts
Top