Transmission Issues?

Nissan Navara Forum

Help Support Nissan Navara Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Browncoat

Member
Joined
Jul 23, 2017
Messages
3
Reaction score
0
Location
Australia
Hi guys,
I recently bought a second hand 2012 STX 550 with 116k on clock from a dealer. I still have 2 months or 3k on warranty.

I've been hearing a noise that sounds like it is coming from the transmission mainly more so when it warms up. While driving in any gear if I feather the throttle between 1500-2000 revs or so I hear what sounds like a rubbing noise not too dissimilar to a brake shoe dragging.

Also I went out on the sand last weekend for a test run and after a while I could smell a cooked oil type smell, I popped the bonnet and could see and hear big bubbles popping in the water overflow tank. Engine was running fine engine temp was fine(didn't waver). I can see 2 oil lines going into the bottom of the radiator and am thinking there must be some sort of internal transmission cooler? So i'm wondering if it is likely there is an issue with the tranny getting hot and further heating radiator water?

Is it likely the 2 issues I have described are related?

Anyone experienced similar or have any suggestions for me?
 
Welcome to the forum.

You are correct, there is a transmission cooler in the radiator. Some people (like myself) have fitted an external transmission cooler - but that's to prevent cross-contamination of the coolant/transmission fluids and to improve the cooling of the transmission (we tow every now and then).

Excessive transmission heat shouldn't cause bubbling in the radiator overflow - I would think that's more likely to be gas entering the coolant, and that's usually from a head gasket.

Easy way to check: get a compression test done. If there's any significant variation between cylinders you'll know the head gasket on one side is damaged.

There are ways to test the radiator for exhaust gases but the compression test will pretty much nail it and even tell you which side of the engine the problem is on.
 
Thanks Old.Tony,

I had thought a leaking head gasket would be there all the time? these bubbles only occurred the one time while driving on the sand and were accompanied by the burning oil smell. Engine temp unaffected.

Any thoughts on the "brake shoe dragging" type noise I hear from around the transmission?
 
Oh it does depend on how the leak is caused, when cold components haven't expanded and when hot they have - it changes things.

It would be a good idea to check the tranny oil. If it's milky you know you've got a problem. Oil will float to the top of the coolant so should be visible in the top of the radiator, although the crooked neck of the filler makes it hard to see - you could check the overflow bottle, some should have made its way in there if there were any.

Otherwise, the compression test is the cheapest and fastest way to rule out a serious problem.
 
Looking into the overflow bottle I can see a small amount of white/brown froth around the edges at the coolant level. The transmission oil itself is not contaminated though it is a dirty dark brown.
 

Latest posts

Back
Top