Thread: Gearbox getting hot...

And if you did not have your IIDtool plugged in you would have not have noted the temps and none the wiser - the car's systems didn't tell you that you had a system so one can assume you dont - yet.

Too much information can be dangerous but then it can alert you to possible future issues.

Until the car fault systems advise you have an issue then I would be tempted to leave it.

Garry

what gearbox?

I know the GM5 in my old TD6 would go up to about 96 when working hard and back down to 88/89 as soon as the load reduced or the TC locked up - didn't make any difference towing.

I'd definitely be investigating.

The attitude that there's no issue if there's no lights is a fantasy. The same TD6 said everything was fine when the engine thermostat was stuck - only noticeable difference to me was a jump in fuel usage, temp gauge read perfect, diagnostic kit showed coolant temp wasn't getting above 60deg. I'm pretty sure driving a diesel for the rest of it's life at 55deg while it's pouring extra fuel in an attempt to warm up would not be good for it. Sure it won't blow up immediately and leave me stranded but it would be limiting it's life at best.

Either it is running hotter than it likes, or a sensor? Either way I'd be tracking it down.

Originally Posted by 101RRS

And if you did not have your IIDtool plugged in you would have not have noted the temps and none the wiser - the car's systems didn't tell you that you had a system so one can assume you dont - yet.

Too much information can be dangerous but then it can alert you to possible future issues.

Until the car fault systems advise you have an issue then I would be tempted to leave it.

Garry

hahaha - 100% what i was thinking while i was typing this post

But... Yes, true.

It's an M62 V8 - 5 speed 5HP24...

After seeing the temp go down (annoyed too because i was already part way home ), i started wondering if it was just "sticky" and therefore it'll be fine from now...?

You are better raising your concerns than not - after you have a range of opinions as you are starting to receive you can have a better idea on what the way ahead should be - along with my advice to watch and see - I would keep the IIdtool connected and see if there is consistently high temps or if it was just a one off and then decide if you need to start pulling things apart.

Good luck with it.

Garry

Originally Posted by 101RRS

You are better raising your concerns than not - after you have a range of opinions as you are starting to receive you can have a better idea on what the way ahead should be - along with my advice to watch and see - I would keep the IIdtool connected and see if there is consistently high temps or if it was just a one off and then decide if you need to start pulling things apart.

Good luck with it.

Garry

I finally found a post from RRPhil which said that overheat is 140deg C - so while i was getting towards that, it never got there.

Whether that was the gearbox working it's own magic cooling strategy, or it was the thermostat, etc... no idea... Hence the question.

I don't often go for drives this long, but I want to start and while i'm by myself breaking down is fine, but the family won't be impressed when they are with me

Alright, left car since this morning... It's 13 deg outside.

Used IIDTool to check temps!

Radiator coolant temp: 18 c
Coolant temp: 24.8 c
Gearbox oil: 38 c

So clearly there's an issue with the temp sensor. It may not be +20 c all the time, but certainly at this temp it is.

Today I checked the temp of the pipes to the tranny cooler (using an IR, not laser one) and they registered 116 on the way there and 116 on the way back... Maybe the variance is less at 100deg, but it's definitely wildly out at room temp!

From other posts I've found they suggest the lower radiator gets clogged... This car has a Behr in it from 2008 (apparently the plastic one blew up after 5 years)... So I guess it could be clogged at the bottom and it's possibly worth draining the coolant and checking the lower radiator... I'm not keen to mess with things that work, but preventative maintenance is always better than failure!

Hi NUTTER,

I had the exact same issue on my 03 M62. It was a blocked tranny cooler.

Easy to check. Drain your coolant and pop out the cooler from the plastic mount on the bottom of the radiator by sliding back the retaining clip and pulling it out. the oil lines can stay connected. Get your garden hose and stick it in each side of the cooler and see if you have a blockage. I'll bet you do.

On mine I had a full blockage so a coolant system flush wasn't going to help. I used a bit of coolant system acid cleaner in a squirty bottle to clean out mine until the new one arrived.

I also checked my Tranny thermostat and housing when I was checking for the issue with mine but it was fine and pretty clean inside.

When you get your new cooler I'll bet the oil line release tabs will brittle and you won't be able to get the oil lines off. A real PITA. To get mine off I used one of fuel line release plastic tool kits you get from supercheap but the tab that goes into the fitting is too short so you just grind down the outer part by about 5mm and it works a treat.

I also had the radiator out when I was doing my timing chains and although it was changed in 2016 there was quite a bit of brown flaky crap that came out of it when I flushed it. So I would recommend a good coolant system flush when you are putting it all back together.



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Hey guys,

Ive just replaced my tranny cooler on my 05 M62. It was definitely blocked, however there are inconsistencies with the temp readout via the IIDTool.

My tool reads the temp as + 15 deg over what it actually is for the 'Oil Temperature' under the 'Transmission' values. I have validated this at the temp sensor area from the underside of the car on the pan with a laser thermo.

I now base all my temps on the 'Gearbox Temperature' under the 'TBOX-Transfer Case' values.

I asked RRPhil about this directly one time and he said yes they are inconsistent and asked what i was worried about, no codes have been thrown. I thought it was obvious!!

My values run from 90-100deg depending on what I'm doing, and i have validated the flow rates for the radiator etc via the LR bulletin to verify my radiator is not blocked LTB000080 attached.

You can check the temp sensor by hooking pins into the cable where it plugs into the TCM in the engine bay box (values attached), these came back on the money for me.

Im also halfway done converting to electric thermo fans (and have an 88 deg thermostat installed) and can say after running around with no clutch fan, just the aux working, the temps do stay quite hot in the gearbox, so i would check your fan clutch to see if it is engaging when hot. This could lead to inadequate cooling when loaded and driving slow.

Heres my rig after sitting for a day. Impossible for the Oil temp to be that high.

IMG_7250.jpgIMG_7249.jpg