Clutch smell in auto trasmission

zibello
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Clutch smell in auto trasmission

Unread post by zibello » December 29th, 2014, 4:51 am

Hi all,
The other day I was out in a desert area, very mild off roading, low speed, nearly no more effort than on a normal gravel road. The car insistently smelt of a clutch or similar smell. The problem is that my PA challenger is auto. Actually, it was a while that I was not using the 4wd so I thought maybe it was that, Still I cannot entirely understand the smell. All oils should be clean and up to levels as I change them frequently (provided that the dealer does change them when I ask for and he bills me for).
By the way, on my return home, I noticed the gear lever became very sticky, especially selecting from P to R or D and from 1 to L.

Any idea / experience?
G.

Peter Aawen
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Re: Clutch smell in auto trasmission

Unread post by Peter Aawen » December 29th, 2014, 11:59 am

Over-heating auto trans oil can smell a lot like burnt clutch smell.... :( (altho I won't go any further into what the dealer may or may not be doing when they service your vehicle!!)

Running your vehicle on a loose surface without selecting 4WD isn't a good idea - especially if it's an auto!! With any 4WD, by selecting 4WD you will be getting traction from the engine delivered to both ends of the vehicle in order to improve the steering, braking, & handling etc as the drive will be split between the front & rear driveshafts. That's easy enough to do when it's a 'proper' Part Time 4WD, pull the lever or push the button that selects 4H & you've engaged a gear or chain driven link in the transfer case that splits the drive so there is no real chance of there being slip or any disparity of drive sent either way - it just does the 50/50 split (or whatever split their gearing is designed to do) & drives the front driveshaft & the rear driveshaft at the same speed regardless, which is why you don't ever want to run a Part Time 4WD with 4WD selected on a hi-traction surface - it won't turn corners well & you can damage the trans case &/or driveline by trying to force it to accept the different speeds necessary at each end of the vehicle that allow the vehicle driveline to turn/compensate for the differences in road surface.

BUT, it's not quite the same thing for All Wheel Drive vehicles (because they have a centre differential that allows different speeds at each end unless locked) or vehicles with a swish transfer case like the Super Select or one of the other mulit-choice options that are common on many Jeeps & Mitshubishi's with part-time/full time options - cos they also hafta have something that allows the same function as a centre differential built in.... all so that the vehicle can drive each end without breaking while running on hard/hi-traction surfaces by allowing different speeds between the front & rear wheels. Anything with a centre differential simply isn't in (the equivalent of) 4WD UNTIL the centre diff is locked - that's because the centre differentials allow different speed/drive delivery to each end & because that means you are effectively only driving ONE end at any given moment (altho that can change many times each second as the traction under wheels/thru diffs varies...) And to make things worse, that centre diff will always deliver the most drive to the end with the LEAST traction when it's unlocked, even if it has viscous coupling or something else to make it 'share' the drive!!

What that means for you is that when you drive on a loose surface without the trans case in 4H with the centre diff locked, your trans case &/or auto box will be working a whole lot harder than it needs to be due to the drive being sapped by the un-locked centre diff as it spins one end a lot more than the other. When it's an integral part of the transfer case that does that, it will heat the trans fluid rapidly. Sooo, if the driver doesn't understand how their transfer case & centre diff works, it's quite common to find Pajero's & Challenger's (& Toyota's with AWD) especially if they are auto's stuck with little, or in the case of the auto's NO DRIVE on sand or other loose surfaces simply because the driver didn't select a 'Locked Centre Diff' drive option & their centre diff/trans case or their auto has over-heated & either shut down entirely or dropped into 2WD 'Limp Home' mode until the transmission fluid cools off!!

So I'd suggest that's exactly what happened to give you that smell & the sticky gear selection - you drive it with the centre diff unlocked thru your transfer case selection, & that meant the differences in speeds/drive delivery to each end caused the trans fluid &/or the centre diff to overheat!! Simple solution is to remember to LOCK the Centre diff whenever you drive on loose/not hi-traction surfaces. Driving on loose surfaces with the CDL un-locked often will be wearing the Centre Diff &/or the trans/torque converter out quicker than it should, as well as meaning that you will be driving with somewhat less traction, steering, braking, etc than could be available to you if you selected the right gear/range in the hi-tech trans case Mitsubishi spent a lot of $$ on designing & making available for you!!

Basically, if a loosely swung foot can scuff up any loose stuff off the surface you are driving on, then it's going to be better for your vehcile (& therefore your safety & traction) & less expensive to you in the long run if you select a gear/range that locks the centre diff. ;)
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

zibello
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Joined: December 29th, 2014, 12:09 am

Re: Clutch smell in auto trasmission

Unread post by zibello » December 29th, 2014, 12:41 pm

Hi Peter,
Perhaps that is exactly what it happened. Since che surface was so good, I omitted most of the part of the road to engage the 4wd. Next time I'll certainly do. Still, the next day, I was doing some heavier sand, I did engage the 4wd otherwise no go, and had the smell again.
If it is trans oil overheating, shall I now change it as a prudential measure?
I changed trans oil and filter only 2k before.

Timmo
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Re: Clutch smell in auto trasmission

Unread post by Timmo » December 29th, 2014, 12:44 pm

zibello, disregard what has been mentioned about a centre differential. It is irrelevant to you.

Peter, Challengers do not have a centre diff, They are not All Wheel Drive.

Sounds like you have just overheated the auto. Extended low speed sand work will do that, made worse by attempting it in 2wd. The constant slipping of the auto just generates heat and unless you are travelling at a speed where the airflow is sufficient to cool it and the torque converter/trans can "lock up", it will just keep getting hotter. An auxiliary trans cooler is a must have in a Challenger.
Cheers,

Nathan

zibello
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Re: Clutch smell in auto trasmission

Unread post by zibello » December 29th, 2014, 1:12 pm

I see, Nathan, tks. It seems I'm learning the hard way about 4wd. Allow me pls two more questions:
1) My trans oil has now about 2 or 3k kms only: should I change it nonetheless, as the overheating might have deprived it of its lubricating qualities?
2) My car has 90k kms on the clock, bought it 5th hand. Do you think I might still be on time fixing an additional trans oil cooler?
G

Timmo
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Re: Clutch smell in auto trasmission

Unread post by Timmo » December 29th, 2014, 1:29 pm

Pull the trans dipstick and see if it smells "burnt". Cooked trans fluid has a really bad smell about it. If so, change it. If you're not sure, get someone to check for you or change it as a precaution. If you tend to work your car harder than what it would normally be subjected to (ie. Extended sand/off-road work or heavy towing) then maybe a switch to synthetic fluid may be a viable option.
I did it in mine and noticed improvements.

It's never too late to fit an external cooler mate, it might be what saves your trans next time.
Cheers,

Nathan

Peter Aawen
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Re: Clutch smell in auto trasmission

Unread post by Peter Aawen » December 29th, 2014, 1:34 pm

Peter, Challengers do not have a centre diff, They are not All Wheel Drive.
Hmm, I was pretty sure they came with a Super Select 4WD Trans case, or at least a variation of that, to which (if you read my post) all that applies...

But you are right about the trans fluid cooler, it's never too late to fit one! ;)
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

Timmo
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Re: Clutch smell in auto trasmission

Unread post by Timmo » December 29th, 2014, 1:38 pm

They don't have "super select". Wasn't offered on PA Challengers.

The Challenger has what Mitsubishi called "easy select" which is just a plain old transfer case same as every other 4by.
Cheers,

Nathan

zibello
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Re: Clutch smell in auto trasmission

Unread post by zibello » December 29th, 2014, 1:42 pm

I'll do check and also fit an additional cooler.
This will be good especially in summer where we go up to 55 celtius and the sand becomes pretty warm too...
Cheers,
G

Peter Aawen
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Re: Clutch smell in auto trasmission

Unread post by Peter Aawen » December 29th, 2014, 1:47 pm

Ahh well, you learn something new every day!! I've run into a few Challengers with the Super Select (& this problem...) & just assumed that they all had the same trans case! They must've been the newer/upmarket models.... :o
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

Timmo
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Re: Clutch smell in auto trasmission

Unread post by Timmo » December 29th, 2014, 2:15 pm

No PA Challengers were released with Super Select.

Whatever vehicles you're referring to as having a super select transfer, I can guarantee they aren't Australian delivered PA Challengers (which ran from 1998-2006).

Pajero's yes, believe the Delica vans also had it but not the PA Challenger. Not 100% sure of the same era MK Tritons but I believe they missed out on it too.

The later PB Challengers had it as an option I think but they are a totally different vehicle and bear no similarities to their predecessors.
Cheers,

Nathan

zibello
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Joined: December 29th, 2014, 12:09 am

On this long covered issue - Trans temp. gauge

Unread post by zibello » December 29th, 2014, 10:20 pm

Hi, again on this thread of hot transmissions...
I was surfing for a temp. gauge kit and have come across this one on Ebay Australia:
EG01-2 TWIN SENSOR Engine & Transmission Temperature Alarm- digital display

Any feedback? Anyone knows if it's okay? Shall I buy it?Other suggested kits?
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jalopy
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Re: Clutch smell in auto trasmission

Unread post by jalopy » January 5th, 2015, 1:14 pm

http://www.automatictransmission.com.au ... wsId=42067
http://www.automatictransmission.com.au ... wsId=13012

The Wholesale Automatics transmission gauge might be better. In lots of sand and heat the transmission will heat up quickly. From what I gather the temperature light comes on at a bit over 150 degrees. When it gets to 120-130 you should be looking for somewhere to stop and let it cool down.

Scootymad
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Re: Clutch smell in auto trasmission

Unread post by Scootymad » September 17th, 2018, 6:31 pm

Bit old but my PA2 has super select. And I've roasted my trans a couple of times already doing some heavy towing (loaded horse float uphill). But the PA2s got a pretty ordinary transmission and it was well shot to hell and back before we even bought it

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