NEW D-MAX /MUX /COLORADO FORUM

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 Post subject: Transmission lock up
PostPosted: Sun Oct 01, 2017 10:10 am 
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Joined: Wed Feb 26, 2014 8:24 am
Posts: 8
Question for all you mechanical experts on this page, my Colorado a 2011 RC Auto 97000km has developed a sensation that when you pull up after a good long run (At least 1 hour at highway speeds) it feels as if you have a flat tyre, or have transmission wind up when you go to pull off again, don't know what it is, no signs of oil leaks or anything, once it cools down there is no signs of anything. Maybe limited slip diff locking up? Don't know, any help appreciated.
Cheers Ian.


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 Post subject: Re: Transmission lock up
PostPosted: Sun Oct 01, 2017 11:28 am 
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Joined: Sat Oct 12, 2013 5:36 pm
Posts: 1581
Ian
The only time you would feel a limited diff retardation is when you try and turn. going straight ahead it behaves exactly like and open diff.

If you pull up after a long hot run, the intercooler will immediately get heat soak happening as heat rises upwards from the engine. If it gets hot it isn't qute acting as an intercooler and so power will be down with less oxygen getting to the cylinders. as you drive, forward motion will again drive air DOWN through the IC and cool the turbo air and power should be normal.

If you stop and the engine cools down, then it will be back to normal. I have a 2011 Dmax.

Perhaps get your fan clutch checked for operation as it may be not driving at low/hot speed and not cooling the engine and bay down.
Ok while driving as forward air passes through rad and into IC too.

Does your vehicle have the fuel cooler under the lhs passenger feet, is there on a 2011 Dmax. If it is clogged and full of crap then the fuel will be hot going to the engine instead of normal temp. Your vehicle has a plastic tank and therefore less fuel cooling, so it has the fuel cooler to reduce fuel temp arriving at the inj pump.
After a run the tank will be lower and therefore less mass of fuel to heat up so the fuel may be elevated in temp, which means less energy injected with the fuel being hot. Fuel flow is 7psi and around 37L/Hour at that pressure, normal fuel system flow does heat the fuel.

Is your fuel usage increased? The free play of the master cylinder to booster may be holding brake pressure in the lines while engine bay is hot. Is there sufficient brake pedal push rod free play.
Is there a dragging brake. Have you jacked it up to check wheel free rotation/movement rears won't revolve much with an LSD though.

How long ago were the engine valves adjusted, not check like dealers do by listening to what they can't hear, but REAL adjustment? The engine valves amy be closed up and require clearance checked/adjusted. If serviced by Oldhen they probalby haven't been touched since new. If borderline that can affect hot power output markedly.
Just a few things to check.


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 Post subject: Re: Transmission lock up
PostPosted: Mon Oct 02, 2017 8:02 am 
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Joined: Wed Feb 26, 2014 8:24 am
Posts: 8
Thanks for the reply mydmax, think you might be right on the money with the possibility of a dragging brake, last service the hand brake was adjusted fairly tightly, on with only two clicks, everything else checks out OK so will chase this down this week and let you know. Once again thanks.


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 Post subject: Re: Transmission lock up
PostPosted: Mon Oct 02, 2017 8:59 am 
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Joined: Sat Oct 12, 2013 5:36 pm
Posts: 1581
Who ever set the 2 clicks position can't tell if the 2 click amount is free running or holding the brakes on a slight amount. Unless they then lift rear wheels and chekc for free rotationI would think 2 clicks WILL BE insufficient slack/free play. I cannot have 2 clicks on my 2011 Dmax. It does hold brakes too close at that point.
2 clicks is only flex in the components which are already applied.

Get dealer to supply a new set of drums and shoes so they can learn to adjust properly. $$$$ are a great teacher to some individuals lacking finesse.


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 Post subject: Re: Transmission lock up
PostPosted: Sat Oct 21, 2017 1:30 pm 
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Joined: Wed Feb 26, 2014 8:24 am
Posts: 8
Had it back to my Holden Dealer who have diagnosed the problem as the Diff locking up, they dropped the oil and sent it away for testing to make sere that oil was actually a LS oil (They had done the last service when it was changed) this came back as being to specification. They refilled with a higher spec LS oil and also used a additive (Don't know what, and they are not prepared to say other than it is from Shell special lubricants). Anyhow I have not had any problems since, service manager says it is not a unheard of problem especially in vehicles that have not had a hard life as far off road work where LS diff has been working


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 Post subject: Re: Transmission lock up
PostPosted: Sun Oct 22, 2017 5:16 pm 
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Joined: Sat Oct 12, 2013 5:36 pm
Posts: 1581
Ian.gonzo
The dealer is telling you porkies. What about all the vehicles which are driven normally and do not have a problem. Everytime you drive it, unless going straight all the time, ie, no corneres ever, the LSD plates are continually moving in relation to each other. I can't fathom the little use theory the dealer is sprouting.

They serviced it and the tested oil was correct, that is only hearsay from a dealer. You do not know what oil they put in at service time and they aren’t going to tell you or admit to it either.
To add further questionable disputable doubt, he won’t tell you what SECRET Shell lubricant they used in the diff. What a load of old crock. The Shell lubrication telephone number should readily tell you what is used and any variations on their oil use in LSd diffs. Hardly a secret to be guarded by a dealer. If he isn't open and honest with you he must have something to hide. I wonder what that could be?

A higher spec LSD oil makes it grip more.
If the diff clutch plates were grabbing, can happen, and it was happening to the extent you mention, the turning circle would be destroyed and one rear wheel would be screaming it's tread at every turn or corner.

PS. I have found Holden dealers NOT changing diff oils in RA7 and Colorado's of that age even after 120,000km, still the original diff oil in there. What has your dealer actually done. Arre the paint seals on filler and drain plugs actually broken?

Normal gear oil is Extreme Pressure gear oil and it causes LSD's to slip because the plates can't get rid of the oil film between the plates and so they slip.
LSD oil is formulated to allow the shearing of the oil film molecules so the clutch plates can grip. There are additives available to add to oil for LSD use.


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 Post subject: Re: Transmission lock up
PostPosted: Mon May 21, 2018 1:58 pm 
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Joined: Wed Feb 26, 2014 8:24 am
Posts: 8
Hi Mydmax, have been able to find out what Holden put in my diff, is a Penrite product called "Limslip Additive", have had no further problems since it was put in there. Service advisor told me what it was when I was called in for a check on how it was performing. sample of oil was taken for analysis which came back OK. Will continue to monitor at no charge.


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