D6n harsh transmission shifting from reverse to forward?

[Rusty#1]

Hi all,

1st post on here ,

We have a 2007 d6n that shifts very hard (thud) from reverse to forward, it's fine when cold and 1 in 10 times fine when hot,finning suspected power train accumulater so I bit the bullet and did that, still the same, oil in tranny and finals is clean as a whistle, and the tranny has been calibrated, any ideas where to look next? I should add it's been like it since I've owned it and not got any worse (400hrs) but it does need sorting

Many thanks

 

[Cmark]

I would suggest connecting ET and looking at what the transmission temperature sensor is reading and if it corresponds to the actual transmission temp.

 

[ih100]

What oil are you running?

 

[Rusty#1]

Thanks both for the reply,

About 3 months ago it had a transmission temp sender, it was throwing up a error, been fine since

Also running cat spec sae30w,

 

[Nige]

Please give some more details about the oil. "Cat spec" doesn't exactly mean a lot. Also there is no such thing as SAE30W in TO-4 powertrain oil which is Cat spec.
Thinking out loud does the 6N have the same feature as other newer generation machines that the transmission oil grade can be programmed using ET..?

 

[Cmark]

Thanks both for the reply,

About 3 months ago it had a transmission temp sender, it was throwing up a error, been fine since

Can you define "fine"? Far too vague.

What you have (or perceive to have) is what's called in Cat speak a modulation problem. Modulation being the rate over time at which a pressure increases (or decreases) to engage (or disengage) a clutch. The machine relies on various things to control the modulation, one being the tranny oil temperature. If the calibrations have been properly carried out, I stand by my previous advice.

 

[Nige]

Also regarding the transmission temp sensor, what was the fault at the time and what was the action taken to fix the fault..? In my experience this type of thing does not go away on its own.

I would also suspect the transmission temp sensor has a part to play in all this because you point out that the transmission modulates fine when the oil is cold but not when it is at normal operating temperature. The input from the temperature sensor is what sends a signal to the priority valve and there is a status change between a detected transmission temperature of above or below 40DegC. This could have a bearing on your problem.

 

[Rusty#1]

Ha I feel like a lamb in a lions den

Sorry I got it wrong it's not sae30 it's 30w to4 spec from a well respected local supplier


As regards the trans temp sender by fine I mean no errors since they fitted the sendor, finnings diagnosed the sender issue (warning lights and codes) and fitted a new one and calibrated the tranny, so surely they would have seen if the temperature's didn't correspond?! As they charge a hefty call out fee i will need to wait until I need them out again to double double check that the temperatures are all reading as they should,

Thanks for the input, another 10 hours on her clock today, I will update if I ever get to the bottom of it

 

[ih100]

Nige, Cat do do a 30 weight TDTO, not quite the same as TO, but it is an option for a 6N transmission. Personally in the UK I prefer TDTO 10. It's a rare day you get over the upper ambient temperature here.

 

[Nige]

Ha I feel like a lamb in a lions den

Sorry I got it wrong it's not sae30 it's 30w to4 spec from a well respected local supplier.

As regards the trans temp sender by fine I mean no errors since they fitted the sendor, finnings diagnosed the sender issue (warning lights and codes) and fitted a new one and calibrated the tranny, so surely they would have seen if the temperature's didn't correspond?! As they charge a hefty call out fee i will need to wait until I need them out again to double double check that the temperatures are all reading as they should.

Don't feel hard about it. In order to give (hopefully) good advice we need clear information to base it on.......

While I think about it, post a Serial Number so we know what we're looking at. There are about 20 different models of D6N kicking around so it helps to know exactly what you're dealing with.

A "well-respected local supplier"...... Hmmmmm, I'm from UK and have never heard of them, other than as a supplier of hydraulic hose & fittings. Neither can I find a spec sheet for that oil on t'interweb neither which sets my alarm bells ringing big style.....especially considering the fact that there is no such thing as an SAE30W TO-4. Do you have a spec sheet for the oil..? As someone on here mentioned a while ago there is a big difference between a lubricant that "meets" a specification and one that is "recommended for use" where such-and-such specification is required. I'm getting a feeling that what you are putting in your machine falls into the second category, and TBH "recommended for" means jack schitt as far as I'm concerned.
First thing I would do is at the next PM interval where the oil & filter has to be changed is to throw some (in order of preference) Cat SAE30 TDTO, Mobiltrans SAE30 TO-4, or Shell Spirax S4 SAE30 TO-4 into it. you're going to be changing the oil anyway so at worst it will be only a few quid extra.
Are you using Cat power train filters or "will fit"..? If the latter use a genuine Cat filter with one of the above oils at the next PM.
I've said this before and I'll say it again. Good quality oil & filters are the cheapest and best insurance policy you will ever buy for your machine.

Regarding the transmission temperature, can you check what it shows when you crank up cold in the morning and what it gets to when the tractor is up to normal operating temperature and post the results here please. Also when you post the results mention what the ambient temperature is/was. Don't bank on a dealer tech noticing that the temperature signal from the sensor was actually correct, all he's looking for is that the Diagnostic Code that was there before has now gone away .......... hence the question what the cold & warm temp readings are. I'm assuming the tractor doesn't work 24 hours, just a day shift..?

To IH. Cat SAE30 TDTO is the "preferred" oil for the 6N transmission, any SAE30 oil meeting TO-4 specification is classed as "acceptable" for ambients between 0 and 35DegC. To me that would be fine. I'd only go for an SAE10W TO-4 in places where the ambient temperature got significantly below zero on a regular basis throughout the year and apart from possibly the far North of Scotland I can't think of anywhere else in the UK that qualifies.

 

[Rusty#1]

Don't feel hard about it. In order to give (hopefully) good advice we need clear information to base it on.......

While I think about it, post a Serial Number so we know what we're looking at. There are about 20 different models of D6N kicking around so it helps to know exactly what you're dealing with.

A "well-respected local supplier"...... Hmmmmm, I'm from UK and have never heard of them, other than as a supplier of hydraulic hose & fittings. Neither can I find a spec sheet for that oil on t'interweb neither which sets my alarm bells ringing big style.....especially considering the fact that there is no such thing as an SAE30W TO-4. Do you have a spec sheet for the oil..? As someone on here mentioned a while ago there is a big difference between a lubricant that "meets" a specification and one that is "recommended for use" where such-and-such specification is required. I'm getting a feeling that what you are putting in your machine falls into the second category, and TBH "recommended for" means jack schitt as far as I'm concerned.
First thing I would do is at the next PM interval where the oil & filter has to be changed is to throw some (in order of preference) Cat SAE30 TDTO, Mobiltrans SAE30 TO-4, or Shell Spirax S4 SAE30 TO-4 into it. you're going to be changing the oil anyway so at worst it will be only a few quid extra.
Are you using Cat power train filters or "will fit"..? If the latter use a genuine Cat filter with one of the above oils at the next PM.
I've said this before and I'll say it again. Good quality oil & filters are the cheapest and best insurance policy you will ever buy for your machine.

Regarding the transmission temperature, can you check what it shows when you crank up cold in the morning and what it gets to when the tractor is up to normal operating temperature and post the results here please. Also when you post the results mention what the ambient temperature is/was. Don't bank on a dealer tech noticing that the temperature signal from the sensor was actually correct, all he's looking for is that the Diagnostic Code that was there before has now gone away .......... hence the question what the cold & warm temp readings are. I'm assuming the tractor doesn't work 24 hours, just a day shift..?

To IH. Cat SAE30 TDTO is the "preferred" oil for the 6N transmission, any SAE30 oil meeting TO-4 specification is classed as "acceptable" for ambients between 0 and 35DegC. To me that would be fine. I'd only go for an SAE10W TO-4 in places where the ambient temperature got significantly below zero on a regular basis throughout the year and apart from possibly the far North of Scotland I can't think of anywhere else in the UK that qualifies.

Thank you, I will certainly look into genuine oil next time, yes I did use genuine filters,

I assume i'll need the man with the laptop out again to tell us what the exact trans temp is reading?

Yes it just does a day shift 7-5 the trans temp gauge never ever goes above half way

Sn is djy00128

This dozer stuff is new to me, I usually look after my fleet of 3 John deeres and 1 scania myself but not knowing the in's and out's of the dozer yet means I have to call on the dealer which is a pita

 

[Rusty#1]

What interval would you recommend for a transmission oil change? It's done 400hr since I did it

 

[Nige]

What interval would you recommend for a transmission oil change? It's done 400hr since I did it

The only reason I mentioned the oil is simply to rule it out as a possible cause of the problem. Oil &filter change is every 1000 hours or 6 months of operation, whichever comes first, is what the manual says. I would imagine you're on the 6 months rather than 1000 hours if the tractor only works a day shift.

Sorry, I forgot you don't have the all-singing, all-dancing monitor system where you can see the exact temperature in degrees. You only have the quad gauge. To see what happens with the transmission temperature, try a stall test. When the machine is at operating temperature it in 3rd gear and hold it on the service brake. Raise the RPM up as far as it will go and hold it there. Watch the transmission temperature gauge. You should be able to watch it going up and in less than 60 seconds it ought to be in the red. At that point slip the transmission into neutral and keep the engine RPM up. The temperature should fall back to "normal" within seconds.

Another thought crossed my mind. How long has the operator who's running this tractor been on the machine and does he use the decelerator for directional shifts F->R & R->F..? The reason I ask is that when shifting F->R at the end of a push usually the tractor is stopped, or almost stopped. Then you reverse back for the next push and can be going at quite a lick when the time comes to change direction again. Shifting R->F at the point without using the decelerator and/or a touch of brake can give what to some might appear to be a harsh shift but is actually the tractor responding normally to a directional shift made in less than ideal conditions. I know they call these transmissions powershifts, but that doesn't mean you should make directional shifts with them at full power....

 

[LDK]

Is it FTC (fingertip control) or a differential steer tractor.
I have experienced that harsh/jolting/banging directional shifting on D5 and D 6 M/N models but only on FTC tractors. However I decelerated/braked made little or no difference to the condition.
On a few occasions it was sorted via a laptop, other times I had to suffer it till my contract was over and moved on.

 

[Rusty#1]

It's a diff steer tractor, I've spent a good few days on it myself and tried shifting under various different conditions, still the same, also to answer the question yes the decelerater is always used, the machine works on a stock pile pushing up woodchips so is often working at a fair gradient I wonder if that's why it seems harsh, granted a 6r with a big blade would be better for the job but we had to start somewhere and the tidy little 6n came up for sale locally and seems to do the job very well

My driver reports that the accumulater they fitted has actually solved one problem...it was slow to take up reverse when cold ( fine when warmed up ) and he says it's as it should be now, so at least it's not been a total waste of £

She'a done just over 10k hrs btw, also while I'm on here...would anyone be able to advise on how a 963 tracked shovel would perform working on a stock pile? I'm thinking one would be handy to work in conjunction with the dozer on the stockpile

 

[Nige]

Thanks for the info. Do the converter stall test and see how the temperature gauge responds then report back.

 

[nicky 68a]

On another topic sort of.......
I have been running a D8R now for a few months,and unlike my other old D8H/K tractors,I am treating the thing with a whole different attitude than my older D8's.
This is in respect to the oil and filters that Nige mentions.
I have allways used Cat filters for 25 years and changed engine at around 200 hours,trannies and finals every year,and hydraulic oil and filters every time it snows on Christmas day!
I tend to use a more basic 15/40 in the motor and 30 in the tranny.
Hydraulic oil that goes in is generally the cheapish stuff.
However ,my fitter has told me to up my game with the D8R.
It gets only genuine Cat oil from Finnings in sealed containers,and Cat filters obviously.
The engine is getting oil at 200 ish hours,tranny is getting filters at 250 hours,oil at 500 hours.
Hydraulic filter is getting filters at 250 hours and oil at 500 hours.
Finals are getting oil at 500 hours.
All Cat oil and filters.
I'm learning hygein and correct Cat oil are the way forward for this D8R.
The old D8's will guzzel anything I feed them without any problems that I'm aware of and are more tolerant to slacker maintenance.
That D8R works awesome so far,but needs treating like a fine women.

 

[nicky 68a]

The operator also sticks 2 shots of grease into the eq bar every 20 ish hours in this sand.No more,no less.I have a clip on end for the grease gun to ensure that eq bar gets the correct amount of grease.