Slight engine surge at around 1500 rpm

[Nomad9]

Hi There,
Just aquired a D3, 2005, V6 4.0 petrol, runs fine apart from a very slight engine rev movement around the 1500 rpm mark. As far as I can tell it appears to be in 3rd gear. You can feel it a little bit and the tacho moves accordingly. Out side of that rev range sweet as, rock solid.

I thought it was OK when in cruise, however that idea was scuttled this morning on the way to work, the movement (surge) is less, very slight, but still there.

I'm doing a steal pan conversion and changing the oil in the very near future on the gearbox, this is for me just precautionary if I had this issue or not, just like to know where I am up to with things.

Any ideas? I haven't touched anything as yet, I'm doing an engine oil and filter change at the weekend just to get things to I know where they are at.

Throttle body............. maybe? Dunno, look forward to hearing from people soon, thank you for any assistance rendered.

[winaje]

Sounds like the transmission fluid needs the change, wait and see how it goes after the steel pan conversion and new fluid, hopefully they will do a full flush.

Mine was the original fluid at 310k, had the pan fitted and Nulon SYNATF changed into it. Surge is gone, vehicle runs better. I found that using sport mode reduced the surge until I had the fluid change done.

[jonesy63]

I agree with Will - sounds like the auto needs an ATF change. Good luck.

[Nomad9]

Hi There,
The "they will" is me, I have an affinity for Royal Purple oil for reasons I don't need to go into here. My intention was to use the reccommended Lifeguard 6 oil, I have heard some weird and wonderful tales of people using anything but the recommended oil sometimes with not good results.

I applaud you Will, good to hear a success story, mine has done 190k so a bit behind your 310k. sprt mode, I'll try that...............so it isn't the throttle body then....... Bugger!!!!

I also get a bit nervous when there is the offer of "good luck", thanks Jonesy.

[winaje]

...I have an affinity for Royal Purple oil for reasons I don't need to go into here. My intention was to use the recommended Lifeguard 6 oil, I have heard some weird and wonderful tales of people using anything but the recommended oil sometimes with not good results...

Some will say only use the genuine fluid. Others will say try other things. There are a couple of "proven" fluids that can "replace" the LG6. The info can be found here and on the UK forums. I personally hate being forced to pay exorbitant rates for things, so went with a different fluid.

When changing it, be very aware that the new fluid must be measured by volume when at a temperature of between 35 and 50C. This is so that the correct volume is added, as the fluid expands when hot.

[Nomad9]

Hi Will,
Agree 100 % with your comments and yes I put in a measured volume and have the oil at the right temp, I have done a couple of steel pan conversions prior to doing this one on other D3's. Having a hoist now helps a lot.

I'll have a look and see what I can find, exorbitant price, you are not kidding $38/L + gst, ride on macduff................

[winaje]

Might find the posts from this one on interesting regarding fluids... http://www.aulro.com/afvb/d3-d4-rrs/125041-disco-3-4-automatic-transmission-faq-4.html#post2171530, well the whole thread of course, but that post refers to my experience with the Nulon.

[Epic pooh]

Dirty throttle body is more likely to cause rough / hunting / fragile idle (my v8 experience anyway). But cleaning it and associated sensors (airflow etc) never hurts !!

[Tinman]

I'm with Will, I have changed my transmission oil with Nulon also, the boss who drives it daily reconds it is now like driving a different vehicle with smooth quick changes with much more go. I too had the nervous tacho, now with the oil change tacho back to normal as well as car
Cheers

[jonesy63]

Hey Tinman - how many km have you done with the Nulon ATF?

I think a lot of reluctance to move are the horror stories and no long-term alternatives. Horror stories like mate that put in Penrite Synthetic - at the time they recommnended it to replace ZF LGF6 - only to retract that after his auto blew up!

[Tinman]

Only about 2000 at the moment about to go on a trip to the Flinders in about 3 weeks so will see how it goes. The atf that was changed when the steel pan was fitted only lasted 50,000klm before it started to do the slight shuddering etc, now changed with Nulon it is silky smooth :)

[Nomad9]

Hi Tinman,
I'm going to assume here that you took the vehicle in somewhere and had the full flush done rather than a drain new filter and refill. From what I have heard this is the only way to do it, partial changes with different fluids isn't going to work, or at least I don't believe it will.
Because I'm not doing the full flush I'm going with a couple of partials, I have some LG 6 left over from a previous D3 and I bought some more LG 6 this morning, getting delivered by Securicor tomorrow.

Much as I would like to try a different fluid I don't have the cash spare at the moment to deal with terminal gearbox problems. It will be interesting to see how you go when you tackle the Flinders.

I'm going to do a video of changing a plastic to a steel pan on Friday and then post on YouTube for the world to see. Should be interesting...................:)

An add on point, when I replaced the tranny module on my D3 a few years ago I had to "reset" the gearbox using my Faultmate MSV 2 to get everything talking to everything again, if I change the oil and do the gearbox reset does this reset everything in the gearbox, possibly something that is causing the slight issue I have in the first place.............anyone know?

[winaje]

An add on point, when I replaced the tranny module on my D3 a few years ago I had to "reset" the gearbox using my Faultmate MSV 2 to get everything talking to everything again, if I change the oil and do the gearbox reset does this reset everything in the gearbox, possibly something that is causing the slight issue I have in the first place.............anyone know?
The box automatically adapts to the new oil, takes a couple of hundred kms though. Can't hurt to do the reset.

[Nomad9]

Hi There,
So the steel pan conversion kit arrived, Securicor delivered the transmission oil and I found a couple of hours to spare.

Bit trickier to do than the TDV6 the exhaust goes under the gearbox on the petrol engine model. No option other than to remove the cross member to get the pan out.

Two of the four bolts holding the heat shield frame in place were a PITA to get out, cut a couple of threads off the bolts made things a lot easier getting things back together, just that fraction to long, one between the prop shaft and the other between the gearbox linkage.

Took it out for a test drive and been driving around all afternoon, perfect, everything is back to normal, sweet as.

If the markings inside the old plastic filter are anything to go by I would say that this was the original filter assembly..............190k I reckon it was just about due for a change.

Just a bit of a close out to let people who participated in this thread to let you know alls well that ends well.