Citrojim's Pixo, Saxo and Cycling Tales

DickieG · Post by **DickieG** » 18 Dec 2009, 23:22

CitroJim wrote:I'm a massive HHGTTG fan as well....

Eh? Have you been on the sauce?

XantiaMan · Post by **XantiaMan** » 18 Dec 2009, 23:26

I'm a fan of ROTFLMFAO.

CitroJim · Post by **CitroJim** » 18 Dec 2009, 23:29

DickieG wrote:
CitroJim wrote:I'm a massive HHGTTG fan as well....
Eh? Have you been on the sauce?

No, Dexron

HitchHikers Guide to the Galaxy Richard!!!

Indeed Gareth, a lot of the HHGTTG stuff does have me ROTFLMFAO quite frequently 8)

Sl4yer · Post by **Sl4yer** » 19 Dec 2009, 00:02

There's definitely an alternative career in autobox repair for you Jim. Shame they're not designed to make a fluid and filter change simple, although that's probably not by accident.

Computer systems at my employer seem to work on a SISO basis, IYKWIM!

James

Post by **xantia_v6** » 19 Dec 2009, 09:56

CitroJim wrote: The failure was caused by lubrication failure resulting from a clogged oil filter. The filter is so clogged, oil will barely run through it.

Good work Jim.

Those bearings need oil pressure to operate, so maybe the filter got to the satate where there was 0 pressure at idle, and that killed the bearing?

That could be almost independent of the original symptom (lack of forward drive) caused by lack of pressure at higher revs?

BTW, what is the filter clogged with, and where did it come from?

lexi · Post by **lexi** » 19 Dec 2009, 14:58

Excellent stuff Jim. Apart from whipping out box it must still do some good to change out oil anyway?. That oil is usually carring fine particles around.

Those HP422 AND HP424 Boxes in Landrover can be sump pan dropped and filter changed. They also run on Dexron. Tell me this? Is it possible that ZF merely changed the lube spec on 20 box to the Esso semi synth because they knew it would be in for life?
Or would that box have run with Dexron from the factory at new? Obviously you cannot use Dexron but would that be more to do with the mixing issue? I am just curious as to the difference between these similar high tech ZF boxes which take Dexron and our 4HP20 that don't.

Post by **xantia_v6** » 19 Dec 2009, 16:48

The problem with changing the fluid (as a preventative) is that the filter is very efficient, so the debris is largely already gone from the fluid you drain.

It might be useful if there was some way of attaching a pressure guage, as that should give an early indication that the pump is struggling to pull fluid through the filter.

lexi wrote:Tell me this? Is it possible that ZF merely changed the lube spec on 20 box to the Esso semi synth because they knew it would be in for life?

When designing an automatic transmission, you start with the fluid spec, and design the transmission around it.

The 4HP20 fluid is nothing like dextron in viscosity, feel, or smell (you can try the taste test

).

lexi · Post by **lexi** » 19 Dec 2009, 20:44

so the debris is largely already gone from the fluid you drain.

How do you know that if you haven`t had the oil professionally tested for particle and other contaminents?

I have had this done on other autos with filters and they have always reported metal and other things in fluid. Admittedly some were band type boxes which wear and shed metal. Millers normally advise if they think it to be a problem. All have had similar metal filters to 4HP20. Maybe this box don`t have fine metal? When I drop sump contents I may give them that to check as it could be useful for forum data. Jim could end up getting a Phd out this

Semi and fully synthetic auto fliuids that take the place of and are used in Dexron boxes also have a different feel and smell to the original fliud.

I think for a long time there only were about 3 basic fluids used. Ford and GM (Dexron) being the more popular.

When designing an automatic transmission, you start with the fluid spec, and design the transmission around it.

Wel I don`t doubt that V6

You can only design around what`s available. at the time. Granted the spec can and will be exceeded and can sometimes but not always be used . That may however make the case that an oil can be used that the box was not built around at the time as long as it has the same properties that the design requires.....I take it this is what you mean?

My queries were leaning toward what was different with the 22 and 24 boxes in the workings that made it use Dexron rather than the Esso. Also the fact that very very few other boxes use that fluid so what is Esso specific in relation to the 4HP20 box in that matter?.

Just Musing

Deanxm · Post by **Deanxm** » 19 Dec 2009, 21:59

xantia_v6 wrote:
CitroJim wrote: The failure was caused by lubrication failure resulting from a clogged oil filter. The filter is so clogged, oil will barely run through it.
Good work Jim.
Those bearings need oil pressure to operate, so maybe the filter got to the satate where there was 0 pressure at idle, and that killed the bearing?

That could be almost independent of the original symptom (lack of forward drive) caused by lack of pressure at higher revs?

BTW, what is the filter clogged with, and where did it come from?

On the Box im working on there are test ports on the outside of the casing to test delivery pressure direct from the pump and line pressure from the centrifugal shift regulator, now i would have thought although mine is not a HP20 (its a hydro mechanical HP 18 ) that its sister box would have the same ports for pre removal diagnostics, they are well hidden on the box but you can get at them without too much hassle and it could be a simple test to carry out at idle come service time which may help spot any upcoming problems, i may fit a perminant pressure guage to my box when i do the engine conversion as like an engine oil pressure guage it could just save you from disaster.
So the question is did you see any small diameter drain off style plugs in weird places when you stripped these boxes Jim?

D

CitroJim · Post by **CitroJim** » 19 Dec 2009, 22:10

Deanxm wrote: So the question is did you see any small diameter drain off style plugs in weird places when you stripped these boxes Jim?

Yes, and quite accessible too, on the front of the 'box there is one such Dean.

I'll investigate further. I'm sure the manual tells the pressures.

Deanxm · Post by **Deanxm** » 19 Dec 2009, 22:21

mine are on the front of the box too but under the battery tray/lhm res so you would need bendy arms to get to them without moving anything

I keep meaning to check mine but i dont have a fault yet, im not keeping the box and it is well down the list of things to do.
Would be intersting to compare a couple of boxes pressure though, especialy one with a whine...............

D

CitroJim · Post by **CitroJim** » 21 Dec 2009, 21:01

It's something to look into when the weather gets a tad better. The 4HP20 can run up to about 18 bars so a 20 bar gauge will be needed I reckon.

Mike, I cannot tell what the filter was clogged with but in common with every other 4HP20 I've stripped I found every surface coated in a fine grey deposit. I suspect general wear and tear from the clutches and brakes.

The magnets in the 'box looked like they were disguised as startled hedgehogs but then that's pretty normal and as this one had magnets on the filter (yours didn't but it has now!) so it was not swarf. No appreciable debris in the 'box itself so I can only conclude the filter just plugs over time with the aforesaid grey stuff.

I shall dissect the filter at some point and see if it gives up any further clues.

Saturday saw Richard and I do a bit more breaking of the V6 in what seemed like sub-zero temperatures. At least the sun was out

but by golly, it was perishing. I kept loosing the feeling in my fingers

Richard seemed warm enough and at the end he revealed his secret: Quilted overalls

I want some!

Richard, thanks a million

Every bit stripped is one bit closer to the shell being disposed of!

May I point out that there is still some useful stuff on this V6 like very straight wings, bonnet, doors, tailgate and interior bits. Please, if there is anything at all you would like before the remains goes to the great car park in the sky, get in touch with xantia_v6 soonest.

I'm shocked to the corre that we have not been crushed in the stampede for the lovely leather interior

Further breaking is now at a halt for a while. It's snowing hard here at the moment. I needed to go out in it and I was impressed at how the V6 performs in snow mode. No traction issues at all, just an issue with stopping as the ABS is very keen to effectively prevent any braking on ice at all. I'm just glad I was the only one coming up to a traffic light on red in the middle of a patch of pure ice

Time now to do some work indoors. I shall be thinking of properly writing up my 4HP20 ovehaul guide and publishing it on my other website www.xantiav6.co.uk I plan it to be a collection of useful V6 stuff but one thing there will not be is a forum. We already have a perfectly good one here in the FCF and readers of xantiav6.co.uk will be directed here for forum access.

lexi · Post by **lexi** » 21 Dec 2009, 21:04

Sometimes but not always I get a 2 second whine when going from park into reverse from cold........ideas?

DickieG · Post by **DickieG** » 21 Dec 2009, 21:45

CitroJim wrote:Saturday saw Richard and I do a bit more breaking of the V6 in what seemed like sub-zero temperatures. At least the sun was out but by golly, it was perishing. I kept loosing the feeling in my fingers

Richard seemed warm enough and at the end he revealed his secret: Quilted overalls

Those overalls are brilliant in this freezing weather, in fact they are so warm that the next morning @ 8am I was under a Xantia changing sphere's whilst lying on sheet ice and started to get a bit sweaty! Get yourself a pair of "Dickies" quilted winter overall's.

As Jim states the bodywork and leather interior of this V6 is very good indeed so it will be a shame to see the bodywork parts get thrown away due to the lack of available storage space, I can see that the forum needs to start up a parts warehouse storage fund/facility

CitroJim · Post by **CitroJim** » 21 Dec 2009, 21:49

Lexi, I know this is difficult but can you describe the whine? Is it a harsh sound, a gentle sound, loud, quiet? Like a diff sound or like metal on metal? Or is it a "whirr" sort of a whine?

Dies it "snatch" a bit if you go between R and D and back again?

Question 1 has to be this. When did you last change the gearbox oil?

My suspicion is that it's taking a while to get oil pressure right up and there is not quite enough pressure to fully engage the big reverse Brake D on the gearset and it's slipping a bit.

This brake has a huge piston, is "hungry" for fluid and has to brake a rapidly spinning epicyclic annulus to a dead stop. The gearset is a weighty lump and has some considerable inertia. It is only when going into reverse that the whole gearset is brought to an abrupt halt. Any pressure deficiency will surely show there. The B Clutch that transmits power to the gearset is already engaged at this point in readiness so the D Brake is the only element that actively operates going into reverse. Also, it is only in reverse and first that the pump is called upon to deliver the maximum (16 bars or so) of pressure to engage clutches. In all other gears about half this pressure is required and used for gear selection.
In first the F brake is engaged and this is a tiny squirt of a brake compared with the D brake.

If it only happens once when cold, then no worries (too much) but I'd be changing the oil sooner rather than later and be keeping my ear open for the whine getting louder or being present for a longer period. I'd be worrying too if it appeared when going backwards under power.