Thread: More 5L40E problems

Harlie
If they are doing a full strip; any chance of some photo's ? To my knowledge it would be the first time we could compare the innards with the photo's RRPhil posted of the early 5L40E teardown.

Td6 & Auto - Tech Pictures

Also Don could cast his eyes over the photos and see if they did indeed use parts from the 5L50E version. Which would prove they "did know the box was under rated for this application"
I would be particlarly interested in see the T/C as it was supposedly "improved" and a new part number added.

Laurie

Would be difficult to spot differences!
Main case casting same; just different drillings/drains here and there in same cast-in spigots.
Oil pump same; obviously bell housing different.
Sprags same.
Externals of all clutches same except subtle differences in lengths of hollow shafts/spline lengths.
Clutches in 5L50E-- most have extra disc/plate (that stated extra power handling???)
Planetary- 5L50E has slightly "longer" gears.
That's it!
Well that's it from the XLR Caddy box anyway; I doubt GM would have made other changes between 5L50E's for different cars/makes.
Don

So… I will have my car back on Friday.

Post mortem results: Failed pressure regulator valve.

The valve body pressure test (with new valves) was in the normal range but only just – so valve body wear was not THE issue, however with my “do it all” attitude towards this, it is receiving the full sonnax treatment (sent away). The decision to sleave opposed to fitting a new body was made after an interesting chat with the repairer that has the car. His story is also talked about by a UK repairer in one of the discussions I found. What these guys have found is that the various versions of the 5L40 have minutely different bodies. When fitting exchange units (several years ago now) they found issues with some transmissions when fitted with a rebuilt body that originated from different model. They have not had any problems rebuilding the valve body and fitting it back in the same box – provided it was not completely stuffed, which he admitted they rarely can be. Down side is time.

TC lockup clutch still has a bit of meat but was slipping due to pressure. The initial oil sample was relatively clean but when the pan was removed it had a lot of clutch lining material in the bottom, so the clutch was in the process of shredding itself.

No metal filings found.

Shift clutch packs still in good nick (getting replaced anyway).

The TC specialist is of the opinion that my TC has a significantly thicker clutch plate than the 2002 he did last week. Interesting? Was it the very early ones that were warping?

I will post up some pics on the weekend. With the full list.

Can’t wait to get the old girl back – I asked for a lower stall speed Torque Converter which has arrived - should be nice.

If I had continued to drive it things would have got worse quickly. I suggest that most failures start out like this, the very subtle signs are not noticed, eventually the filter blocks and fluid supply is lost resulting in no gear selection.

I could have got the car back and going with a replacement regulator valve and Torque Converter. But given the risk of these, It is recieving the full monty, the list is long - I'm keeping the car make it last.

Harlie
It was good to see it was the pressure regulator in the first instance. you have caught the low pressure gremlin early. I totally agree with your decision on the rebuild though, not only on future costs basis but most of all peace of mind. I've always disliked the T/C setup in these boxes and it's good to hear the later models LR have attempted to address this shortfall. I will be very interested to see if the T/C lockup points have been reduced, with your new low stall T/C or better could be had by installing the Ecotuning unit also.
I think a heavy duty T/C replacement in the early KLM'S of these boxes is a worthwhile long term investment..

How does your auto rebuilder rate the strength of your box after these mods, would it be ok for a "chipped" Td6 or not ? just looking at it long term for future enhancements.

Laurie

Originally Posted by Laurie

....

How does your auto rebuilder rate the strength of your box after these mods, would it be ok for a "chipped" Td6 or not ? just looking at it long term for future enhancements.

Laurie

I asked him about the retune during the initial diognosis last week - I've been running ~500nm for quite a while. His opinion - not a problem, he has been building versions of the box for blokes with "stupid horse power" - "fix the pressure problems and they are a top box".

After seeing the clutch that came out of my TC, I'm not worried at all (must admit I was last friday). If it wasn't for the pressure valve it would have had a lot of life left after 183k.

Point that was backed up during conversations with a well-regarded trans rebuilder in Sydney on Monday (we all know him). He is so convinced that pressure is the main issue he is recommending the pressure valve be replaced as a scheduled maintenance item – every 3 years. It is right there when the filter is removed & doesn't cost much, swap it over during a fluid change… That conversation was before we knew what went wrong with mine, and it would have saved it - The fluid was clean when I changed it at xmas.

Hi Harlie,

I just had my transmission serviced as I had started to get a bit of a shudder intermittently when under load. They pulled the pan of to inspect and found no sediment but commented that fluid was dirty. Based on what you have said do you reckon it would be worth taking it back and getting them to replace the pressure valve....what's approx cost for the valve?

Steinzy
The Borg-Warner unit is your best option, I don't know what local costs are though ! The link below is to a PDF

https://docs.google.com/viewer?a=v&q...QcDLvo3cC7rw1A

Laurie

Originally Posted by Steinzy

Hi Harlie,

I just had my transmission serviced as I had started to get a bit of a shudder intermittently when under load. They pulled the pan of to inspect and found no sediment but commented that fluid was dirty. Based on what you have said do you reckon it would be worth taking it back and getting them to replace the pressure valve....what's approx cost for the valve?

When was it shuddering? My first symptom was a vibration/harshness - TC was locked, top gear under load, lift off and it smoothed out.

Has the fluid change fixed the symptom? If it has then yes - ask Qs about the AFL valve or the kit which includes the sleeve, and the regulator kit. Clean fluid improves line pressure, but it also allows the valves and pistons to operate at their designed speed and force.

You need someone with the tooling to do the AFL valve sleeve, once things get bad the valve body needs to be machined and sleeved. There is a real chance you could replace the valve and achieve nothing because the valve is not sealing on the body or the pump is buggered, or the regulator is buggered, or the case is worn, or, or, or.

If you have slippage ask Qs NOW - don't drive it.

I had not felt any vibrations or other issues until a couple days ago. Previous fluid changes made no difference to the operation of my trans. If a fluid change improves things the fluid must be horrible.

I don't have the price list yet, but these bits are not that expensive – I just have a long list. He read the list out to me this morning and most of the work is pressure rectification or further prevention. I will post up the parts prices once I get it home. I think the fluid would nearly cost more than the valve.

I think it is interesting to note, the repairer here in BNE and our well known member who rebuilds these boxes in SYD (whom I spoken to at length several times) both said exactly the same thing. Failures are 100% pressure related, you can fit the biggest TC in the world and it will chew out because the pressure will drop. The obvious symptom is the TC clutch (so we all blame the TC), it is usually spread throughout the box when it is opened, but the problem was line pressure, even in the early versions that warped the clutch plate – it didn’t warp until it after it was slipping, which was after the pressure dropped. And we are not talking a small drop either. They both were not that interested in the HD converter from Melbourne – “we can fit that if you want, but it isn’t the issue” – sort out (and maintain) the fundamental design issues that affect pressure and they last. Given this bloke was doing all the warranty work for BMW (still is) in SEQ when the 5l40 was becoming famous and they are all still going strong, I tend to think he may know what’s what.

I’ve lost interest in the talk about torque converters, especially after my conversation with the bloke in Melbourne – his knowledge of 5l40s was nill and his knowledge of TD6 Range Rovers was nill. Apparently the factory TC stalls out at 2500rpm… So none of these cars revved out above 2500 from new.

Anyways my car is on the road now all tested, but can’t get out until tomorrow