Range Rover Vogue 3.0 Td6 54 reg

Bemble said:

I documented the teardown of a faulty TD6 GM 5L40E transmission here :
GM 5L40-E teardown - Xoutpost.com

Unless a re-manufacturer has replaced with new or upgraded the valve blocks with the Sonnax kits, any re-manufactured 5L40-E is still on borrowed time as the root cause of the failures hasn’t been fixed – the torque converter lock-up clutch will inevitably fail again due to low engagement pressures caused by excessive spool leakage and cross-talk, and dump a load of metallic debris into the sump. The only question being when.

The best you can do, therefore, is to get a re-manufactured transmission with as long a warranty as possible and then expect to be replacing it again at some point in the future. The only alternative is to invest in the Sonnax kits or new blocks, and ensure you keep the Texamatic 7045E fluid clean by replacing it every 30,000 miles or so.

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so are you saying the upgraded sonnax kits will resolve the root cause of failure and stop it from happening again ?

I understood the words and I loved the pictures but . . . . . .
I think I'll ask James to do any work I might need, even on my ZF box !!!!

2.0_hippo said:

so are you saying the upgraded sonnax kits will resolve the root cause of failure and stop it from happening again ?

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Where the cause of failure is valve block wear (due to the extra-soft aluminium which GM used for their castings, presumably to speed up machining time & reduce replacement tooling costs) which causes spool valves to leak and therefore lose hydraulic pressure, replacing the torque converter and burnt out clutches and sending the transmission back out again means that it may well last for the length of the warranty period but who knows how long beyond that?

Fitting the Sonnax valves either involves reaming out the worn bore and fitting an oversized spool valve or opening out the bore still further and fitting a liner plus a new spool valve. At worst, this should reset the transmission to ‘new’ condition and theoretically give another 80k-100k miles durability.

I must admit I toyed with the idea of re-manufacturing Range Rover 5L40-Es by uprating them to the later 5L50-E spec. and also fitting a full set of Sonnax valves and sticking on a 5-year warranty. With 50,000 L322 TD6s out there, maybe there’s a market for an uprated transmission?

Bemble said:

I must admit I toyed with the idea of re-manufacturing Range Rover 5L40-Es by uprating them to the later 5L50-E spec. and also fitting a full set of Sonnax valves and sticking on a 5-year warranty. With 50,000 L322 TD6s out there, maybe there’s a market for an uprated transmission?

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Sounds like a good plan to me!

StuckAgainSteve said:

Sounds like a good plan to me!

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Well no one else has done it yet

And I will have one when / if my box gives up any time soon

StuckAgainSteve said:

PS Where are you located? Get the car transported to an autobox specialist such as Stephens engineering unless you want it "fixed" by a bunch of clueless spanner monkeys which will end up costing you more than if people who actually understand automatic transmissions work on it - if you're lucky it might only need a clutch pack.

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hi where abouts is this place we are in surrey thanks for your help the independent report says that the torque converter is shredded (drop end clutch the sump and oilfilter are filled with metal fragments

hi i have a 2004 td6 range rover failsafe warning comes on ten seconds only every journey, think the problem is with potentionmeter as bemble said have had it on a code reader code 30 mechanical torque converter,monitor fault and code 85, can bus transfer box time out.i am hoping bemble may pick up this post thank you paulpig 321