Td6 5L40E Options

Rhys with your knowledge of these boxes, what do think is the maximum safe engine output for these autos. Given that the standard L332 Td6 is rated at 174 bhp and 288 lb.ft; most re-maps give 212bhp and 350 ft.lb and the Jeremy Fern Intercooler kit and re-map give 250 hp and 420 lb.ft
I would love the extra power, but don't want to over-stress the box; I would use the H/D output shaft though.

Laurie

Hi Laurie

Sorry to disappoint you but you cant get the super duper Jeremy Fern intercooler/remap any more . He took it of the market as the gearbox couldn't handle the power. Had a few emails from him on this subject

Gary

Thanks Gary, it would have been my preferred option down the track if the box could safely handle it.
Laurie

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Originally Posted by Laurie

Rhys with your knowledge of these boxes, what do think is the maximum safe engine output for these autos. Given that the standard L332 Td6 is rated at 174 bhp and 288 lb.ft; most re-maps give 212bhp and 350 ft.lb and the Jeremy Fern Intercooler kit and re-map give 250 hp and 420 lb.ft
I would love the extra power, but don't want to over-stress the box; I would use the H/D output shaft though.

Laurie

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There are a few design issues which make these weak in terms in hard part damage.

1st. Is the "DIRECT CLUTCH HUB AND SHAFT ASSEMBLY"
https://www.aulro.com/afvb/images/im...12/07/1318.jpg

The Shaft section cracks like a spring coil and expands under load grabbing the Overdrive shaft and locking it up causing the car to completely lock up when 5th gears is trying to engage. (This is a problem with the upgraded power)

2nd. The Transfer puts power to the front wheels (NV125? i think) The spline on the front shaft and the spline on the transfer both strip out. This loses drive and reverse but also has a very bad noise as the splines just chatter over each other.

3rd. Pressure drop & heat can lead to the forward clutch to fail either loss of pressure due to filter blockage or pressure leakage through leaky valves. Over heating of the oil can send the clutch pistons hard and then cause leakage and slippage.

The Output shaft issue i have never come across in a 5L40E but the BMW X5 seem to blow the transfer spline on the Front shaft.

The strange thing is if you line a ZF4HP24 and a 5L40E up next to each other the 5L40E has heaps more internal strength when you look as each gear next to each other but the 4HP22 & 2HP24 only ever seem to have hard seals due to the age of the transmission compared to the many issues the GM box has.

As i said in my first post if you can cover all bases it should work a treat but to what lengths do you go to do that.

Cheers
Rhys

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Originally Posted by bacicat2000

Hi Rhys, great to have you on the forum and for you to share your knowledge on these boxes.

Despite the issues I had originally, I really appreciated your commitment to getting me back on the road again - it has been going like a dream since.

Cheers - Gav

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Good to hear Gav.