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Old 08-10-2012, 12:36 AM   #1
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Location: Ridgeland, MS
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..::|TrippinBimmer & GM 5L40-E: Transmission Mods|::..

I have been getting tons of PM's about what are my plans for my Transmission. I have been very low key about this until now. This will benefit only a few people who would like to take the Automatic Transmission to the Max.

First, here is some History on this Transmission:
The 5L40-E was designated in either "M82" (rear-wheel drive) or "MX5" (all-wheel drive) versions for service in BMW vehicles from 2000 model year until the design was superseded by (for BMW) the 6l45e and (for all others) the 6l50e series electronic automatic transmissions in 2007 . It is designed for service in vehicles up to 4000 lb (1814 kg) GVWR and in service was mated to a selection of final drive ratios 3.42:1, 3.73:1, or 3.91:1 depending on the carline. The 5L40-E had been designed for 1.8-3.6 L engines with a maximum of 250 ftlbf (340 Nm) of torque. A notable failure mode of the assembly is lifetime overtorque in the heaviest carlines wherein the unit is matched with a significantly higher torque-rated powerplant; the transmission is well known for failing between 150,000 km and 200,000 km in the 5 series E39 and X5 BMW'S equipped with their inline 6-cylinder and V-8 powerplants, due to insufficient or contaminated lubrication during operation in cruise overdrive range, and service loads beyond the engineered maximum rating of the unit. Despite this apparent mismatch, and since carmaker BMW does not manufacture the extremely sophisticated 5l40e, BMW customers have reported that Authorized BMW Service will not repair this type of transmission, instead offering to install fully assembled units as replacement (a common practice which entails significant cost to the consumer.) An aftermarket preventive package exists to curtail early failures but is designed to alleviate very specific symptoms and generally is not a prescribed remedy for a manufacturer mismatch.
Gear ratios:

  • 3.42
  • 2.21
  • 1.60
  • 1.00
  • 0.75
  • 3.02

I will be doing this in 5 stages.

1. Dinan GM Transmission Tune (Moderate Priority)
Sporty acceleration is no longer the sole domain of those who like to shift gears; Dinan Automatic Transmission Software welcomes you to the performance zone. In order to take full advantage of the higher rev-limit provided by Dinan Engine Software the transmission software raises the shift points to a higher rpm, allowing you to carry more road speed in each gear. In addition, vehicles equipped with shorter final drive gearing are then able to achieve at least 60 mph in second gear with the higher shift points for optimum 0-60 performance.

Dinan Transmission Software may only be installed in conjunction with the matching Performance Engine Software as there is no benefit without the higher rev-limit.
2. Eco-Tuning Mod (Arrived )
An early converter lockup:
No converter slip, not a rubber band effect.
Reduced fuel consumption.
Lower oil temperature.
Better lubrication.
Better heat dissipation due to lower oil temperature.
Slower aging oil.
Reduced wear on the gearbox.
Reduced wear on the lock-up clutch.
As fewer repairs.
More driving fun through the direct transmission of power.
3. IPT 5L40-E Modified Valve Body (High Priority)
Reduce or Eliminate the Shift Overlap
Reduce Wear
Crisp Shifts
4. IPT Custom TQ Converter (Low Priority)
Increase performance and reduce ET by .5 to 1 full second over a stock converter.I PT is able to custom modify your converter to suit the characteristics of your vehicle. Improved bearings, lock up clutch material and furnace braised fins yield a tremendous increase in strength and durability.
5. 5L40E Performance Transmission Rebuild Kit (Very Low Priority/Undecided)
IPT now offers High Performance Master Rebuild Kits for BMW transmissions. These kits include all necessary seals, gaskets, filters, shifting bands, friction clutches, pistons, and reaction plates that are required when rebuilding transmissions. This is the same kit use in our Built Transmission.
These are my plans and will be done slowly. I might not even get to number 5 on my list. I will keep this thread posted and how it goes.

2005 AW/IR M3
MaximumPSI Stage4
993whp/651wtq SAE Corrected

2005 JB/BLK 330i ZHP
NAwhp/NAwtq SAE Corrected

1996 BLU/BLK M3
NAwhp/NAwtq SAE Corrected

1988 SETA 325I
NAwhp/NAwtq SAE Corrected

Last edited by TrippinBimmer; 09-20-2012 at 01:08 PM.
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