I've been getting quite a few of the same questions regarding the conversion of a 6L80/90E transmission into a Trailblazer SS, so I figured I'd post it here. With enough interest, maybe it can become a sticky. I will update as more questions are asked.
What is the speed/power limitations of the 6L80/90?
The 6L80/90 has a maximum RPM limit of 6500 RPM.
Not all 6L80/90's are the same. GM states, "There is also a 6L90 "Lite" version without the additional clutch plate to more closely match application requirement where appropriate."
Maximum engine power: "452 bhp ( 337 kW ), Diesel: 300bhp ( 223kW ) - Truck, 555 bhp ( 414 kW ) - Passenger car"
Maximum engine torque: "531 lb-ft ( 720 Nm ), Diesel: 520 lb-ft ( 705 Nm ) - Truck, 550 lb-ft ( 746 Nm ) - Passenger car"
Speaking with Circle-D technicians (the leading 6L80/90E transmission performance builder), the 6L80/90's have seen failure around 500 WHP behind customer's forced induction cars and trucks. The 6L90 is a wiser starting point choice given it's slightly stronger internal components. Their build up service, featuring their line of custom billet parts and additional clutches are rated to hold up to 800 WHP for $3500+ transmission.
Is the 6L80/90 transmission conversion right for me?
Click here>>>>TBMSport 6L80/90 Performance Evaluation<<<<
Click here>>>>LS1Tech.com Drag Racing Transmission Options Discussion<<<<
What is the difference between the 6L80E and 6L90E?
(4WD left to right:4L70, 6L80, 6L90)
(4WD left to right:700R4, 6L80)
(4WD bottom to top:700R4, 6L80)
The 6L90 transmission is slightly longer and taller than a comparable configuration 6L80 due to it's beefier internals. GM states, ". It is a heavy-duty version of the 6L80 six-speed automatic, with a strengthened input gearset which has two additional pinion gears for six total, and a strengthened output gearset, that uses wider gears than the 6L80. The 6L90 flexibilty extends to the clutches where the 6L90 has one more clutch plate than the 6L80 in each clutch for heavy duty applications. "
The 6L90 case is about 1.4" (35mm) longer than the 6L80 case.
AWD/4WD Transmission-bellhousing to end of output shaft (bellhousing to end of case)
4L70: 26.875" (22.25")
6L80: 27.125" [+.250"] (23.3")
6L90: 28.625" [+1.750"] (24.7")
4L80: 29" [2.125"] (26")
According to GRRRR8.net:
"The body of the case is slightly taller by maybe a 1/8" (and a slightly different slope) and the length is longer on 6L90.... everything else is same..... Torque converter housing is identical! Mounting is identical in front, Manual shaft is in exactly same positon and location, connections same location (easy fit)...
I dont have my cheat sheet with me now but the 6L90 has more clutch plates then the 6L80 and the opportunity for a much better clutch plate setup.... the 6L80 clutches surface area increased something like 50-75% with the upgrade, but the 6L90, already has significantly more and then more on top of that can be added.... also, the Output carrier is significantly larger with much larger pinions and sun gears, etc.., input carrier has 6 pinions vs 4(i upgraded this in my 6L80 already..) some of shafts are significantly larger..., case has more supports and ribbing for rigidity.... and there are things that not many people or "publications" see that make it a much stronger unit than the 6L80.... I will have to get a good list soon..... I seen some before but none of them include all the little things different....
Didnt get a chance to try the 6L90 in yet- should be tomorrow. But I did get a chance to do a quick measurement on the tw case Over-all-heights...I started from the case edge (where the case mates to the bell housing) and moved towards the tail.... see data below:
measurements are in mm and the "x" dim is referenced from case edge at Bell housing-to-case mating point moving toward output shaft end of trans.. The corresponding measurement is the "uppermost" point of the case relative to the Pan mounting surface...
"x" position 6L80 case-----------------------6L90 Case
at bell housing 297.1------------------------297.9
418mm (for 6L80) 257.1 @end
453mm (for 6L90) -----------------------------256.53@end
I hope this makes sense but it shows the relative height of the case--- they are very close and I would think there is 7mm of clearance to the tunnel.....???...... I would hope... but a small hammer would fix"[/I]
What model year and drivetrain configuration Trailblazer SS can the conversion be done with?
Currently, we have only developed a system for only the 2007-09 Trailblazers in both RWD and AWD configuration. We are actively working to address the 2006 and older Trailblazers.
Why can't my pre-2007 Trailblazer SS be converted?
The Engine Control Modules (ECM) that communicates with the 6L80/90 Transmission Control Module (TCM) is programmed to only recognize Gen IV LSx engines. Specifically the 58X crankshaft reluctor ring, the 4x cam shaft sprocket, and relocated externally mounted knock sensors. The pre-2007 model year Gen III and Gen IV motors (LS2 Corvette notwithstanding) operate with a 24x crankshaft reluctor ring, a 1x camshaft sprocket, and knock sensors located internal to the engine.
A mechanical solution has already been designed, however, as it requires an additional harness and partial engine disassembly. This pre-'07 kit would include an one off E40-E67 ECM interface module, E67 ECM, new harness extensions, custom (possible underdrive) harmonic balancer, custom 2 piece timing cover chain, and modified (or new) balanced driveshaft...in addition to 6L90, related components, and T42 Interface Module and dyno tune. It will require that the front cam sprocket be changed (a plus if you're doing a cam/e-fan mod).
This is why the pre-'07 guys are on the back burner and why I prefer a simpler electronic programming solution. If, however, someone local is willing to be the first '06 TBSS, contact me in PM for super discount pricing.
Do these transmissions have rev match on downshifts? Does Tap Up Tap Down feature work?
Rev matching capability is part of the TUTD. It's fully an electronic function, so simply moving the shifter down a gear will activate the TUTD mode, but not the actual action.
Unfortunately, R&D has not gotten far enough to get the TUTD accomplished for the TBSS. Each vehicle and program has different resistor values that have not been explored yet.
What happens to the cluster indicator?
Cluster works just like factory. One interesting feature is when you drop the gear selector below the D the transmission will hold that gear and indicate which gear it is in through the PRND321 display...obviously up to 3rd gear.
What components are included in the conversion system?
All Trailblazer SS's will require, at a minimum, the TCM Interface Module, harness and custom programmed ECM. Yes the ECM can be programmed as any other ECM by your favorite tuner for your specific vehicles other modifications.
AWD TBSS's will additionally require the TBMSport Transfer Case Adapter & Input Shaft Combo kit.
Can you source a transmission for me?
We can source a transmission for your application. Your choice will be salvage recycling, new or custom built. All transmissions will come with a warranty from the transmission source or builder for at least 90 days, unlimited miles.
All TBMSport sourced 6L80/90 transmissions will include torque converter, pan, bellhousing, cooling lines and gaskets. If the transmission is new, then all parts will be new. If the transmission is recycled these included parts may be new, used, or a combination. Quoted pricing will be based on availability and shipping costs.
What additional modifications and parts will be necessary for installation?
The 6L80/90 transmission will require its cooler lines to be cuts and connected to your original factory cooler lines via an included connector kit.
NOTE: BOTH the RWD/AWD 6L80/90 transmissions' case and overall AWD length (bellhousing to tailshaft) are LONGER than a comparable configuration 4L70. However the mere .250" additional length of the 6L80 makes it a direct bolt in swap that does not require that the AWD driveshafts be changed. On the other hand, the 6L90
transmission swaps (due to the transmission's nearly 2" longer length will require the front driveshaft to be lengthened and the rear driveshaft to be shortened. However, the OEM crossmember and transmission mount can be used due to the TBMSport transmission-to-transfer case adapter.
Several different output shaft sizes and configurations exist among the 6L80/90 transmissions based upon what vehicle they came from (CTS-V, Camaro, GMT900, etc). Therefore a custom (usually longer) driveshaft and new yoke specific to the transmission will be necessary.
AWD systems require the installation of our custom adapter, to mate the transfer case to the transmission. The transmission to transfer case adapter fits on the OEM transmission mount using the OEM crossmember and location. The shift linkage cable connects with NO modifications necessary.
Due to the fact that the 6L80/90 use a larger diameter spline output shaft (vs. the 4L70 smaller diameter 27 spline), the transfer case must have its input shaft replaced with the system's included new input shaft. It takes about an hour. That's it.
The OEM propeller shaft parts and locations are not altered for 6L80 transmissions in AWD applications, but the 6L90 transmissions will require driveshaft mods. The module harness is plug and play.
How much do the transmissions weigh?
Transmission weight:258mm converter: Wet: 94-96kg ( 207-211lb )
Transmission weight:300mm converter: Wet: 102-104kg ( 225-229lb )
Transmission weight: w/ 300mm converter
Wet: 109kg ( 240lb ) estimated
Wet: 74 - 88.5 kg (163.2 - 195.0 lb)
Wet: 115 kg (254 lb)
How much does the system cost?
Current TBMSport's conversion system components pricing can be found here:Click Here>>>>TBMSport.com 6L80/90 Pricing Information<<<<
$1025 for the interface module
$2300 (approx list price) for new/low mileage salvage AWD 6L90
$400 (approx) for misc gaskets, oil tube/dipstick, cooler lines, fluids, etc
$1325 for Transmission to Transfer Case Adapter & 32 spline Input Shaft
$1025 ECM/TCM Interface and Harness
$500 Driveshaft/Propshaft Adjustment (may offer new balanced prop shaft as part of kit)
$1200 (R&R labor w/12hr @ $100/hr)
+New Tune (to optimize performance)
$6,750 (approx) + tax and shipping
$1025 for the interface module
$2200 (approx list price) for new RWD 6L90 (or less for salvage unit)
$1025 ECM/TCM Interface and wiring harness
$800 (approx) for misc gaskets, oil tube/dipstick, cooler lines, yoke, fluids, etc
$500 for driveshaft work
$1000 (R&R labor w/10hr @ $100/hr)
+New Tune (to optimize performance)
$5,525 (approx) + tax and shipping
...add $3500 for 800 WHP build!
If I can get 10 people to do it, the AWD adapter kit drops $200 and the ECM/TCM Interface drops $200.