I am running out of options and running on limited knowledge, even though most of us row our own gears but sometimes manual transmission isn't in the cards so I figure I would still ask. Anyone have any recommendations for something like this?
I am trying to put a GM 6L80/90 transmission behind a big block - which was never offered from GM on top of this. I've found out nobody has done this before. Horray me...
PTC, BTE, Circle D to name a few to check....
Doing some google-fu at work led me to this, Florida Torque Converter
FTC Part #:
Price:Call
Application:
Make/Model:2009 - 2010 CHEVROLET SILVERADO 4500 6.6L HD DIESEL
Transmission:6L90
Diameter:12.5"
Spline:36 SPLINE STATOR
Pilot:1.703"
Hub:1.834" FLAGED & SLOTTED
Mounting:6 SLIGHTLY EXTENDED MOUNTING PADS
11.5" BOLT CIRCLE
1.080" PAD HEIGHT
10 x 1.50 THREADS
Clutch:YES WOVEN
ID Code:JMDZ
Notes:IF 3 PAD USE 77-JMDZ
CAPTIVE CLUTCH RIVETS ARE VISIBLE ON COVER
The 8.1 flexplate is unique, but this may work..
06HHR said:Doing some google-fu at work led me to this, Florida Torque Converter
FTC Part #:
Price:Call
Application:
Make/Model:2009 - 2010 CHEVROLET SILVERADO 4500 6.6L HD DIESEL
Transmission:6L90
Diameter:12.5"
Spline:36 SPLINE STATOR
Pilot:1.703"
Hub:1.834" FLAGED & SLOTTED
Mounting:6 SLIGHTLY EXTENDED MOUNTING PADS
11.5" BOLT CIRCLE
1.080" PAD HEIGHT
10 x 1.50 THREADSClutch:YES WOVEN
ID Code:JMDZ
Notes:IF 3 PAD USE 77-JMDZ
CAPTIVE CLUTCH RIVETS ARE VISIBLE ON COVERThe 8.1 flexplate is unique, but this may work..
I found that as well and that is the pattern for the flexplate I have on the big block, I've never seen a 6l90 behind a duramax (they all got allisons, and the BB kodiaks never got 6l90's just allisons) which makes me think this is a typo. Plus the image shows that goofy raised hump on the tq converter housing that will interfere with the flexplate (which is one of the issues I am having now)
also the hurricane didn't fare too well with them, they said they would be up and running in about a week.
Ranger50 said:PTC, BTE, Circle D to name a few to check....
Circle D seemed to be the most knowledgeable on the trans itself, I'll have to call up PTC and BTE.
I'm not sure about things like TC hub diameter and shaft depth (i.e. if the TC is deeper or shallower in the bellhousing compared to, say, a 4L85E, but can't you just do what I often do... re-drill the flexplate for the right pattern? Spacing it a possibility if the TC is too far away. Not much you can do if its too close.
I've done that before many times. I put an HD TH400 TC behind a Caddy 500, so I just drilled the flexplate for the extra three holes to make 6. Also turned a large-pattern GM flexplate into a small pattern the same way.
curtis73 said:I'm not sure about things like TC hub diameter and shaft depth (i.e. if the TC is deeper or shallower in the bellhousing compared to, say, a 4L85E, but can't you just do what I often do... re-drill the flexplate for the right pattern? Spacing it a possibility if the TC is too far away. Not much you can do if its too close.
I've done that before many times. I put an HD TH400 TC behind a Caddy 500, so I just drilled the flexplate for the extra three holes to make 6. Also turned a large-pattern GM flexplate into a small pattern the same way.
That would work except the torque converter housing has a buldgy outer surface that does not accommodate (interferes) with the big block flexplate. The LS flexplate is sunken in on this area so there is no crash condition.
Also I called up BTE - they don't mess with the 6 speeds, so I called PTC and they referred me to TCI who I am waiting a call back from for a possible solution.
How much interference are we talking? What about an aluminum or steel spacer between the bellhousing and mounting surface, and corresponding taller mounting pads between the torque converter and flexplate?
93gsxturbo said:How much interference are we talking? What about an aluminum or steel spacer between the bellhousing and mounting surface, and corresponding taller mounting pads between the torque converter and flexplate?
I need 1/8" thickness increase on the mounting pads of the tq converter to allow the flexplate to clear. I would need to hog out the holes slightly for it to bolt up still.
You are suggesting I make a bellhousing spacer the same thickness? Then everything should fit as intended?
In that Photo the T Q on the left has the tranny side up and the Flexplate side Down .
the tq on the right has the flexplate side up. it appears to have A cover over the input shaft opening.
Reply to Fidelty 101 and Curtis 73: I checked TCI's website before I left work, they have a few flexplate options in the 168 tooth size that appear to allow for drilling extra holes for different patterns. Some are already drilled for two patterns. How's it feel to be a trailblazer?
fidelity101 said:I am trying to put a GM 6L80/90 transmission behind a big block - which was never offered from GM on top of this. I've found out nobody has done this before. Horray me...
That's BS. Plenty of people have put 6l80s behind big-blocks. Hell, I was almost one of them until the vehicle owner decided that he'd rather have a T56 for some damned reason. (604 cubic inches in a 3400 pound car does not make for a happy manual trans experience, in my experience, but what the hell it's not my money)
fidelity101 said:You are suggesting I make a bellhousing spacer the same thickness? Then everything should fit as intended?
If you genuinely need to make a spacer, and it's not a case of the torque converter not being fully seated, and it only needs to be an 1/8" or so, I'd just get a BOP to Chevy adaptor and drill the holes through and use that as a spacer...
that or find a used Mid-Mount Plate to cut to size, If your Fingers fit between the T Q and back of the Case, It's not seated in all the way.
fidelity101 said:93gsxturbo said:How much interference are we talking? What about an aluminum or steel spacer between the bellhousing and mounting surface, and corresponding taller mounting pads between the torque converter and flexplate?
I need 1/8" thickness increase on the mounting pads of the tq converter to allow the flexplate to clear. I would need to hog out the holes slightly for it to bolt up still.
You are suggesting I make a bellhousing spacer the same thickness? Then everything should fit as intended?
Thats exactly what I am suggesting. 1/8" isnt enough that the converter won't be piloted in the crank (you did check to make sure it will still be piloted in the crank, right?) and you can easily get any one of a dozen local shops with either a laser, waterjet, or HD Plasma to whip you out some spacers in .1345 (10 gauge) steel if you have the CAD, or use transfer punches and trace it out/band saw and drill the old school way. One spacer of your bellhousing bolt pattern including the dowel pin holes, and three smaller ones to act as spacers between the torque converter and the flexplate. This will keep the relationship between the converter and the pump the same (no seating issues) and moving the trans back 1/8" is not enough to affect any of the centering features like the bellhousing dowel pins or the pilot in the torque converter/back of crankshaft.
Knurled said:fidelity101 said:I am trying to put a GM 6L80/90 transmission behind a big block - which was never offered from GM on top of this. I've found out nobody has done this before. Horray me...
That's BS. Plenty of people have put 6l80s behind big-blocks. Hell, I was almost one of them until the vehicle owner decided that he'd rather have a T56 for some damned reason. (604 cubic inches in a 3400 pound car does not make for a happy manual trans experience, in my experience, but what the hell it's not my money)
How sure are you? If you know something I don't please tell me :) I'm all ears...
I think a 454 truck flexplate would fit (pattern wise) but not clear the tq conv body since its pretty similar to the 8.1 flexplate.
In reply to 93gsxturbo :
I did check for that and it does fit.
I'd be surprised myself if no one has done it. GM sells everything standalone to actually do it, all someone needs is the $ and the know-how. Or really just the $. Haven't you seen them reality shows on TV? They can do anything in 60 minutes.. Seriously though, they have a standalone TCM for the 4L series of GM transmissions, how different are the 6L series IRL to transmission control:
EDIT: I found this thing Standalone according to the company literature the issue is that the TCM for the 6L series is internal to the valve body and standalone options that worked with the 4L do not work with the 6L. It can be done, just not without $.
You'll need to log in to post.
