Tahoe 6-Speed T56 Conversion

[livingez_123]

Good job!
When I was working my Dodges, the only trans I would have was Manual. When I moved up to my Volvo, I went with a 10spd over the auto shift.
Now, I prefer my Denali with the auto just because I want to sit back and drive.
My track car, is a manual of coarse.
If I ever get back into a newer Volvo, I will go with an auto shift, just because I'm getting older and don't want to bother with a clutch and shifting. BTW, an auto shift is still a manual trans with ECM controlled clutch and shifting, and you can over ride it at any time with a push of a button.

 

[digitalfiend]

Awesome job man!! Funny I found ya on PT today in searching for parts for my own T56 swap lol.... I was going to mention, depending on your tire height you could definitely go with a deeper rear gear than a 4.10. I ran 4.10 gears in my camaro as a daily driver and also freeway commuting 120 miles a day without a problem and that was with a short 26.5" tall tire. I'd go with a 4.88 at least if your tire is around 30".

Play around with this calculator and you'll see what I mean. You will thank me later.
http://www.ringpinion.com/Calculators/Calc_RPM.aspx

Mike

Thanks for the link to the calculator. A couple years ago I wrote a piece of software that I can plug in different values for tire size, transmission gear ratios, and rear end gear. It lets me see the tire speed, MPH, and engine RPM at any given RPM for all forward and reverse gears that the transmission has. I've now done auto-to-manual+tire-size swaps on my last two vehicles...I also swapped the rear end gear for my last truck too and the software is dead-on accurate. I only want to make a subtle change by going to a 4.10. If gas wasn't so expensive I'd be going to a 4.88 or 5. gear in the rear.

I love to see these conversions! I despise my auto too and hope to do this swap soon. I read that thread over on Performance Trucks a little while back and its great for a 2wd but I'm 4wd so that complicates it a bit for me. I want to run a NV4500 and ditch my autotrac tcase for maybe a 241 or similar.

How's the shifter placement? Is it awkward with the armrest down or is it more comfortable?

...

Depending upon how much time and money you want to invest, you've actually got a couple options. You could do the swap to a 4WD NV4500 like you're thinking, or you could convert to 2WD and swap to a T56 - I know of someone on this forum who's doing this option. If you really want to commit to going way overboard then your third option is to convert to a 4WD bulletproof ZF S6 tranny out of a duramax like this guy on PT.net did - don't get me wrong, I LOVE overkill, but the ZF S6 conversion isn't what I was looking for.

As far as the shifter goes, it's going to be perfect. I fabricated my own shifter to go with the short throw shift kit I made. The position of the shifter isn't exactly where I want it yet, but I'm still tuning the short throw kit. Once I get that fine tuned I can put the center of the shift pattern to exactly where I want. I'll take some detailed pictures the next time I have it apart so you can see what I mean. You really need to see the front/rear view of the shifter to understand how it's placement works. For right now, a side shot is all I have:

Op you did a nice project kudos for that. But honestly the 4l80e is a better stronger transmission Than that. You did nothing wrong at all at stock power levels. Some hd silverados are stuck shift. But the 1tons etc were 80e auto trans. A used 80e with a shift kit can rollout 800# easy and hold 600hp fairly easy too. That's sorta hwy I went 80e. Plus turbos spool faster with auto.

I'm looking for a corvette. And I'm looking to put a 80e auto into it.

Thank you. In my opinion there's really no transmission that's strongest because my T56 is very far from stock and it has double the torque capacity than a stock T56...so we're really in the territory of transmissions that have been upgraded with aftermarket parts. Can a 4L60e or 4L80e be stronger than my T56? I'm sure it's possible, but an automatic is not for me. I really like your idea of making a corvette right for you by building it your way. If I was going to do an automatic in a corvette build then I'd put in a 6L80 transmission with a fully manual valve body and fabricate a pedal-shifter setup. The 6L80's are far stronger than the 4L60's and 4L80's off the showroom floor and with aftermarket upgrades they can be made to be bulletproof.

...
BTW, an auto shift is still a manual trans with ECM controlled clutch and shifting, and you can over ride it at any time with a push of a button.

I hear you loud and clear. If I had no choice besides an automatic it would be a manually shifted 6L80 setup with a fully manual valve body.

 

[M Hankel]

Thanks for the link to the calculator. A couple years ago I wrote a piece of software that I can plug in different values for tire size, transmission gear ratios, and rear end gear. It lets me see the tire speed, MPH, and engine RPM at any given RPM for all forward and reverse gears that the transmission has. I've now done auto-to-manual+tire-size swaps on my last two vehicles...I also swapped the rear end gear for my last truck too and the software is dead-on accurate. I only want to make a subtle change by going to a 4.10. If gas wasn't so expensive I'd be going to a 4.88 or 5. gear in the rear.

No worries man. Glad you're at least thinking about it. My tires are a tad over 32" tall so I'll be going with 5.13 gears with my T56 swap. I think the lower gear ratio will also help with clutch longevity since it will be much easier to get the thing moving from a dead stop. Thanks again for the clutch pedal and I'll be picking up that cross member from you as well.

Mike

 

[ThatDudeOrion]

So just to satisfy my curiosity, you left the shifter in the stock f-body location? You didn't have to source one of those ridiculously expensive mid-shift kits that moves the shifter forward on the trans to the inspection plate?

 

[M Hankel]

I don't know how often he checks this thread so I'll answer for him. Yes, stock Fbody shifter location. Some guys have done the conversion to move the shifter forward, but it's usually the pickup guys that don't have a center console and still have a bench seat so they need the extra clearance.

My T56 swap is coming up SOON!!!!

Mike

 

[ThatDudeOrion]

I don't know how often he checks this thread so I'll answer for him. Yes, stock Fbody shifter location. Some guys have done the conversion to move the shifter forward, but it's usually the pickup guys that don't have a center console and still have a bench seat so they need the extra clearance.

My T56 swap is coming up SOON!!!!

Mike

Oh ok, thanks Mike, that was one of the potential roadblocks I saw to doing this in my Esky and I'm glad it's not necessary. I noticed the company that made the mid-shift kits has gone bankrupt and nobody else makes them, so after seeing all the truck guys on pt.net use it, I was thinking I was stuck, until I found this thread. Now that rockland standard gear has the transfer case adapter and I don't need the mid-shift kit, I'm going to start acquiring parts to swap in a t56 if/when my trans dies.

 

[digitalfiend]

Oh ok, thanks Mike, that was one of the potential roadblocks I saw to doing this in my Esky and I'm glad it's not necessary. I noticed the company that made the mid-shift kits has gone bankrupt and nobody else makes them, so after seeing all the truck guys on pt.net use it, I was thinking I was stuck, until I found this thread. Now that rockland standard gear has the transfer case adapter and I don't need the mid-shift kit, I'm going to start acquiring parts to swap in a t56 if/when my trans dies.

Mike is absolutely right. I'm using the stock shifter location as indicated in the pictures in my first post. My T56 is attached to a stock F-body bell housing and is then attached to the engine as it normally would be. With my 2004's center console and the stock f-body shifter the alignment is almost perfect - it's like it was meant to go into our NBS trucks. Look at the pictures in my first post of the center console with the cup holders removed to see this. I'm not sure if it is easy to pick out, but I did put a couple slight bends in the mount for the shifter. This moved it just a little to the driver's side - if you're have some basic fabricating skills this shouldn't be difficult. I can get you some more pictures of the shifter if you need them, just let me know.

 

[992dr]

I'm in for updates.
I would love to do this to my NNBS.

Does anyone know how much of a difference is there between the NBS and the NNBS to complete this swap?

 

[ivin74]

What are the mpg's on the city and on the hwy on normal driving?

 

[Chevy305]

I'm in for updates.
I would love to do this to my NNBS.

Does anyone know how much of a difference is there between the NBS and the NNBS to complete this swap?

I have yet to see anyone do any conversions on the nnbs. I've searched on a few forums but only come up with empty threads with no answers. I'm sure it could be done but you'd most likely have to do some sort of custom work and have the wallet to afford it.

 

[992dr]

I have yet to see anyone do any conversions on the nnbs. I've searched on a few forums but only come up with empty threads with no answers. I'm sure it could be done but you'd most likely have to do some sort of custom work and have the wallet to afford it.

Same here, nothing worth while. 4l80e and 6l swaps but no manual swaps.

Its basically the same swap. Both trans are 4l60e. The only differences being DBW and DOD/AFM, correct?

Custom work doesn't bother me, driveshaft, trans mount, pedal assembly etc,,,. Its the tuning that gets me. The biggest investment would be the trans, sucks because I just saw a T56 sell for $700 on a local forum.

 

[Chevy305]

The tuning shouldn't be a problem with EFI Live or similar program. Unless you know a shop local, you'd probably have to send out your ECM to a professional tuner.

 

[M Hankel]

For the nnbs, the clutch pedal would be an obstacle for most people unless you have some fabrication skills. To my knowledge none of the nnbs rigs had a clutch pedal that'd bolt-in. The nbs trucks did, so the swap is pretty easy since the truck pedal assembly/hydraulics are a direct bolt-in deal.

Mike

 

[992dr]

The tuning shouldn't be a problem with EFI Live or similar program. Unless you know a shop local, you'd probably have to send out your ECM to a professional tuner.

So far, I've had pretty bad experiences with two local GM specific tuners. I'm going to another one about 3 hours away in late December.

For the nnbs, the clutch pedal would be an obstacle for most people unless you have some fabrication skills. To my knowledge none of the nnbs rigs had a clutch pedal that'd bolt-in. The nbs trucks did, so the swap is pretty easy since the truck pedal assembly/hydraulics are a direct bolt-in deal.

Mike

Thankfully I'm a welder/fabricator. I'll have to make my way to the local pick-n-pull to see if I can find a pedal assembly.

As much as I would love to do this, an 80e may be the way I'm going to go.
I'm going to have to do a lot of research.

How's your swap coming along?

Thanks for the info.

 

[Chevy305]

You can buy the whole pedal assembly from GM.

 

[992dr]

Do you have a part number for the assembly?

 

[M Hankel]

You can buy the whole pedal assembly from GM.

For an NBS, yes, and It's a direct bolt-in for a NBS suv. Will it work on a NNBS suv, I doubt it since I don't think the two share the same firewall and to my knowledge GM hasn't offered a manual trans in any of the full size GMT900 (NNBS) platforms . Plus the whole pedal assembly and bracket is plastic so It's not easy to modify like a metal assembly.

Mike

 

[YukonXL04]

Did some research, and apparently some mexico made V6 silverados came with a manual trans...

Also GM didnt stop in US until 08. So I would think maybe you could find it from a 07 truck.

Here ya go.
http://parts.nalleygmc.com/showAsse...el=14538&ukey_driveline=6218&ukey_trimLevel=0

See if that helps you NNBS guys

 

[992dr]

For an NBS, yes, and It's a direct bolt-in for a NBS suv. Will it work on a NNBS suv, I doubt it since I don't think the two share the same firewall and to my knowledge GM hasn't offered a manual trans in any of the full size GMT900 (NNBS) platforms . Plus the whole pedal assembly and bracket is plastic so It's not easy to modify like a metal assembly.

Mike

I wish it were that easy

Did some research, and apparently some mexico made V6 silverados came with a manual trans...

Also GM didnt stop in US until 08. So I would think maybe you could find it from a 07 truck.

Here ya go.
http://parts.nalleygmc.com/showAsse...el=14538&ukey_driveline=6218&ukey_trimLevel=0

See if that helps you NNBS guys

Ohhh my wish may have come true, haha

Thanks for the info. I appreciate it. I'm going to check it out

 

[M Hankel]

That link posted shows the same pedal/bracket I'm using for the NBS.

If the NNBS firewall looks like this, then you all are in luck.

Right where that red power cable goes into the firewall is where the hole gets cut for the master/pedal/bracket assy.

Mike