Tremec T-56 Six Speed into a C2
03-28-2002, 03:37 PM
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Tremec T-56 Six Speed into a C2
I am just finishing the cosmetic details from having a T-56 six speed installed in my ’66. The transmission is working beautifully but the saga of getting it installed is not for the faint of heart.
I chose the T-56 because it appears to be the new standard high performance transmission. It is used in Vipers, Vettes, Camaros, Cobra Mustangs and a handful of other platforms. It is a stout, quiet, smooth shifting box. Tremec now makes an aftermarket version that includes an adapter plate that mates the T-56 right up to the Muncie style bellhousing. No change is required to the mechanical clutch linkage on the C2. The transmission also has a mechanical speedometer mount, just plug in the speedo gear from the Muncie and screw in the cable. Sounds easy? Read on……
The first step was cutting out the center section of the Vette’s transmission cross member. (Don’t panic numbers matching junkies, my Vette is a non-numbers matching car with a 350 ci motor and one piece fiberglass front end. I rescued it from a twenty something year old student who was being crushed under the expense of keeping it on the road.) With the center section removed, we were able to bolt up the transmission to the motor and see how the trannie fit. The T-56 is a huge box compared to the Muncie, although the shift linkage is internal on the T-56 so there is nothing hanging off the side of the case. We jacked the T-56 up into the transmission tunnel as far as it would go and started looking at the angle the driveshaft made with the output of the transmission and the rear end. We didn’t like what we saw and, after talking to some driveline specialists, we decided the transmission needed to go up another half inch or so. This would give us a driveshaft angle of 2 degrees out of the trannie, and 2 degrees at the rear end.
Of course this meant we needed to cut the transmission tunnel. However, the corvette dash, with its center section, sits in the way. The gauges needed R and R anyhow, and the dash was in need of a new paint job. So off came the trim, the side rivets were drilled, the steering column was pulled, the instrument cluster removed, and the bolts at the windshield were removed and, voila, out came the dash. The good news about the corvette transmission tunnel is the top is flat (in one dimension), so fabricating a new cover is relatively straightforward.
The hole was cut in the tunnel and the transmission was jacked up to the correct position. (One more item, the Tremec shifter comes up in the center of the console and sits about 2 inches aft of the stock shifter location. So the console needs modification also.) The transmission looked great in the correct position, an aluminum cover was fabbed for the transmission tunnel and then glued and riveted into place. Underneath, a removable cross member was made. And while we were under there, a new exhaust system was welded up. It included Hooker Super Comp headers to 2.5 inch mandrel bent tubes, into a Dr Gas X pipe, and then out the back through Dynomax super turbo mufflers.
Up top, the newly painted dash was reinstalled (the center section had to be shortened to accommodate the higher transmission tunnel). All the rivets were replaced with nut inserts, so taking the dash out again is just a matter of unbolting. The reconditioned instrument cluster was dropped in, the center console was modified for the new shifter location, and a cover plate was fabbed with a leather boot.
I know I’m leaving out many of the details, but I’d thought I’d get this out to the forum for history on transmission swaps.
I chose the T-56 because it appears to be the new standard high performance transmission. It is used in Vipers, Vettes, Camaros, Cobra Mustangs and a handful of other platforms. It is a stout, quiet, smooth shifting box. Tremec now makes an aftermarket version that includes an adapter plate that mates the T-56 right up to the Muncie style bellhousing. No change is required to the mechanical clutch linkage on the C2. The transmission also has a mechanical speedometer mount, just plug in the speedo gear from the Muncie and screw in the cable. Sounds easy? Read on……
The first step was cutting out the center section of the Vette’s transmission cross member. (Don’t panic numbers matching junkies, my Vette is a non-numbers matching car with a 350 ci motor and one piece fiberglass front end. I rescued it from a twenty something year old student who was being crushed under the expense of keeping it on the road.) With the center section removed, we were able to bolt up the transmission to the motor and see how the trannie fit. The T-56 is a huge box compared to the Muncie, although the shift linkage is internal on the T-56 so there is nothing hanging off the side of the case. We jacked the T-56 up into the transmission tunnel as far as it would go and started looking at the angle the driveshaft made with the output of the transmission and the rear end. We didn’t like what we saw and, after talking to some driveline specialists, we decided the transmission needed to go up another half inch or so. This would give us a driveshaft angle of 2 degrees out of the trannie, and 2 degrees at the rear end.
Of course this meant we needed to cut the transmission tunnel. However, the corvette dash, with its center section, sits in the way. The gauges needed R and R anyhow, and the dash was in need of a new paint job. So off came the trim, the side rivets were drilled, the steering column was pulled, the instrument cluster removed, and the bolts at the windshield were removed and, voila, out came the dash. The good news about the corvette transmission tunnel is the top is flat (in one dimension), so fabricating a new cover is relatively straightforward.
The hole was cut in the tunnel and the transmission was jacked up to the correct position. (One more item, the Tremec shifter comes up in the center of the console and sits about 2 inches aft of the stock shifter location. So the console needs modification also.) The transmission looked great in the correct position, an aluminum cover was fabbed for the transmission tunnel and then glued and riveted into place. Underneath, a removable cross member was made. And while we were under there, a new exhaust system was welded up. It included Hooker Super Comp headers to 2.5 inch mandrel bent tubes, into a Dr Gas X pipe, and then out the back through Dynomax super turbo mufflers.
Up top, the newly painted dash was reinstalled (the center section had to be shortened to accommodate the higher transmission tunnel). All the rivets were replaced with nut inserts, so taking the dash out again is just a matter of unbolting. The reconditioned instrument cluster was dropped in, the center console was modified for the new shifter location, and a cover plate was fabbed with a leather boot.
I know I’m leaving out many of the details, but I’d thought I’d get this out to the forum for history on transmission swaps.
03-28-2002, 04:20 PM
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Re: Tremec T-56 Six Speed into a C2 (Cris)
Of course this meant we needed to cut the transmission tunnel. However, the corvette dash, with its center section, sits in the way.
this swap. However, I thought I saw a post once from MassVette indicating
that the Richmond six spd will fit without hacking the actual dash.
[Modified by Crazyhorse, 3:33 PM 3/28/2002]
03-28-2002, 07:22 PM
#3
Melting Slicks
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Re: Tremec T-56 Six Speed into a C2 (Crazyhorse)
I did a 5 Speed into a 66 and I am not sure I would undertake that again. This Tremic swap sounds like drilling your own cavities without and novacane! Even the Richmond, although fun once done, is a hummer to get in the car. The tremic sounds like the interior surgery is as big a deal as the under car if not worse..
03-28-2002, 08:44 PM
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Re: Tremec T-56 Six Speed into a C2 (66 SC'ED VETTE)
You guys are right. This transmission is not the perfect aftermarket swap for a C2. The Tremec TKO has similar problems. I must say, now that I've lived through the pain of putting it in, 6 gears with 2 overdrives is nice.
03-28-2002, 11:59 PM
#6
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Re: Tremec T-56 Six Speed into a C2 (Cris)
Cris,
Great job and thanks for the write-up! If you can post some pictures (as 66 SC'ED requested), I think we would all appreciate it even greater.
Thanks again,
Great job and thanks for the write-up! If you can post some pictures (as 66 SC'ED requested), I think we would all appreciate it even greater.
Thanks again,
03-29-2002, 12:31 AM
#7
Re: Tremec T-56 Six Speed into a C2 (Cris)
I've been aware of T56/C2 clearence issues for some time, in fact several of us around here have been holding our breathe for a volunteer to step forward to execute & document a C2/Tremec TKO swap, but apparently none of us want to be the guinea pig :nonod: . Plenty of documented C3, Camaro, Chevelle, Mustang etc. TKO swaps but none into a C2 yet (that I'm aware of).
BTW the C3 isn't really comparable...they revamped the firewall and expanded the tunnel to accomodate the new Turbo 350/400's. It's tough enough for most C2 owners to accept the fact they'll have to (for all practical purposes without pulling the motor) cut/butcher their crossmember for any of the current overdrive solutions (T56/TKO/ROD), I can't imagine most will consider the mod's you required :eek:
BTW, did any of you consider shimming/angling the rear carrier to match the critical plane/angle of the trans output rather than cutting the tunnel to level the T56 in order to meet the carrier's plane/angle ? (if thats even possible) just wondering.
[Modified by Viking427, 10:47 PM 3/28/2002]
BTW the C3 isn't really comparable...they revamped the firewall and expanded the tunnel to accomodate the new Turbo 350/400's. It's tough enough for most C2 owners to accept the fact they'll have to (for all practical purposes without pulling the motor) cut/butcher their crossmember for any of the current overdrive solutions (T56/TKO/ROD), I can't imagine most will consider the mod's you required :eek:
BTW, did any of you consider shimming/angling the rear carrier to match the critical plane/angle of the trans output rather than cutting the tunnel to level the T56 in order to meet the carrier's plane/angle ? (if thats even possible) just wondering.
[Modified by Viking427, 10:47 PM 3/28/2002]
03-29-2002, 12:36 AM
#8
Melting Slicks
Re: Tremec T-56 Six Speed into a C2 (Viking427)
Is a Richmond FIVE speed an easier swap? I'm sort of thinking one OD gear would be plenty for most of my driving. Seems like I've read this one is pretty straightforward and reasily reversable.
03-29-2002, 12:53 PM
#10
Re: Tremec T-56 Six Speed into a C2 (62fuelie)
Anyone tried a Gear Vendors Overdrive behind the Muncie? A couple of grand sounds cheap compared to the work required to get a larger gearbox installed...
03-29-2002, 01:51 PM
#11
Melting Slicks
Re: Tremec T-56 Six Speed into a C2 (62fuelie)
Ed,
We installed the Richmond 5-speed in a 67. We did have to make a new trans. cross-member but did not have to modify the tunnel or console. We made the new removeable cross-member to make installation and removal easier. The shifter comes up exactly in the original location.
MassVette is finishing the installation of a Richmond 6-speed (I'm not sure which model) in his 67 and will be posting the details soon. From what he has said it worked out well without changing the trans. tunnel or cross-member.
Rich Lagasse
We installed the Richmond 5-speed in a 67. We did have to make a new trans. cross-member but did not have to modify the tunnel or console. We made the new removeable cross-member to make installation and removal easier. The shifter comes up exactly in the original location.
MassVette is finishing the installation of a Richmond 6-speed (I'm not sure which model) in his 67 and will be posting the details soon. From what he has said it worked out well without changing the trans. tunnel or cross-member.
Rich Lagasse
03-29-2002, 03:59 PM
#12
Team Owner
Re: Tremec T-56 Six Speed into a C2 (richscorvettes)
:cool: Swap. I had a T56 in my 94 Z28 and loved it. Want to see pics of the swap..
The Richmand 5 speed has a lower first and no ovderive. The Richmond six speed has one overdrive.
[Modified by 93Polo, 2:59 PM 3/29/2002]
The Richmand 5 speed has a lower first and no ovderive. The Richmond six speed has one overdrive.
[Modified by 93Polo, 2:59 PM 3/29/2002]
03-29-2002, 04:11 PM
#13
Instructor
Re: Tremec T-56 Six Speed into a C2 (Cris)
The Richmond 5-speed can be fit without ANY permanent modifications to a C2. You only need to fabricate a new trans. mount to crossmember plate. It's not too easy, but it can be done.
03-29-2002, 09:28 PM
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Re: Tremec T-56 Six Speed into a C2 (Viking427)
Sorry I don't have any pictures. The real information is a shot under the car and I lost access to a lift. I will post some pictures as soon as I get them (I'll need help, I'm an electrical engineer, but still can't figure out all this computer stuff). The car looks very slick underneath - too bad nobody sees it. If any of you are in the San Jose area, I'd be happy to meet with you.
Viking: We had passing thoughts of rotating the rear end angle, but we also did not like how low the trannie sat in the car without the transmission tunnel surgery. Out came the saws....
My research found three people who had done the T-56 swap in a C2. Their swap, however, was a complete LT1 motor and drivetrain. The late version of the T-56 uses a hydraulic clutch and has a shorter bellhousing. None of the three said they had to go into the transmission tunnel. I did call one of the guys while we were fitting the T-56 in my car. I think he let his box sit a little lower than mine.
I do think the ROD 6 is a better mechanical fit in the car, but kept getting mixed reviews on the performance. I heard nothing but glowing reviews on the T-56. The T-56 does work well, but there was a price to pay.
Viking: We had passing thoughts of rotating the rear end angle, but we also did not like how low the trannie sat in the car without the transmission tunnel surgery. Out came the saws....
My research found three people who had done the T-56 swap in a C2. Their swap, however, was a complete LT1 motor and drivetrain. The late version of the T-56 uses a hydraulic clutch and has a shorter bellhousing. None of the three said they had to go into the transmission tunnel. I did call one of the guys while we were fitting the T-56 in my car. I think he let his box sit a little lower than mine.
I do think the ROD 6 is a better mechanical fit in the car, but kept getting mixed reviews on the performance. I heard nothing but glowing reviews on the T-56. The T-56 does work well, but there was a price to pay.
03-29-2002, 11:40 PM
#15
Instructor
Re: Tremec T-56 Six Speed into a C2 (Cris)
Hey Cris
We put a T56 in 67 behind a 502/502, 4:11 rear end. We did very min, mods. The tunnel was modified only enough to accomadate the new shifter location. We did make the cross member removable, it could have been avoided, but you wouldn't be able to pull the tranny without pulling the engine if the cross member was left as a one piece.
As far as the drive shaft angle we kept our's the same as stock, we made a drive shaft angle jig before we pulled the Munice, then matched it up to the T56. I don't have any concerns about the tranny sitting to low in chasiss. The car runs like a bear, 2000 rpm 90mph 6th. We put 5,000 miles on it in 10 weeks. First, second gear come on real fast you better know how to shift in a hurry. The car is a bast to to drive with the 6 speed.
If any wants Pic's I'll send them email I don't now how to post them here.
Thanks Cole
We put a T56 in 67 behind a 502/502, 4:11 rear end. We did very min, mods. The tunnel was modified only enough to accomadate the new shifter location. We did make the cross member removable, it could have been avoided, but you wouldn't be able to pull the tranny without pulling the engine if the cross member was left as a one piece.
As far as the drive shaft angle we kept our's the same as stock, we made a drive shaft angle jig before we pulled the Munice, then matched it up to the T56. I don't have any concerns about the tranny sitting to low in chasiss. The car runs like a bear, 2000 rpm 90mph 6th. We put 5,000 miles on it in 10 weeks. First, second gear come on real fast you better know how to shift in a hurry. The car is a bast to to drive with the 6 speed.
If any wants Pic's I'll send them email I don't now how to post them here.
Thanks Cole
03-31-2002, 01:34 AM
#18
Re: Tremec T-56 Six Speed into a C2 (Cris)
JungleBoy,
Theres been some past mention of using Gear Vendors Overdrive unit as an overdrive solution. 1st problem is the price, the GVOD units that replace tailhousings (model # 3DM21 for Muncies or 3DT10 for T10's) start at $2400 and up. Entire factory new overdrive transmissions cost roughly $2300 (aftermarket T56's, and 3550-TKO's) with salvage yard OEM T56's (94-97 F-body) units running much cheaper. Richmond's ROD costs roughly $2800.
The second issue is again the tunnel fit, the C2 tunnel tapers down to a pretty narrow spec. above & behind the crossmember, so much so that some larger trans output yokes won't even clear the tunnel top/sides, let alone a trans tailhousing with a larger dia. than a Sam's club Folgers coffee can. Another problem (personel preference) is it's only available in a 22% reduction.
For frequent street duty I consider Richmond's 6-speed (ROD), Tremec's 3550 (TKO) and T56 (OEM and Aftermarket) as the only true overdrive options out there right now. As mentioned, Richmond's venerable 5 speed is not a true overdrive since 5th is still 1:1 just like the Muncie, requiring 2:56 rear gears to bring highway rpms down to a tolerable level (Disclaimer: I consider "modern" highway speeds 70-80mph, compared to 55mph of yesteryear, and a nice tolerable cruise RPM ~ 1800-2200 rpm...sidepipes :rolleyes: ). Another alternative for those who want an exact retro-fit with zero headaches and near OEM appearences is an "ultra-wide" 4-speed like the BW's T10 "Z" ratio (3.42/2.28/1.46/1.00) with 2.32 or 2.56 rear gears, or G-force's G-101 overdrive 4th gear ratios (www.g-forcetransmissions.com/pdfs/G101_ratio.pdf) with slightly higher rear gears of 2.73 - 3.08. Here's a nice link to crunch your own combo's; http://www.angelfire.com/fl/procrastination/rear.html
Theres been some past mention of using Gear Vendors Overdrive unit as an overdrive solution. 1st problem is the price, the GVOD units that replace tailhousings (model # 3DM21 for Muncies or 3DT10 for T10's) start at $2400 and up. Entire factory new overdrive transmissions cost roughly $2300 (aftermarket T56's, and 3550-TKO's) with salvage yard OEM T56's (94-97 F-body) units running much cheaper. Richmond's ROD costs roughly $2800.
The second issue is again the tunnel fit, the C2 tunnel tapers down to a pretty narrow spec. above & behind the crossmember, so much so that some larger trans output yokes won't even clear the tunnel top/sides, let alone a trans tailhousing with a larger dia. than a Sam's club Folgers coffee can. Another problem (personel preference) is it's only available in a 22% reduction.
For frequent street duty I consider Richmond's 6-speed (ROD), Tremec's 3550 (TKO) and T56 (OEM and Aftermarket) as the only true overdrive options out there right now. As mentioned, Richmond's venerable 5 speed is not a true overdrive since 5th is still 1:1 just like the Muncie, requiring 2:56 rear gears to bring highway rpms down to a tolerable level (Disclaimer: I consider "modern" highway speeds 70-80mph, compared to 55mph of yesteryear, and a nice tolerable cruise RPM ~ 1800-2200 rpm...sidepipes :rolleyes: ). Another alternative for those who want an exact retro-fit with zero headaches and near OEM appearences is an "ultra-wide" 4-speed like the BW's T10 "Z" ratio (3.42/2.28/1.46/1.00) with 2.32 or 2.56 rear gears, or G-force's G-101 overdrive 4th gear ratios (www.g-forcetransmissions.com/pdfs/G101_ratio.pdf) with slightly higher rear gears of 2.73 - 3.08. Here's a nice link to crunch your own combo's; http://www.angelfire.com/fl/procrastination/rear.html
03-31-2002, 01:49 AM
#19
Melting Slicks
Re: Tremec T-56 Six Speed into a C2 (Viking427)
Certainly some useful options. I had thought I had read somewhere that the Richmond 5 sp. could be had with a large variety of optional ratios, including >1:1 for 5th. Anyway, the idea of a very wide ratio 4sp w/ a long legged rear end makes a lot of sense. It would be interesting to drive a car so equipped to get the feel of it.
03-31-2002, 10:44 AM
#20
Melting Slicks
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Re: Tremec T-56 Six Speed into a C2 (62fuelie)
Richmond does support changing ratios in the 5 Speed. You just remove the gear from the counter shaft and the gear from the main shaft by removing snap rings. Switch in a corresponding set of gears for another ration and you are on your way.
I don't think this can be done to achieve overdrive 5th in the 5 Speed however.
I don't think this can be done to achieve overdrive 5th in the 5 Speed however.