GearheadJoe

I had always assumed it is "impossible" to install a T5 5-speed in a C2 Corvette, since the T5 shifter is centered over the main shaft, and the C2 application requires that the shifter be moved over about 2.8 inches to match the C2 location for a Muncie transmission shifter.

In a recent thread on 5-speed and 6-speed C2 conversions, I learned from fellow CF member Tom Austin that there are some clever ways to install a T5 in a C2. Tom and several other members on the C3 forum have documented various methods in threads that go back to 2004. So, I amused myself reading through all those threads and I was fascinated by what I found. Unfortunately, the information is scattered around in about ten different threads and hundreds of postings. And, many of the photos that were posted in those old threads were hosted on outside servers such as tinypic.com and photobucket.com that are no longer accessible.

Even though I already have a TKO-600 in my C2, I thought the T5 conversion information was sufficiently interesting that I decided to try to compile, in a single document, all the information that I thought would be useful to others who might be interested in a T5 conversion for their C2.

The attached pdf document is my attempt to gather the information together in one place (with lots of data and photos!). It appears that there are several ways to complete a T5 installation for under $1000, which makes the T5 an interesting alternative to the $4000 cost of a TKO-600 kit.

If anyone reading this document has questions, corrections, or suggestions for additional material, please let me know. And, if anyone decides to pursue a T5 conversion in their C2, I'd like to stay in contact as they go through the process.

If I get useful feedback I will incorporate it and issue an updated version of the document.

Sky65

WOW!!!!!! Man that's a lot of work you put into that document. Well done.

Tom

GearheadJoe

Yes, it's hard to explain why I did this, since I already have a TKO-600 in my C2. However, sometimes a technical topic will grab my attention, and I enjoy doing the research.

I had a lot of fun trying to pull together all the information I found, and thought it was important to try to consolidate and preserve the information for other C2 owners who might be interested in doing a budget 5-speed conversion in the future. Most of the threads I reviewed are quite old, and I think the information is getting gradually lost.

And, the technical challenge that interests me the most is trying to figure out how to install a T5 in a C2 with no cutting of the tunnel. From the photos I found of existing C2 and C3 conversions, it appears that only some minor improvements would be necessary to achieve this goal.

Westlotorn

Joe thanks for your efforts, a 38 page read! You put a lot of effort into this project and great job gathering from so many sources.

I have 2 T5 transmissions in the garage, I was excited to do this conversion 5 years ago but cooled off as I worried about the Torque limitation.
I have driven cars with this tranny and they shift so smooth it is amazing and I really like the gear ratios in the Camaro V8 T5.
I have read about Gforce conversions with up to 600 ft torque ratings but that adds $2,000 to the cost.

Nice work.

Mark

Tom Austin

Mark,

Yes - Joe's efforts on this topic are EPIC! - thanks again Joe!!!

The real weakness that limits the torque rating of the T5's is the factory rear bearing retainer. In the link below you'll see how this part can be upgraded (the best $50 you'll ever spend to rebuild a T5). The Counter Gear Stabilizer that they designed greatly improves the durability of the T5 . . . I wouldn't be afraid of running a rebuilt T5 (with this exact part) in a C2 with a 300/350 HP small block. Make sure you check out the video!

https://www.5speeds.com/t5.htm

GearheadJoe

Yes, I have looked briefly at the G-Force gear set. It appears that you can buy the gearset (including a new mainshaft) for about $1500 at Jegs. I think I saw elsewhere that you can send your T5 to G-Force and they will install the gearset for you at a total cost (parts and labor) of about $2000.

Given that the all-in cost of a TKO-600 kit is about $4000, and the TKO-600 kit includes all the miscellaneous parts (shifter, rear mount, etc.), the cost gap between a T5 with the G-Force upgrades and the Silver Sport TKO-600 narrows to less than $2000. My guess is that the upgraded T5 would still be at least $1000 less than the TKO-600 kit, but the T5 installation will require more time for fabrication of things such as the shifter and rear mount. Some people would happily spend more of their time to save $1000, but people who have limited time might choose to just buy the TKO-600 kit.

Regarding the G-Force gear set, another thing I would want to check would be the possibility of increased gear noise. From the photos, it appears that one of the changes G-Force made to strengthen the gears was to reduce the angle of the gear teeth. This was the change that GM made between the Muncie M21 and the M22 "rock crusher." As I understand it, the rock crusher nickname came from the increased gear noise. So, the possibility of increased gear noise is something to look into when considering the purchase of a G-Force gearset.

As I described in the introduction of my article, if a person doesn't mind spending $4000 on a 5-speed, they might as well just buy the TKO-600 kit and be done with it. Aside from the lower cost of the T5, the only possible advantage that I can think of for the T5 is smoother shifting compared to the TKO-600. Personally, the TKO-600 shifting doesn't bother me, but I know that some people really object to it.

My sense is that real "sweet spot" for choosing a T5 over a TKO-600 is for applications under 400 HP, where the strength of the stock Camaro or Mustang gearset is adequate. This would be particularly true if I can figure out a way to install a T5 with no cutting of the transmission tunnel. In my article I describe two possible methods for achieving this, but these are just ideas that have not yet been shown to work.

Tom Austin

Joe,
I have the G-Force conversion in my T5 - and, yes, it's noisier than the standard T5 which I ran in my car for @ a year before I took it out and took it to them for the conversion. I don't really mind the extra noise - it's only objectionable when decelerating in 3rd actually. Plus - there is no extra noise in 5th - which is where I spend most of my time!

dplotkin

Sometimes a thing has just got to be done for the good of the many, especially when you can do it.

Thank you

Dan

GearheadJoe

Hi Tom:

Thanks, it's good to get some first-hand feedback on the question of gear noise.

When G-Force did the conversion for you, did you get back your old gear set? That might have some value to someone else if you have it.

One of the things I learned in my research is that when figuring out what T5 features you want, it can be useful to think of the gear set as a separate item, compared to other components such as the main case and the tailhousing. Your original Camaro gearset could be installed into almost any WC T5 main case (even one from a V6 T5), and then be combined with a tailhousing from almost any WC T5. There are lots of Chevy V6 T5 transmissions around, but the GM V6 gear sets are weaker and should not be used with a V8 engine.

To my knowledge, though, the Chevy V6 and V8 main cases are the exact same part. I have heard that for some reason, the Chevy 4-cylinder T5 used a smaller front main bearing, so the 4-cylinder main case is not quite the same as the one used for the V6 and V8.

Tom Austin

Hi Joe,

Unfortunately, no - I did not get my old gear set back . . . I never even thought about asking for it!

Tom

karkrafter

Bravo!

66vette2

Here is what I did with the T-5. Installed with the bell-housing attached. Used original bell-housing and transmission mount. No cutting of the tunnel, Kept the tunnel insulation. Pictured with the Muncie next to the T-5. This was an interesting Project.

GearheadJoe

Wow, I had to study that photo for several minutes to try to figure out how it works!

I gather that the rectangular aluminum block in the center (containing the four allen-head screws) is responsible for coupling the fore and aft travel of the two external shifter control rods, and the link to the right of it is responsible for rotating the upper (T5) shifter control rod. Is that correct?

I'd be interested to hear more about why you decided to take on a project of this size rather than just buy a TKO-600 kit. Was it because you prefer the smoothness of the T5 shifting?

I've sketched out a possible design for a shifter that exits the side of the existing T5 shifter box on the tailhousing, but I don't yet know whether it will work as expected. I hope to prototype it over the next few weeks.

Tom Austin

WHOA!!!!!!!!!!!!!!!!!!!!!!!!!! . . . that's absolutely amazing!!! How did you do that??? The shifting mecanism looks complicated - did you design it/make it? . . . or, is it readily available somewhere?

Tom

66vette2

Your exactly correct on the mechanism. I like to piddle on my car. Wanted to see if I could do it. i was not aware of the shifting difference of the two transmissions. It was fun to do. However, I did not realize that I would have to pull the transmission out four times to dial it in.

66vette2

It is not that complicated if you look at it. I designed and fabricated the parts. That is my design it is not available. Kept my ash tray, transmission mounts to original location, kept-ed the tunnel insulation and cutting of the tunnel etc.. Also, it can be installed without moving the engine or loosening the bell housing,

Westlotorn

Not sure how you did it but that conversion is pretty slick. How does it shift?

66vette2

Once I got it dialed in, it shifted perfect. The weather has set in. The toys have limited drive time. Looking forward to test drive again soon.

GearheadJoe

This post is an update to my original post back in November about installing a T5 5-speed in a C2 Corvette. Ever since the Covid-19 lockdown started, I have had more time at home to amuse myself with projects that interest me. So, I have continued to think further about possible T5-C2 conversion strategies and investigate the options that look promising. My overall goals for this project are two-fold:

1) Develop a complete solution for a pure bolt-in T5 conversion that requires no cutting of the transmission tunnel and no modifications to the crossmember

2) Keep the total cost of the parts under $1000

Of the many options described in my November article, I have decided to pursue a solution that uses an adapter plate to mate a Mustang T5 to the stock C2 bellhousing. This allows the owner to retain their existing bellhousing and clutch linkage.

People who have followed this discussion may recall that a key ingredient of the solution used by Tom Austin was to use a 1983 Camaro bellhousing that tilts the T5 19 degrees to make the shifter come out in almost the right location for a C2 Corvette. These tilted bellhousings are a bit rare and typically cost about $300 on ebay, and they require some modifications to the C2 clutch linkage. In view of this, I decided to pursue using an adapter plate that preserves the stock C2 bellhousing and stock C2 clutch linkage.

The photos below show the first prototype of my proposed adapter plate that I just got back from the machinist. When looking at the side that faces the T5, the four large holes are the ones that attach to the stock C2 bellhousing, and the four small holes (not yet threaded) attach to the Mustang T5 main case. I had to limit the rotation of the Mustang T5 to 18.5 degrees due to the conflict between one of the bellhousing bolt holes and one of the Mustang T5 bolt holes, as seen in the lower right corner.

In quantities of 10, this adapter plate can be made for under $200.

The only other major component that needs to be worked out is a shifter that is modified to fit with no cutting of the tunnel. I think I have that worked out too, but want to do a test-fit to confirm that works. There are several smaller problems such as the rear mount and the mechanical speedometer output, but I think I have these worked out.

Over the next couple of months I hope to develop a complete solution and test-fit it in my own car. Once I feel that I have a proven solution, I will post a complete documentation package.

GearheadJoe

This is just a quick update to let people know that I am still working on my T5-in-a-C2 bolt-in solution, but progress has been slow due to other priorities.

Attached is a short article I wrote recently for my NCRS chapter newsletter. The article describes the main problem (shifter placement), and summarizes the specific strategy that I have selected to prototype and test.

There are seemingly dozens of strategies that can be used to create a bolt-in T5 solution for a C2 (or C1/C3, I believe), but I have settled on one specific approach that I think is the simplest and lowest cost strategy. The key ingredients are a suitable adapter plate that mates to a stock C2 bellhousing, a T5 from a Mustang, and a shifter from Modern Driveline. Then there are several smaller tasks related to details such as a mechanical speedometer drive and a rear transmission mount.

I'm pretty far along with the adapter plate, shifter, and speedometer drive but I'm still sorting out some details with the rear transmission mount and driveshaft. If I can get this to work, I think it will provide a low-cost option for people who want a bolt-in 5-speed transmission for their C2.