Wow, a t-56 swap is really expensive! I remember (a couple of years ago) seeing just the tranny go for $500.. Now you would be lucky to get one for a grand! Anyway, I'm changing the direction i'm taking my Iroc from street/strip to daily driver/commuter. Basically the only way i will get to keep my car (wife - I have a motorcycle and that's the only vehicle toy i'm allowed.. lol). With my current setup, i am getting like 15 mpg (750cfm holly, 700r4, 3.73 posi). When i had 2.73 open in the rear, i was getting around 24mpg (everything else was the same). So, i'm going to build a 2.73 and put that in the car (probably will sell the 3.73 rearend.. has less than 1000 miles on it so i hope i can get something for it).

Now i'm looking to do a t-5 swap if it will work out. The questions i have are where can i get a rebuild kit for a 1987 t-5 (have one from a v6 car that is locked in 1st gear), and can i swap in a different 5th gear? Specifically one with a .61 or .63 ratio? I just want to know if it is possible so i can hunt how the gears i need.. I wont get quite as good of mileage as i would with t-56's awesome .50 6th gear, but the money saved in doing a t-5 swap would be more than worth it for me..

Thanks

 

a t5 from a 6 cyl car will not work

 

A t-5 tranny would work there are some after market bellhousings that will boltup together.

 

actually, yes it will. You just need the correct clutch/flywheel. I would have to ask my father-in-law to be specific (he did it a few years ago for my now wife's camaro), but IIRC the bellhousing for the v6 t-5 and a v8 t-5 are the same. In any case, i have the bellhousing, clutch, and flywheel he used (clutch is toast, but i would know what to get). The only difference i can see is the 10 spline vs the 27 spline. Is there any major advantage between the two?

 

You are close, the GM V8's clutches are 26 spline (Ford T5's are 27). The V6 clutches are 14 spline, not 10. 26 splines would typically be stronger than 14, but I doubt the 14 splines would ever be the weakest link in a T5 drivetrain. You will have to check if the clutch will bolt to the V8 flywheel, as the V6 clutch is a smaller diameter. The V6 T5's have a very deep 1st gear and a bigger RPM drop going into 2nd than the V8 models. Not the end of the world, especially if you are putting highway gears back in the car, the low 1st gear may help you get out of the hole.

Edit: I did a little checking and parts stores sell 14 and 10 spline clutches for V6 cars. I thought they were all 14 splines.

 

heh, at least i wasnt totally out in left field with my numbers. If all else fails, i have a clutch and flywheel that my father-in-law used here, and i can call him if i have questions. I found that i can get a gear set for 5th gear for about $190 brand new that would give me a .59 ratio.. that sound too bad for price? And the rebuild kit i found would be about $180, tho i dont know what all is in it..

 

So....

That's how much you're going to have to spend for a weenie 6-cyl trans with the undesirable gears; plus a 5th gear; plus a kit; plus a special "downgrade" clutch?

Then when you get all done, you'll have something you'll HATE, like everybody else that's done it because they thought it was a good idea (for why I can't yet grasp), which you will be UNABLE TO WAIT to jerk out and put something reasonable in it, which won't have got any cheeeeper in the meantime, assuming it doesn't tear up before you get so sick of it you can't stand it for one more minute. What you'll end up with, is driving around 100% of the time wishing you had at least one more gear in every gap between the gears that crap transmission has. Every shift, it'll go from "screeeem" to "luuuuggggg", with nothing available in between.

.59 5th + 2.73 rear gears + 55 mph = 1100-1150 RPM. To put that in perspective, go out to your car right now, put it in 4th gear, and go up a hill at 25 mph. That'll give you a full load at about 1150-1200 RPM. If that's what you want your driving experience to be like 100% of the time, then THAT'S the gear combo for you.

Can you explain to your wife how this is a good idea?

A "rebuild kit" has the soft/wear parts that you need when you tear one down and put it back together. Bearings, snap rings, shims, selective-fit snap rings, an O-ring or 2, maybe a tubular-style gasket, maybe an extension housing bushing. I don't think it has the Torrington that goes between the clutch gear and the mainshaft, but it might. No gears or shafts or anything like that. No blocker rings, keys, forks, fork pads, or any of the other small parts like that, that wear out but aren't part of the neccessary R&R stuff.

In case you can't tell, I'd suggest not doing that to your car.

 

thanks for the input

I've driven a v8 with a v6 t5 - not as big of a deal as you make it out to be between gears, trust me. Fortunately for me, when trying to go up a hill in 5th, i've got this neat little peddle that allows me to put the car in 4th . Ever driven an underpowered 4cyl with a 5speed? Gotta do that every damn time you go up a hill, pass, or do any kind of acceleration anyway, so im not too awful worried about it.

If i dont like it, there will always be my 700r4 to put back in if i have to. If it tears up, then i can go that route also. But it comes down to getting a bit better mileage (i have to drive about 500 miles a week for work and school) and not spending $2k+ to do so. To make it worth the cost of a T-56 swap, i would need to drive my car only (not my bike at all during the warmer months) while commuting for a good 7 years in when you would compare the possible mileage with i could squeeze out of my car with a 700r4 or a t-56. As i stated before, i was consistently getting around 24mpg with my 700r4. I would hope i could get up to about 28mpg with a t-56 swap, so about 26mpg with this t-5 swap would be good because i would get over the 25mpg "hump".

Either i make this car a viable commuter, or the wife is going to make me get rid of it for another car (we are currently with one car now and need a second - so if I make my camaro good enough to commute in, i get to keep her.. otherwise, bye bye Iroc).

 

thank you, dang sofakingom is f*****g rude.

 

I'd prefer not to think of it not so much as that I'm rude, but rather, that the un-candy-coated truth is painful. But that's just me, I'm not bright enough to do anything BUT tell the truth, I'm not smart enough to make stuff up or figure out ways to slide it in easy. Gotta stick with the facts. I'm not a salesman. I'm REAL STUPID. Because of that, I tend to just tell it like it is.

But yeah, if you can live with (a) the idea of driving a car like that, and (b) spending extra money to get what most of us spend money to get rid of, then I guess you should go ahead and do it. Problem is, after you get done with that, it won't be an "IROC" any more, it'll be an IROC shell that's been ..... well, something-ed. But in the end, that's OK, it's your car and you can do it, just don't say you weren't warned. Or, don't be too surprised if it turns out not to achieve the ultimate goal of keeping the domestic peace and you have to sell it anyway and nobody else will touch it with a 10-foot pole because it's so un-IROC-like driving.

 

oh ****, you're right! i'm more worried about having a true iroc than i am being happy with my car! I better get on that!

 

yeah, nobody really wants to be happy with there car right.


oh and as far as telling it how it is why not try being more helpful than rude why not try 90 percent helpful and ten percent rude instead of the other way around.
----------


see, helpful but not rude

 

While he might be uncouth, sofakingdom is very knowledgeable about T5's, having swapped about ten of them in his thirdgen. And I agree with him. A V6 T5 is not a good idea behind a V8 engine.

 

haa leave the 373 rear with the t5 it will be better on gas