OK, a T5 looks to be in future. My car is more of a driver than a racer, and with the cost difference factored in, the T5 decision has been made. I DO have some questions though on what to look for.

First, it's gotta be a V8 Fbody car right? The offset and input shafts are specific to V8 F-bods so I've been told.

Second, World Class T5s are from 86 and up? Can anyone confirm this?

Third, what year did the Birds go from mechanical speedo to electronic? Cammie's changed in 90, right? What's involved in swapping to a cable driven speedo if I find an electronic donor?

Fourth, gearing. Z28, and Irocs got a closer ratio T5 correct? What about Birds? ....and is the difference really a big deal? I'm going to be running a 3.70 gear, and currently I'm running a 3.27. Even my mildly built L98 should render any difference in gearing pretty much moot. Any opinions? Again, this is a street car. Timeslips aren't really a concern.

I've found partial answers here and there, but I figured this thread should pretty much sum up all my concerns.

Thanks for the help guys.

 

Yup, V8 F-body only.

87-up or 88-up. 86 was definitely still 1st design.

They interchange directly; one little screw.

Yes, the better cars got the better gears; 5th is the main difference. You want the better (closer ratio) version, with the .73:1 5th. The .6whatever (TBI version) is too steep; it always feels like you need a 4½th gear. 5th is too much for going up a hill, but 4th is too big of a change. Especially with all that gear and a L98 (TPI motor); 4th cruising down the highway is almost the top of its power band (4000 RPM @80). AFAIK as long as you stick with the trans from a TPI car, and make sure it's 2nd design, you'll get the better gears.

1st design (top) vs 2nd design:

 

So the 2nd picture is the world class? (just to clarify)

....as far as the gearing, here was my logic: I figured 5th gear was mostly for highway cruising, so a little taller gear would be better, even if it was a little far from 4th gear. As for first, I figured the difference wasn't enough to worry about, even if it's a little toooo steep with the wider ratio.

....but you're saying differently, eh? Hmmmm. Any other opinions on the different ratios?

BTW, thanks for the input Sofa!

 

Right, the 2nd pic is the 2nd design.

AFAIK all of the V8 transmissions have the same ratios 1st - 4th (2.95 1st); but I could be wrong. The only one I've seen different is 5th, and it's either .73 or .63 depending on whether it's the higher-perf (LB9/L69) or low-perf (L03/LG4) version.

I accidentally put a .63 gear set fifth in mine one of the dozens of times I rebuilt a T-5 (maybe it was in better shape or something); I hated it so bad I took it back out, tore it down, and put back the .73 that belonged in it. Like I said, it always seemed like there needed to be a gear in between; I couldn't pass anybody in 5th on the highway easily, especially going uphill, and going down to 4th was a HUGE jump in RPMs. It was awful.

Just MHO, others may feel otherwise. You might feel more impelled than me to get it how you want it the first time, I don't know if changing them back and forth is as realtively trivial for you as for me though.

 

No, no, I hope to do this once. Well, nothing is forever, but you know what I mean.

Hmmmmmm. What's the 4th gear ratio? I wasn't concerned with which gearset I got, but now I'm reconsidering.

....how can you tell once it's outta the car?

...and thanks again for the advice!!

 

4th is the 2 shafts coupled together; exactly 1:1.

 

The RS version appealed to me also because of the .63 fifth gear for lower cruising rpm's, but just about every post I've read where people have tried both say they preferred the .73 fifth gear. I ended up getting the Iroc/Trans Am .73 version. It's rumored that some of the late 87 cars got the WC T-5, but as long as you stick with 88-92 T-5's, they're all the better ones. While shopping for one, the most crucial thing to check is the numbers on the metal i.d. tag. Go to 5speeds.com and click on their T-5 section. There's a trans tag i.d. chart on there that will tell you if a T-5 is a WC or non-WC by the i.d. tag#. I wouldn't buy any T-5 unless the seller can give you the i.d. tag number. A lot of guys have stuck non-WC trannys in the newer cars for temporary fixes. Some even put a lousy V-6 version in to get them by, so make sure to get the numbers before you buy. And like Sofa already said, the mechanical speedo bullet directly replaces the electric VSS unit in the tailshaft housing. BTW, the V-8 T-5's all have a 28 spline input shaft, all V-6 T-5's have a 14 spline input.

 

Thanks for the info guys.

I'm still not sure about which 5th gear to look for. The lower RPMs for cruising sounds pretty appealing, but I know how my 700 feels in OD. If I don't get on it enough to downshift, it's pretty sluggish as is, and that's the pretty much the same as the close ratio/Iroc gearing. Any more and I doubt it'll move at all. LOL

.....but thanks again guys!

 

well, i hate to say this because no one will believe me and it will just be a flame war but....


if you really want to get a t-5, i suggest getting a t-5 out of a v6 car. IT IS POSSIBLE TO USE IN A V8!!!! You will need a v6 clutch disc and a v8 pressure plate. this sounds nuts but ive done it 3 times with very good results. here are my reasons

1. junkyards will almost always cut a better deal on a v6 tranny
2. v6 t-5s are virtually identical to v8s in terms of gear stregnth
3. v6 t-5s have lower gear ratio in first and second gear but the same 5th OD
4. v6 t-5s live behind v6 motors, they are virgins to v8 power and usually in MUCH better shape

most people will disagree with me on this but ive done it and trust me, it works. i had a t-5 from a v8 living behind my 355 in my iroc, it turned itself into confetti after about 500mi. i stuck a v6 t-5 in there and it never happened again. and trust me, i beat the living snot out of that tranny!

no t-5 is bulletproof, but ive had better luck with the v6 ones

 

And with good reason, some might add.