Looks like mine's going out. Guy has a rebuilt one on craigslist. Need to be able to make sure it's the right one.

 

If it has a tag on it and it hasn't been swapped check the numbers here.
http://www.britishv8.org/articles/bo...t5-id-tags.htm

If there is no tag put it in 1st and count how many turns on the input it takes to spin the output shaft one revolution. V8's were 2.95 1st gear.
Check to make sure it has the chevy bellhousing pattern.

 

Thanks so much for the help. I really appreciate your taking the time.

What is it about the countershaft bearing design that tells you it's a World Class T5?

 

You've been provided a link with the information.

 

To me, those look like freeze plugs. I don't see where they're marked "Timken", or have a part number on them.

 

I see them on the picture in this thread.

 

1st and 2nd (wc) design T5.

 

6-cyl trans has a 1" dia 14-spline clutch; V8 has 1-1/8" dia 26-spline.

 

If it has the 4-bolt pattern like these, and it has a 26 spline input shaft the exact same length as yours including the pilot tip end then it's a V8 T5.

If it has the other bolt pattern, or another spline input, or a 26 spline input that's longer, it's not a GM V8 T5.

 

I recall reading where there were two different gearsets available in GM WC T5s.

Here's what I've found:

1988-92 V8 M39, world class Input shaft, 24T, 26 Spline, 8.75” Long.................................................. 1352-085-019
Cluster, 31-29-22-15-14 (1352-077-053).................................................. 1352077070R
1st gear, 32T (2.95 ratio) (1352-080-034)................................................. 1352-080-031
2nd gear, 33T (1.94 ratio).......................................................................... 1352-080-028
3rd gear, 30T (1.34 ratio) (1352-080-045)................................................. 1352-083-002
5th Mainshaft gear, 25T (0.63 ratio)......................................................... 1352-070-023
5th Countershaft gear, 51T (0.63 ratio) (1352-080-035) ......................... 1352-080-051


1988-92 V8 MK6, world class Input shaft, 24T, 26 Spline, 8.75” Long.................................................. 1352-085-019
Cluster, 31-29-22-15-14 (1352-077-053).................................................. 1352077070R
1st gear, 32T (2.95 ratio) (1352-080-034)................................................. 1352-080-031
2nd gear, 33T (1.94 ratio).......................................................................... 1352-080-028
3rd gear, 30T (1.34 ratio) (1352-080-045)................................................. 1352-083-002
5th Mainshaft gear, 31T (0.73 ratio) (1352-070-043)............................... 1352-070-047
5th Countershaft gear, 55T (0.73 ratio) ................................................... 1352-080-052

Is this correct?

If so, how do I determine which I have, and what I'm replacing mine with is?

Thanks

 

Put it in 5th gear. Turn the clutch gear EXACTLY one turn. Count how many times the mainshaft turns.

If it turns 0.73 times, you have the good performance version. If it only turns 0.63 times, you have the crappy TBI/LG4 version, that always feels like it needs a 4½th gear. Yeah I accidentally put one of those POSs in my T-5 once by mistake... I actually pulled the trans back out after acoupla weeks and put the right 5th back in it, because the grocery-cart 0.63 made it so obnoxious to drive in rush-hour freeway traffic.

 

Mine's a TBI car.

Maybe it's because of the 3.42 gears I swapped in, but I don't notice drivability problems like that in my car.

When I'm driving on my commute, I tend to short shift it. I'm usually in 5th by 40mph, and it pulls.

 

That's because you don't know any better yet.

Go drive a car with the performance gear. Especially with a motor that makes meaningful power above 3000 RPM. You'll discover why the one is the performance one and the other is just the .... TBI ... one.

My gears are just the lame weenie stock ones; 3.73. But since I put a T-56 in the car I've been wishing for more. I can't begin to imagine how crippled yours must be with what you've got.

 

Look, I've had cars with huge drops between gears; especially 5 speeds with overdrives going into 5th. Mine doesn't feel that way; certainly not "crippled", as you describe it.

The only problem I have with my 5th gear has nothing to do with my Firebird at all. My daily driver is a Jeep Cherokee. In the Jeep, 60-65 mph means around 22-2300 rpm.

My Firebird doesn't have cruise control. On the highway, I subconsciously find that 22-2300 rpm cruising range I run at all the time in the Jeep. The problem is, in my Firebird, with 255/50 16 rear tires, and 3.42 gears, 22-2300 rpm means 80 mph.

That's what makes the .74 overdrive attractive to me.

So, where do I get that gear? It's looking like we're going to have my T5 rebuilt. The guy who is going to do it says he has no source for that gear.