Ford Mustang Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
1,501 Posts
Discussion Starter #1
I am converting my 347 68 Cougar to a 5speed and chose the T5Z due to ease, trans tunnel mods, weight and a bunch of other little reasons.
My question is what breaks the T5Z. Is it always 3rd gear, if I don't dump the clutch at 4k will it live? Is it when the car hooks that they break?
What has been your experience?
I had one previously in my 83 gt and in my 64 falcon, no problems running mid to low 11's in both cars....but this car is heavier and has way more power
(347, 11R heads, 10.75 compression, FTI custom cam for this build (6500 redline)
Vehicle weight 2820
3.80 gear 28" tall tire (radial)

-Mav
 

·
Registered
Joined
·
155 Posts
In my old drag car I blew 3rd gear apart twice running mid 11s at 2820#. These were just stock used units I was finding locally and trowing in the car. No clue on miles or anything before I put them in. They were cheap and plentiful in the early 2000s.
 

·
Registered
Joined
·
511 Posts
If a car on drag tires. The mainshaft on launch. New mainshaft and tailhousing to repair. Down track, 3rd gear. New 3rd and countershaft to repair. After many accumulated runs the main case between the 2 aft bearing bores have a tendency to crack between bores. New case, counter shaft and whatever gear it was in at failure. Minimums for repair.I had better luck with older Borg-Warners T-5's than the newer Tremecs made in Mexico. Slip at the tire or the clutch is always a good thing. ET or longevity.
 

·
Registered
Joined
·
1,027 Posts
Did you buy a t5 z spec new?

You can get an Astro a5 or promotion worked-over t5 for almost the same price...

Some people are able to run big power behind a z spec, some aren’t so lucky.

Astro, promotion, or g force are the only way to go for higher hp builds imo.

I run an a5, it’s a stout trans and shifts like a stock t5.
 

·
Registered
Joined
·
1,501 Posts
Discussion Starter #5
yes

Did you buy a t5 z spec new?

You can get an Astro a5 or promotion worked-over t5 for almost the same price...

Some people are able to run big power behind a z spec, some aren’t so lucky.

Astro, promotion, or g force are the only way to go for higher hp builds imo.

I run an a5, it’s a stout trans and shifts like a stock t5.
Yes I ordered it today from Modern Driveline. It was way cheaper than the astro and gforce that I saw.
From Modern it was $1895 free shipping and tax free through christmas. So I ordered it.
 

·
Registered
Joined
·
1,027 Posts
Ok gotcha. Pro motion are probably the cheapest I’ve seen with built t5s. They start at around $2100 for a 500-600 horse unit. When I talked to Walt he mentioned that was whp, which I thought was interesting.

http://promotionpowertrain.com/TRANSMISSIONS_.html
 

·
Registered
Joined
·
915 Posts
In my experience with T5s and T5z specs, 3rd has been the issue. I didn't have many issues with stock or stock like clutches and power. Add in an aggressive aftermarket clutch, sticky tires, more power and especially a powershift or two and you have a recipe for failure.
 
1 - 7 of 7 Posts
Top