A couple of sites in the USA, one about converting them into Jag's & they fit the billet retainer amongst other mods to make them hold the power.

sd1800 -> you may only need a billet retainer if the rest of the box is in good shape.

Cheers

ToranaGuy

In 12 months of Saloon car racing I broke 3rd gear in 4 gearboxes. They are weak and a major problem as a standard box.

There is a solution which most saloon car drivers have for there AU's as they have to run the EA box in them and most AU's are pushing just over 200 Kw's at the flywheel but its an expensive solution.

They use a Pizfizer (Not sure how to spell it correctly) gear set which in a road car would never break but the gear set alone is worth about $5,000.

Ouch! That's expensive. Who rebuild & toughened up boxes from the US are less than that, from what i've found.

Cheers

ToranaGuy

The issue with the T5 is that as the gearbox heats up the aluminium casing expands at a faster rate than the steel gears it contains. When the gearbox is assembled, a certain amount of pre-load is placed on the gear assembly on the mainshaft. The preload is set by shimming the thrust bearing at the front of the box. This preload helps keep the gears aligned and in position. As the gearbox heats up with use, the preload is reduced, thus making things inside a bit sloppy and a lot more prone to breakage. This is one of the main reasons Ford originally introduced a significantly reduced towing capacity for manual cars. They keep it now as it significantly reduces warranty claims related to clutches etc.

The way around the problem is to maintain preload. You need to do this in three ways:
1. have the gearbox assembled in the first place with the preload right at the tight end of spec.
2. using the right lubrication fluid (which is automatic transmission fluid - gear oil will kill the synchros and make it a pig to shift - Castrol Transmax Z is the best stuff)
3. Run a cooler on the box. We did this on the cheap with a Holley red fuel pump (don't use a carter - they are a better fuel pump, but as they have a wet armature, they won't spin with the more viscous ATF in them - Holleys are a dry armature arrangement and work fine, and you can now also get special oil pumps aftermarket which would be even better)and a aftermarket auto transmission cooler mounted up the front. Drill and tap holes in the side of the main casing (one near the bottom to collect the fluid) for 1/2" BSP fittings, connect up some lines and away you go. We ran a temp gauge on the gearbox and the cooler made about 30 deg difference when worked hard.

That makes sense about the preloads as the Pizfizer gear sets have straight cut gears which would eliminate the pre load issue.

Also I forgot to tell how good these gear sets sound. They have a whining noise like having timing gears and they sound really tough

slacker -> Thanks for a very informative post man. I figured the alloy casing expanded or twisted from either torque or heat after a while, causing the shaft to get sloppy inside & cause issues, but that adds more science to the issue.

ATF? Interesting. I can't remember what fluid i used, but it was recommended for ford 5 speeds. I have to change the clutch soon, so i think i'll try some ATF in it. What grade should i use. Dexron 3? 95LE?

Running a cooler on the box sounds like a great idea, i might be selling this car, but if i keep my Xr8 which has a 5speed in it, i'll look into adding a cooler.

Neilo77 -> I bet it does sound good, but i doubt it's street friendly......

Cheers

ToranaGuy

I've also got a straight-cut close ratio T5 (I think the PPG a*** are the standard ratio set) from another mob: 2.2 first and 0.88 fifth. It's quieter than the PPG gears, but still really loud. Sounds great for the for half an hour or so and grates after that! We have worn earmuffs in the car.....

Use Castrol Transmax -Z. It's synthetic and about as good as you'll get.

I have a T5Z out of an AU Xr8 in my car, they use straight cut gears and is noisy as hell, can hear the thing whining away all the time, when i floor it, almost sounds like I'm running boost , just freshly rebuilt it, and filled it with Transmax Z, pretty thin stuff, almost like water! But it's good for the box as the T5 has very small oil feed holes.

The billet bearing retainer is a good idea too as you can get correct preload for the bearing, as the factory stamped one flexes under load, and won't give you correct readings when trying to set it either. When setting preload, at first you will be like "holy s**t, this can't be right, it's way too tight!" but then you realize why it has to be.

For all those interested in the retainer, i got mine from John Cerini, from Cerini Motorsports in the US, great bloke, helped me a lot with my rebuild and sent me all the parts i needed plus some, he's built boxes for NASCAR and all sorts of other places. http://cgi.ebay.com/ebaymotors/T5-Bille ... 27af0c5d01

All ford V8 T5's should be using ATF, Transmax Z is the premium goods! I had to hunt it down for a very long time as they don't sell it here in bottles like they do in Aussie. Straight cut gears are pretty street friendly, and they do sound awesome, can hear them very well inside the car, with the window down, i can here the box whining away like a blower, even over the exhaust note, sounds very cool, and i'm only using the factory T5Z gears, some people go for those after market thicker ones which will be even louder, they must start to get pretty annoying if driving around for a while lol.

Fair enough man. I will use ATF when i refit the box after i change the clutch, which i must do real soon. I keep telling myself that, and other things keep getting in the way of getting it done. It doesn't slip badly when driving the car without a trailer on the back, but load up a trailer, with a couple hundred kg or more & bring on the slip lol.

I checked out the link for the retainers, that's pretty cheap to keep the boxes from blowing up the way they do. If i have to remove either of the Xr8's T5's, i will be fitting a billet retainer before the box goes back in, as insurance.

Cheers

ToranaGuy

a lot of great info here, really answers a lot of my questions, now im wandering if i need to get a cooler on my t5 when i run more power and if i need to get the retainer aswel... actually didnt know that the t56 is a stronger box... thought it was basically a t5 but with one more gear...

but i definately wont go to autos, just too boring no fun...

i guess i wont give it much in 3rd gear then, soo all gears but 3rd are pretty strong?

and if i do end up getting a straight cut down the track will that be too expensive? like compared to a rebuilt t5? and is a rebuilt t5 bascially all new internals or just 2nd handies?

Build it your self mate. I'm not sure how much after market gear sets cost, but the Tremec Z gears cost me: $240- cluster, $85 second gear and the other gears were about 60-90 each. US dollars, Z gears are rated to 330 ft lb of torque.

You can get heaps of heavier duty versions too, but obviously cost a lot more.

They are quite easy to build too! I was very surprised with how easy they are.

ahh ill have to look into doing that then, how much torque can the standard gears take compared to the z gears? are they like much stronger or? becuz by the end of my build i wana have around 400kw atw

Get a T56.

just get a T56.

I love how everyone thinks this billet retainer will eliminate case flex. The a*** is not the problem, the case flexes, separating 3rd gear. That is when it strips 3rd.