Testarossa Gearbox fragility

I swapped my 91’s differential for Newman’s unit. I understand the quill shaft can break, but it can easily be replaced and its failure can likely save the gearbox.

I change the gear oil on a schedule using quality oil and ensure the shift linkage is well adjusted whenever I do an engine out service. After 60,000+ km it still shifts beautifully once warm and has never been rebuilt.

While never a good idea to abuse a clutch or gearbox in a heavy and powerful 30+ year old car, I am not convinced it is weak.

 

Hello Threeofnine,
I’ve also just replaced the differential and the quill shaft (which had already broken once and had been replaced with an original part) with components that should be more durable.
I systematically inspect the small 2nd gear pinion whenever I remove the engine-gearbox assembly to replace the timing belts. So far, it shows no signs of wear (the car is approaching 83,000 km).
I know of two Testarossas in which this pinion lost some teeth.
Sharing the same concern as you, I often shift directly from 1st to 3rd gear. I just rev the engine a bit more in 1st, and the engine has enough torque to handle it.

 

I had a Testarossa an early 85 modal with the single wheel hub nut during the late 90 s and ran it up for 30 K miles over 11 yrs of ownership.
I used the torque to drive it , never raced it and was sympathetic with it . Had 3 engine out belt changes in my tenure by a specialist and he did mention something about something going on the gearboxes , a “ weakness “ but then mentioned some were fine , others problematic ?
Mine was a ok one .
My conclusion is it’s a bit of a lottery which you have .
An experienced tech can tell with the gear change which is which .

It was the Ferrari classic first to third when cold . Which I obeyed btw .I suspect if those owners try and force it when cold , or don’t wait until it warm , start doing 1 to 2 too early baulking it , forcing it ….then they will bring on the issue that otherwise wouldn’t have happened .

Drive it sympathetically and it will reward you by behaving itself .

 

Whereas the 348's gearbox was notoriously weak (mine broke), I don't remember the testarossa's to be the same (mine did not break...).
I had each car only for a few years (although I had the testarossa longer) but that was enough for the 348, which was also more recent.

 

All above is okay when cold. I replaced diff with Newman. Changing gear oil, piece of tooth came out. Rebuilt gearbox with new 1st and 2nd gears. Was always noisy in 1st gear. 1st gear was spalled real bad and 2nd was just starting to show. Rest of gears perfect. The gearbox shifted and worked fine before. Now when I change gear oil, I use a paint filter to see if any foreign debris is in oil. No problems now and no noises. Rifledriver on here shows photos of bad 1st gears. I did a complete photo shoot on my gearbox rebuild on this forum. Look up my past forums. The quill shaft is the fuse link for the gearbox.

 

My BBi doesn't have as much power as a Testarossa, but I don't drive it nearly as delicately as being suggested here. If the car is cold, I might skip 2nd gear, but I certainly don't avoid downshifting.

Anecdotal story, a nearby neighbor has a Testarossa. I took him out in my BBi, and he about lost his mind. He said he had no idea these cars could be driven like that. Honestly, I wasn't thrashing on it. These cars aren't bullet proof, but they're much stronger and capable than people give them credit for.

 

I drive mine like it's a sports car. Until the car has warmed up a little bit (so oil off the minimum) I keep the revs to mid-range, but otherwise normal 1-2-3 shifts, etc. Frankly, I didn't buy the car so it would be a garage queen, I bought it to enjoy it. Getting out of highway tollbooths, I wring it out to the redline (and yeah, have fun doing a 1-2 shift while holding the window up button and checking mirrors as you're changing lanes).

I've not felt like the gearbox is a weak spot. As long as you rev-match, it'll slot into gear just fine.

 

Since the transmissions tend to break, several remanufactured versions (reputed to be stronger than the original parts) of all the necessary components are available.

https://www.hillengineering.co.uk/gearbox-parts
https://www.modenaengineering.com.au/
https://gtcp.com/product/second-gear-set-for-testarossa-512tr/

 

My 87 TR. I acquired the parts from GT parts in Arizona. The gears were made in Australia, probably from Modena Eng. Back then about $5,000 for 4 gears. 1st and 2nd complete. 1st gear is usually the first to show weakness. My 2nd gear was good, just showing signs of spalling, replaced it. The gearbox shifted fine before, just noisy in 1st gear. If I wouldn't have seen the piece of tooth, I didn't think anything was wrong. PO said, who he purchased the car from said they all are noisy! Wrong!! Always replace both gears on the set.

 

The propellor shaft passes though the rear cover, through an opening thats probably an inch and a half ID. The propellor shaft itself varies in diameter depending on the model but they're about 3/4" OD. I can tell if a car is driven hard by how defined the rub marks are on that shaft where it passes through the opening. The propellor shaft deflects that much under load that is contacts the pass-through and puts a wear mark on the shaft.

 

I'll bite, what is the "Newman diff" - internal gear set or outer cover or shafts or what exactly? It sounds like it a preventative in case you happen to have the bad luck of the draw on the diff/gearbox?

 

The original diff case has a welded end. They are known to fail and cause other damage. Not all are going to fail,( big debate about this). Newman sells a billet, fully machined case. Bolts in without to much effort, and takes original internals.