Transmission Carnage Thread

[Hawk77FT]

Originally Posted by VeloxEric

Can't agree more with this information. I'm glad you guys got a hold of the proper people... I was going to say 10-15% improvement in strength optimistically.

One guy testing the unit local to me, after we test the gearset for a few thousand miles, wants to do REM ISF and Cryo for peace of mind. We will hopefully have some idea how much reduction in drag REM ISF adds as we are going to do back to back dyno .



If (when) it breaks, please take pictures!!!

We do have a spare gearset if you're interested in trying it out. The person who initially wanted to try it out backed out I think, can't get a hold of him.

How much to get a spare gearset is these days?

Originally Posted by FRS Justin

I am interested in that very interested, I will call you

Sent from my HTC_0P6B using Tapatalk

[FRS Justin]

With TX2K a little over a month away I'm prepping the trailer with common parts ect just in case.
Question has anyone ever broken 1st or 2nd gear in a manual trans. I plan to be leaving the line under 15 psi of boost and am starting to wonder what to expect from this trans with slicks on the rear... Should I put 1 or 2 extra trans in the trailer for this weekend of fun.. Your thoughts please, and thank you


P.S. I never heard of a 1st or 2nd gear failure so if you have had one please let me know... thanks again

[Dream20b]

Sub'd.

[CSG Mike]

Under what kind of conditions are you shearing gears?

Obviously, with enough torque, you can straight up shear the gears at any temperature and condition (assuming the tires hook up), but we've not yet determined the "middle ground" where the transmission will fail if it gets hot, but will be okay if it stays cool.

Is this at the track where the transmission is getting really hot, or on the street/dyno? Have you guys used a transmission cooler, or observed transmission temperatures when the failures occured?

[churchx]

Hmm, interesting. Indeed, who knows if it's just mechanical design weakness or in combination of overheating. As for 4th gear being narrower/thinner, it seems logical to me in design, as originally it was not meant for boosted engine, and there should be less torque then in lower gears, hence engineers may had been just up to choice of over-engineering and making much wider/stronger (with possibly increasing mechanical power loss) or adding just enough.

[crazyfrenchbiker]

Originally Posted by FRS Justin

With TX2K a little over a month away I'm prepping the trailer with common parts ect just in case.
Question has anyone ever broken 1st or 2nd gear in a manual trans. I plan to be leaving the line under 15 psi of boost and am starting to wonder what to expect from this trans with slicks on the rear... Should I put 1 or 2 extra trans in the trailer for this weekend of fun.. Your thoughts please, and thank you


P.S. I never heard of a 1st or 2nd gear failure so if you have had one please let me know... thanks again

@mrk1 Can point you to a guy who has similar power and launches at 6-7K off the line.

I believe most of the stress from a launch like that will be on the clutch.

[justatroll]

Here's one posted by @Dipstik-sportech



One of the guys I race against in vintage swears by trans coolers. He said he had been through 5 trannys before he put a cooler on and needs to rebuild them far less frequently now.
Different car of course, but very similar trans internals.

I wish that stock tranny designers would incorporate some internals that would double as the fluid pump if you just open two ports.

[VerusEric]

Originally Posted by Hawk77FT

How much to get a spare gearset is these days?

Transmission? ~$400-$1000 from what I've seen. Our gearset is significantly more but with increased strength comes an increase in material, labor, and time.

Originally Posted by FRS Justin

P.S. I never heard of a 1st or 2nd gear failure so if you have had one please let me know... thanks again

Only the one case in the initial post. Severe wheel hop in 2nd at 500rwhp, he admitted driver's fault. That kind of loading/unloading is hell on mechanical parts.

Originally Posted by churchx

Hmm, interesting. Indeed, who knows if it's just mechanical design weakness or in combination of overheating. As for 4th gear being narrower/thinner, it seems logical to me in design, as originally it was not meant for boosted engine, and there should be less torque then in lower gears, hence engineers may had been just up to choice of over-engineering and making much wider/stronger (with possibly increasing mechanical power loss) or adding just enough.

3rd and 4th is generally thinner due to the overall design of the gearbox, which is typical from the handful of different transmissions I've torn apart. Between 3rd and 4th gear, the shift sleeve/clutch needs to fit. Due to the size of the gears and the close proximity of the other shaft, it leaves less room for gear material. Granted, this is just a guess, no one can hint at knowing what Toyobaru was thinking when designing the gearset.

It's unlikely a heat issue as some of these are killed on the street less than half an hour into a drive, others on the track. Most steel holds up well to heat and a little ductility would actually help in this case. The stock gears are extremely hard, but extremely brittle. This is great for a long life at stock power, but ultimately the demise for higher horsepower and abuse that comes with increased loads. You actually want a bit of give so that the gears don't just shear off and they can absorb the loads.

Originally Posted by justatroll

Here's one posted by @Dipstik-sportech



One of the guys I race against in vintage swears by trans coolers. He said he had been through 5 trannys before he put a cooler on and needs to rebuild them far less frequently now.
Different car of course, but very similar trans internals.

I wish that stock tranny designers would incorporate some internals that would double as the fluid pump if you just open two ports.

Thank you sir! Looks like another unit that did not ruin 4th gear retaining clip but killed the gear itself.

I have spoken with Phil at Element Tuning and he has ran a cooler. He said it ultimately helped a bit but he still killed transmission after transmission. Personally, I see a trans cooler potentially helping shifting engagement, but as far as gear strength, I don't see it yet. Granted, I do not claim to know everything. Thank you very much for the submission!

[churchx]

If one redesigns for strength gears and for their installation gearbox needs to be cracked open anyway, imho it's worth to get two birds with one stone and during design process incorporate also different ratios, eg. like in close ratio gear sets ..

[Speeeddemon99]

Hello all. Quick post. I have a 2014 FR-S monogram. I recently had my last free service of 60,000 miles. Currently have about 59,976 miles on her. I complained about a whine on my transmission when my clutch isn't engage, loose TRD short throw shifter, etc. So long story short...... Throw out bearing is shot. 1st,2nd,3rd,4th gears are bad! And another issue with gearing. And the TRD short throw screw was backed off about 2 turns. My car is completely bone stock! Other than TRD accessories ( air intake, sway bars, short throw, lowering springs, exhaust, and TRD 18" rims with Michelin pilot super sport ) they said my clutch was in good shape! But I went ahead and ordered TRD clutch since it's all broken down. Is this wear normal? And another side question...... Should I get aluminum drive shaft? Or keep it stock. Thanks in advance

[Calum]

Originally Posted by Speeeddemon99

Hello all. Quick post. I have a 2014 FR-S monogram. I recently had my last free service of 60,000 miles. Currently have about 59,976 miles on her. I complained about a whine on my transmission when my clutch isn't engage, loose TRD short throw shifter, etc. So long story short...... Throw out bearing is shot. 1st,2nd,3rd,4th gears are bad! And another issue with gearing. And the TRD short throw screw was backed off about 2 turns. My car is completely bone stock! Other than TRD accessories ( air intake, sway bars, short throw, lowering springs, exhaust, and TRD 18" rims with Michelin pilot super sport ) they said my clutch was in good shape! But I went ahead and ordered TRD clutch since it's all broken down. Is this wear normal? And another side question...... Should I get aluminum drive shaft? Or keep it stock. Thanks in advance

Make a separate post.

[FRS Justin]

Originally Posted by Calum

Make a separate post.

Do you have pics of the bad gears? How did you drive this car mostly? Did you change trans fluid or run stock? Any info is appreciated

[Speeeddemon99]

Originally Posted by FRS Justin

Do you have pics of the bad gears? How did you drive this car mostly? Did you change trans fluid or run stock? Any info is appreciated

Actually yes I have a few pictures of the gears that the tech at Toyota was kind enough to text to me. I'll try to get them posted

[FRS Justin]

Originally Posted by Speeeddemon99

Actually yes I have a few pictures of the gears that the tech at Toyota was kind enough to text to me. I'll try to get them posted

Awesome thanks