Depends on condition, how you drive, what clutch you are using, how many miles it has already, to many factors for that vague of a question. I would say a 1g transmission will probably need a rebuild at the least to handle that kinda power to the wheels.

It's hard to set a hp mark for a transmission. Every transmission is used differently, some take more abuse then others. So to say a transmission can hold a certain amount of hp is just a guess and varies for each one.

I've seen 2g awd dsms put down 400 at the wheels on a stock transmission.

the tranny is in good condition doesnt grind any gears. act 2900lb clutch with a 6 puck. with the 16g it made 315hp no problem but how long with it last with the new 30r setup

Are you an aggressive driver?

400 hp to the wheels. Wow that quite a bit there.. Hmm... Well if thats true than that will make my list of things to buy shorter

Evil Eagle ran tens on a stock transmission and I think nines. But I have seen stock transmissions go with around 300 whp. Depends on a lot of factors not just power.

awd92lesky said:

the tranny is in good condition doesnt grind any gears. act 2900lb clutch with a 6 puck. with the 16g it made 315hp no problem but how long with it last with the new 30r setup

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Unfortuneately, no one can neccessarily tell you how long that tranny will last, only how long it could last. Rather than push the tranny to it's limits or beyond and find out the hard way when it will break, you could begin saving cash or go ahead and buy the upgraded tranny. With only 315hp, you should not need anything crazy, I would think that the Shep level II tranny would be a good tranny for you. BUT if you plan to turn up the power, then you should look into that level 3 or 4 tranny uprgrade that Shep offers. If you are really tight on money, I would suggest you concentrate on being as nice as you can to the tranny you currently have. Put some good gear lube in it, change it often, and drive it like it is going to break tomorrow.

I also believe the fact if its AWD or FWD plays a huge roll in the hp it can handle.

Holy thread revival Batman!

I ran a 13.03 @108 last season on a stock awd trans that the third synchro was going out of..
I remember reverse popping out when I was leaving the strip...

ive Heard 400 whp

I got a 2g auto tranny. I've heard that it can handle 300whp.

^^stock auto's can hold WAYY more than 300whp. With a shift box and IPT end clutch kit it will easily hold 450whp

Maroon4g said:

I also believe the fact if its AWD or FWD plays a huge roll in the hp it can handle.

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In a FWD you end up spinning tires which is a lot easier on the trans than the shock load you get from the hookup in AWD.

This applies to pretty much all drive train components in an AWD vs FWD.

bench racer thread, theres no answer to this question.

To answer this question for anybody who is looking for it:


Depends how you drive it, Only you will find the limit of your transmission!!!

I still have my 24yr old stock tranny with 195K miles on it and no bad syncros. Loaded with MT-90 and shifts smooth.

Course, I don't beat it to death, behave and do DD freeway driving .. if that is worth three cents of information ....

True though - a bench racing question being no definite answer.

Only closee answer is the one who really wants to keep adding huge amounts of HP to see which HP number is needed to blow it up (and hope nobody is around when it does let go, for the driver will suddenly lose control of that said vehicle) .. and the results is still not the definite answer.

My old transmission in my '92 AWD held 315 without any further problems than a 2nd gear grind (which would go away after letting everything warm up and doing the 1-3 shift for the first 15mins of driving). I beat on it almost daily and launched it around a dozen times with 150k on it. I guess I just got lucky. As mentioned above, it really depends on a lot of factors.

I think torque is a bigger factor than horsepower when discussing the limits of a trans.

At 600 whp they seem to last about 100 passes. At less than 400whp, the gears should last almost indefinitely, barring other problems. At 800whp, it's probably in the area of 10 passes.

Horsepower in fine for talking about gear life. Any horsepower level is going to have a fairly narrow range of torque it will produce.

i have 800 whp whit almost stock gearbox with welded center diff,double Synchronous, and modified front diff bearings, she holds quite well . i have twin disc 7.25 and act FCV shift at 10000rpm

I'm positive it has more to do with torque and what rpm you shift at than hp.

Twinturbo120 said:

I'm positive it has more to do with torque and what rpm you shift at than hp.

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Torque and RPM the two variables needed to calculate horsepower.

Horsepower = Torque X RPM / 5252

Twinturbo120 said:

I'm positive it has more to do with torque and what rpm you shift at than hp.

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I'm also positive, that you have no clue what your talking about, nor have you any level of expertise on the design of gears. Nor have you ever made enough power to hurt a dsm transmission.

The failures that you will see are endurance limit failures. The harder you load a tooth the less times it will take it before a crack forms and it fails. So, more power means either more torque (higher loading) or higher RPM (more cycles).