2.3L stroker with stock tranny

[scooby21043]

I have an automatic 1999 gst my mods are up to date in my profile. I was wondering since the next thing for me to do is build the motor if i need to upgrade my tranny or will the stock not have problems? I run 15psi dd and 22psi if im at the track. Now dont go on and say stroking a gst isnt worth it.

 

[thiazole]

The stock trans is fine - you just need something to increase the line pressure when you on the throttle to extend the life of your transmission.

 

[the_mork]

A few basic precautions should keep your transmission happy.

First is a new tranny cooler, you'll need something larger for spirited runs lasting more than a few seconds.

Second is a good fluid and filter. You will want an oem style replacement filter with the intake on the top as well as the bottom and a high quality fluid. Personally I like Diamond Star ATF but there are a number of other worthy fluids on the market so you should do a search to see what your best options are.

Third is valve body or computer modification for increased line pressure and firmer shifts. IPT has a shift kit which costs about $90 and will be helpful for any transmission but an alternative or compliment to this would be a remapped tcu from foreignmuscle.com.

Finally your end clutches will fail at some point. They are incredibly easy to replace and with shipping will come to just under $100 from IPT. The new end clutches will handle torque better but will still fail over time from brake boosting and hard abuse. Simply put the design of the transmission prevents an effective long term solutions for this problem but makes changing the clutches a half hour job. I suggest running each set to failure but keeping a set on hand, usually the first symptom will be a loss of overdrive that will still allow you to get the car home.

 

[dsm-onster]

AMEN! I wish 5speed trannies were that easy to mod and that cheap to keep going after abuse. Fvck the 5speed. . .

 

[the_mork]

Back when I was more newbish and before my car was modified I cursed my automatic because it wasn't "sporty" and people always made fun of it. These days I'm glad it is an automatic or else I would have changed my transmission many more times at significantly more expense. I also with I had known earlier how simple and inexpensive making these transmissions stronger was.

There is just one more thing that I didn't remember to mention earlier, and that is that you need something to protect your differential. Basically if you have significant wheel hop the diff can move in the case and either contact the case or break gears. There are two ways to solve the problem. The first is somewhat expensive (~$1000) and that is switching to an lsd such as a kaaz, quaife, or wavetrack which will also put power down equally to both front wheels (I forget whether you are awd or not and can't check while I'm responding). This is the best option but if you don't want to spend the money then there is a much less expensive option. The second option is to stiffen your motor mounts and suspension bushings. The motor mounts can be handled either by filling them with window weld for about $6 or polyurethane inserts. The suspension bushings can be replaced with kits from either energy suspension or prothane.

If you are awd you will probably break your center differential once you get to a lot of power on launches. One great thing about automatics is that they put less shock on all the differentials in the car as well as the rest of the driveline so even very similar parts in automatic cars will survive much more abuse.

 

[thiazole]

I've got about 12,000 miles on my car since I bought it in 2003, and I had just broken my second manual transmission before I made the switch to an auto. That is 1 transmission every 6000 miles. I obviously don't drive my car on the street that much - probably about 1000 street miles for every 1 trip to the track, but I still think the manual is just a money pit. The other big thing is that if you destroy a manual, you need to buy another built transmission or it won't last long. You can get a stock used auto for pretty cheap, and the work you need to do to it to get it to handle power is pretty cheap compared to the manual. Then, of course, there are the manual clutches. People talk about end clutches, but I've also spent about $1800 on clutches for my manual transmission during those 12,000 miles (although I admit that my last clutch was still good).

 

[blazinglaser_90]

As was said before a shift kit, get the tcu chipped for full line pressure at wot and a good filter are key. I swapped my 5 speed car over to an auto just this year went from doing a 11.4 @ 128 to a 10.4 @ 132 just b/c the car didn't miss a gear! I am ashamed to admit it but before I took my car to the track as an automatic.....I missed a gear every time I tried to race