ok guys i have a 91 z28 automatic.. ive been having alot of problems with my tranny for a while the tv cable keeps messing and and now that i replaced it according to the machanic the valvebody needs to be replaced. ive heard that the 700r4 trannys are no good so which brings me to this question. wat do u guys think i should do? swap to a t/56 or another auto tranny or rebuild the 700r4 again! it be nice to have a six speed but idnt no wat to do!

 

A good, rebuilt 700R4 with upgrades would be the easiest, unless you really want a manual.

 

th350 and 400s are great trannys and they are plentiful.t56 is good but its gonna cost you more money to put it in.

 

well i from alot of people that they have problems with that tranny. so then i heard that its better to just get a manual

 

wats the difference between the th350 and th400 and how well do they perform as in daily driving and racing

 

if your gonna go with the manual make sure you find a good doner car so you can get all the components you need to swap it over

 

the 400 is a little stonger and has better gear ratios for the strip but both are fine on the street.

 

TH350s and TH400s are great, and relatively cheap to build up, but over time the loss of overdrive will eat up the cost difference at the pump. The 700R4 had a bad reputation when it came out, because it was a new product, GM hadn't got the bugs out, and nobody understood how to build it up yet. That was 22 years ago though.

 

yah thats the only real drawback

 

is the th350 and th400 just bolt on? or do i have to buy xmembers and all those things like for the t/56

 

They don't bolt in as easily as the 700R4 that the car was designed for. Depending on whether you get a long or short tail transmission, you could need things like crossmembers and driveshafts. Either way, you'll need something to mount the torque arm, too.

 

o ok. im a newbie to transmissions so im in the process of learning. do u all think it would be better just to rebuild me 700r4 with high performance parts

 

I do, but opinions may vary.

 

i think you could make the stock crossmember work as long as you get one with the short tailshaft i believe its only about 1/8" shorter than the 700r4. but apeiron is right you will need some way of bolting the torque arm to it.

 

i think that would be the easiest route since nothing is changing except the insides. that way you wont have any issues bolting it back in. that would be my choice.

 

IF it was me, i would stay with the 700r. they cost a little more to build if you do it right with the correct upgrades for your application they are VERY reliable. But the extra cost is nothing when you factor in long term. the gear ratios in the 700 are much better off the line and you still have o.d. .. I build these cars for a living and you could not pay me to put a 350 or 400 turbo in a street driven car. those trans in my opinion are for cars that are track only and geared for such... In all reality the same car, eng. and rear gear the 700r car will prevail every time. I'd need to know more about what exactly your doing with it to be able to give any advice on your needed upgrades. of course a vette servo, but thats only the tip of the iceberg. the Transgo sk700 jr kit is one of the most common upgrades i do, but again thats all in what your doing with your Z.!!.

 

Id also get a 700r4. U can get a nice one on ebay for under $1000 that includes a tq converter of your choice, shift kit, and shipping. Also it would pretty much handle up to around 500-600 hp.

 

well for now being that its the only car i have i usually daily drive it to school and things like that. i like to race but right now theres no way i can cuz they closed the local track but when someone wants to race on the street i go for it so its like in between of daily and a "race" car but i daily it more lol i want it to be a good cruiser but when i push it i want the respond of a quick car haha

 

well just my .02 i hate my 700r as soon as u put power to them they dont hold.maybe just my luck but im switching to th350 for sure. all u need to swap over is the umi crossmember that also relocates the torque arm.but u need the th350 with a 9in tailshaft also and u can use the stock 700r driveshaft. and the th350 may not have od but the first gear isnt as low as the 700 so with the right rear gearing and rear tire will not be horrible on the street unless u plan on highway cruisein.