prainma2006

I put a corvette servo in my 700r4 last night, I have a stock 305 tbi, no real mods. After I was done, I took it around the block, notice it doesn't want to shift until 4000 to 4500 rpm, stepped into the gas from a stop and went to red line, didn't shift to second until I let off the gas around 5500 rpm. My question is I didn't use anything when I put the servo in, ie grease or tranny fluid, could it maybe be sticking in there or should I have used something for lubrication? I haven't driven more than a test drive, 3 or 4 miles, 2-3, and 3-4 seem to shift fine. 1-2 shift feels firm when it shifts, just shifts in weird rpms, and not when I think it should. Ant advice would be greatly appreciated. Car has 134000 mi, original trans, 1-2 was getting a little soft so I was trying to firm up 1-2, maybe it is just time for a new trans. Thanks

customblackbird

iTrader: (15)

when i took out my corvette servo to put in the biggest billet servos they make for the 700r4 i was told in the instructions to coat everything in tranny fluid. also there is something about adjusting a "pin" that it sits on if needed. u should have soaked it in a can of tranny fluid and stuck it in. u dont want the seals all dry

ed o

the corvette servo likes to stick the inner(where the red o ring goes) in the bore. it causes grief to install even on a workbench sometimes. What happens is it ***** sideways a little. To install the stock servo it never seems to stick like the corvette one so the whole assembly can be installed together. to install the corvette you need to do it differently. Push the servo in while leaving the cover off while trying to get the inner with the red o ring straight. Then install the fourth piston and cover.
If you have the money I'd install the jet servo(T.c.i. sells the same one) as it installs way easier and makes the shifts better IMO. It's even easier than you think with the jet servo(not the corvette type)-----it's a no brainer!!!!!!!

customblackbird

iTrader: (15)

most ppl who build transmissions are against the whole SUPER LARGE billet servos. untill they are needed. i had a 30min convo with DANA from probuilt automatics who is very respected on this board. and he really knows transmissions. he states that the corvette servo is more than adequate for stock to higher perforamance transmissions up untill about 600-650hp. he states that the billets have wayy more clamping power and can cause shock to the drivetrain being that they engage and clamp so hard. also known as that BUMP shift at lower RPMS. they can also cause drivabiltiy problems when releasing the servos bc they are so large. his higher HP kits also only use the smaller billet servos like 14% larger than corvette servo. and they hold up to 8s trans no prob.

i believe him but i already installed mine 40% LARGER than corvette billet servo, and 50% larger than stock 4th gear servo. along with the largest boost valves etc and i love it. shifts really hard and that lil bump shift from 1-2 even at 2000 is enough to make ur head bob hard... just lets ppl kno not to mess wit me

in other words u dont need the billet servos. the corrvette is more than find for your application. do it again, follow the instructions and make sure u dip that thing in new trans fluid before it goes in. make sure the seals are nice and wet too.

ed o

the car is a 305. The billet servo v.s. corvette isn't going to "break" anything at that level. I like the billet jet because the spring inside the servo is eliminated making for a better third gear also (it is a dampener spring for third accumulation). I feel the overkill part, but for this application why not go for a little firmer third gear at the same time? BTW the 92 rs probably already had a vette style servo in it. Was the last three digits 093? If so you replaced the servo with the same thing.

customblackbird

iTrader: (15)

yea i was just saying incase he thought about leaving the trans behind a stongermotor. even on my lightly modded 350tpi. stock long block just ported intake and exhaust and it kicked real hard with the billet servos.

i also believe the newer 90-92 700r4s had the larger vette servos.

ed o

which servo's did you use? I'm always curious about shift quality with different products.
did you use a fourth gear piston and cover also?

customblackbird

iTrader: (15)

i used supeior's billet servos. i got it as a kit from raptor transmissions. its a 35 0r 40 percent increase over the stock vette servo and the 4th gear servo is a 50% larger than stock and has the matching billet cover.

i upgraded to the larger servos and boost vavles over my recently built upgraded 700r4 that had the corvette servo and transgo shift kit. the billet servos and boost valves made a nite and day difference. i love it. its pretty harsh vs the vette servo but my 3-4 shift is alil on the BLAH side compared to the insane neck snap/firm shift of the 1-2 shift. the 2-3 shift is quick and nice until i get higher in the RPM ranges like above 3500 then its pretty firm lol. felt like riding a stick at the track.

ed o

yeah. I was wondering about the 3 to 4 shift mostly. apparently the billet piston and servo cover didn't do that much in your case. I know blocking the fourth accumulator completely with the transgo 2-3kit installing a plug under the 4th accumulator piston doesn't make fourth unbearable either. I normally just flip the spring and piston for 4th accumulator like in the JR transgo kit instructions as I hate modifying transmissionn cases. I wonder if blocking with the plug, and using a aftermarket piston and cover makes it firmer. anyone? anyhow thanks bird man.
BTW-what happened? replace the trans or what prainma2006?