flyin89

iTrader: (7)

I have rebuilt a 700r4 (my 3rd) .500 boost, .296 reverse boost,vette servo,trans go 2&3 kit and a hardened sunshell. All specs are where they belong. The transmission works fine in all gears but 3rd (D). 1-2 shift is nice and crisp 2-3 shift binds and feels like I suddenly had a 10k lb trailer hooked to it. It will stay binden as long as its in 3rd. 3-4 shift frees up and feels great. reverse is great.

It seems like either somehow the band is re-engaging or not releasing on the 2-3 shift. Any ideas of area I might want to check. Valvebody problem? Improperly drilled holes?

I'm hoping one of you guys can point me in the right direction.

ed o

bindups are normally a sprag in backwards or a crossleak at a sealing ring (the sized ones). sorry for the bad info. doesn't sound promising with the trans in the car already.

if the trans binds-the valve body is probably doing its job because it commanded the gear to be applied but something isn't allowing the trans to do what the valve body asks. make sense? the valve body is the messenger. if it makes the shift happen (binds up).

the band is releasing because you are getting a 1-2 up and down shift.

the checkballs might actually be the issue. depending on year they go in different positions. the JR transgo shift kit explains it a little better than the 2-3kit, and the transgo separator plate 700-p instructions make life even easier. If I were you i'd borrow or buy both of them. it will help clear things up.

follow the 700-p instructions first, then use the other instructions (preferrably the JR). in that order!!!!
BTW/ nice ET and mile an hour. impressive....

flyin89

iTrader: (7)

1) The sprags are new and I checked both so I'm sure they aren't the problem. I'm doubting its a crossleak however I would rather rulle out other possibilties before taking the trans out.

2) I agree 100%, the trans works perfectly except 3rd gear all gears are firm its definitely a valvebody or circuit problem.

3) However that won't mean that the band will be pushed away on the 3rd gear shift does it? I have been wondering about the capsule in that circuit on the way to the servo. Is there a way to airtest it? The capsule checked out okay with the trans bare and upside down. I have a brand new 700P plate. However I won't have the plugs that I had to put in the spacer plate.

The trans is a 1993 which has a few oddities that I have noticed.

Thanks for the help and hope you can further relate on this.

327_TPI_77_Maro

iTrader: (8)

Did you ever get this fixed? Curious to hear what the issue was.

Bjoern

I have the same problem, any advices? Nearly the same specs, .500 boost valve, .296 reverse boost, alto red eagle frictions with kolene steels, hardened sun shell, Borg Warner sprags, TCI super servo....
My alto high performance kit came with a freeze plug for the 3rd accumulator which I installed, might this be the problem??
Help would be awesome, don't want to tear the whole tranny apart!
Thanks in advance guys!!

ed o

Most likely your tci servo not releasing the band. The plug needs installed with vb off at bottom of bore. Take a pry bar and make sure you can push the cover for servo in a ways indicating it will release for third

Bjoern

Hi Ed O, thanks for your fast reply! I already installed the plug when I did the rebuilding. With leaver in OD it shifts all four gears without any problems only when it is in D!

All the best
Bjoern

RBob

iTrader: (1)

It may be an issue with the overrun clutches. With the shifter in OD position they are not applied. In D, 2, and 1 position they are applied.

RBob.

Bjoern

Thanks Bob, I really appreciate your help!

This means, tearing down the trans again... I replaced the stock aluminium pistons with bonded steel ones and air checked everything. All good at this point. Well there must be something wrong somewhere of course. Manual first gear, all good, second gear as well. Only when it is in D I have a bind up.

Maybe someone of you guys can explain to me what's the benefit of replacing the 3rd accumulator feed with a freeze plug instead of a checkball capsula?! Didn't find much on the web, except people simply saying it's good or it's not.

Best
Bjoern

Pro Built Automatics

The problem when having a "bind" that stays on is usually the gasket not being checked to make sure that it did not cover any holes on the separator plate or a hole that is missing. I have seen plates with a hole missing and that kept the band from coming off and the 2-4 band was burnt and the drum ruined. The other reason is that 3-4 clutch pack is setup to tight, and this will only affect the 2-3 shift for a short time (a few tenths of a second) and will free up quickly. There is no benefit in installing the freeze plug. Always replace the third accumulator checkball capsule with another checkball capsule "if it cannot be saved". It gets rid of any cross leaking oil. In 700R4's the aluminum apply pistons are fine. I have only seen one crack in my life. With 4L60E's use the forward steel molded rubber piston with steel overrun piston or a billet forward aluminum piston with aluminum overrun piston. The aluminum 3-4 piston is fine in either transmission, and they never crack. The only reason GM went with the steel pistons is that they did not want to address the computer causing "spiking problems". In 4L80E's and AODE's TransGo offers a "high pressure relief valve" to solve the "spiking problems" in these transmissions. Again the "bottom line" coming first at GM instead of a real solution.