Any quick/easy way to diagnose a failing 700R4?
Thread Starter
Member
Joined: Jul 1999
Posts: 496
Likes: 0
From: Chicago, IL
Car: 89 IROC-Z
Engine: LB9
Transmission: 700-R4
Any quick/easy way to diagnose a failing 700R4?
I'm about 90% sure that my trans is slipping and on the way out. It stumbles a lot from gear to gear and sometimes won't shift until it revs really high but this revving doesn't produce quick acceleration. My dad thinks I might have just screwed up a vacuum hose or something when I swapped the intake, but I'm not even sure the 700R4 uses any engine vacuum to operate, and isn't the TCC the only computer controlled part? Thanks for any help, the HELM manual diagnosis is quite daunting so I don't know where to start with that, and I've heard firsthand that some shops tell their techs that whoever comes through the door gets a trans rebuild (yikes).
Also, I've found a guy that does rebuilds after hours (have it from a good source that his work is excellent) for cash and he said if there's no planetary damage he could do a basic rebuild for $300-400. Does this sound right? He said that's if I remove/reinstall the tranny, or else it would be $150-200 more.
That said, if I have this thing rebuilt, what are some goodies to put in there? He said a shift improver kit would be a good idea, and I'm also going to spring for a vette servo and upshift valve. When it's said that a tranny can handle X amount of horsepower, what goes into that number? I'm basically looking to support a little over 400 horsepower unless it's going to cost too much.
Thanks for any and all advice!
------------------
Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: Accel 300+ wires, cap&rotor
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, hopefully engine swap and 4th gen seats in the works...
[This message has been edited by I ROCK (edited January 27, 2001).]
Also, I've found a guy that does rebuilds after hours (have it from a good source that his work is excellent) for cash and he said if there's no planetary damage he could do a basic rebuild for $300-400. Does this sound right? He said that's if I remove/reinstall the tranny, or else it would be $150-200 more.
That said, if I have this thing rebuilt, what are some goodies to put in there? He said a shift improver kit would be a good idea, and I'm also going to spring for a vette servo and upshift valve. When it's said that a tranny can handle X amount of horsepower, what goes into that number? I'm basically looking to support a little over 400 horsepower unless it's going to cost too much.
Thanks for any and all advice!
------------------
Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: Accel 300+ wires, cap&rotor
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, hopefully engine swap and 4th gen seats in the works...
[This message has been edited by I ROCK (edited January 27, 2001).]
Member
Joined: Jan 2001
Posts: 142
Likes: 0
From: In The Garage
Car: 1986 IROC-Z
Engine: SBC
Transmission: Manual Th-350
Axle/Gears: 9" Moser 3.89's Spool.
this sounds like a commom case of not ajusting the TV Cable properly. If you just changed the intake then you had to have removed the TV cable from the TPI. This requires a reajustment of the linkage.
To reajust the TV cable push the little tab on the slider part of the cable that clips into the linkage bracket. Then slide the slider all the way into the housing. Then with the car off get in an put the gas to the floor. This should reajust you linkage but some older cables require you to reset the linkage and press lightly on the release clip when you floor it with the car off.
I have seen many transmissions do this and it has always been the TV Cable because that cable controls the whole transmission.
A haynes manual would be a good investment to check for other things you could try before you need a rebuild. Usally when these transmissions need a rebuild they shift so hard all the time that they break them selves.
IROC4LIFE
To reajust the TV cable push the little tab on the slider part of the cable that clips into the linkage bracket. Then slide the slider all the way into the housing. Then with the car off get in an put the gas to the floor. This should reajust you linkage but some older cables require you to reset the linkage and press lightly on the release clip when you floor it with the car off.
I have seen many transmissions do this and it has always been the TV Cable because that cable controls the whole transmission.
A haynes manual would be a good investment to check for other things you could try before you need a rebuild. Usally when these transmissions need a rebuild they shift so hard all the time that they break them selves.
IROC4LIFE
Thread Starter
Member
Joined: Jul 1999
Posts: 496
Likes: 0
From: Chicago, IL
Car: 89 IROC-Z
Engine: LB9
Transmission: 700-R4
Hey man,
Thanks a lot, now I'm almost certain you're right, b/c in the tech article I read it as "push in the tab and rotate the throttle to WOT but don't use the pedal" so basically I adjusted it backwards. Welcome to this site, it really ROCKS, as you'll see if you stick around, and thanks for making your first post a very valuable one to me! Later
------------------
Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: Accel 300+ wires, cap&rotor
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, hopefully engine swap and 4th gen seats in the works...
Thanks a lot, now I'm almost certain you're right, b/c in the tech article I read it as "push in the tab and rotate the throttle to WOT but don't use the pedal" so basically I adjusted it backwards. Welcome to this site, it really ROCKS, as you'll see if you stick around, and thanks for making your first post a very valuable one to me! Later
------------------
Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: Accel 300+ wires, cap&rotor
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, hopefully engine swap and 4th gen seats in the works...
Thread Starter
Member
Joined: Jul 1999
Posts: 496
Likes: 0
From: Chicago, IL
Car: 89 IROC-Z
Engine: LB9
Transmission: 700-R4
Yep that was it - thanks a million! I was so happy I even used the car to deliver pizzas for 9 hours tonight which I never do!
------------------
Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: Accel 300+ wires, cap&rotor
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, hopefully engine swap and 4th gen seats in the works...
------------------
Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: Accel 300+ wires, cap&rotor
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, hopefully engine swap and 4th gen seats in the works...
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