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Help Tranny Guru's - 700R4 problems

the beast

the beast

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I just re-installed my 700R4 that I had built. My problem is that it's not shifting as I think it should with a shift kit installed and it shudders under moderate load. It's ok when cruising, or when given light pedal, but when you nail it I get a lot of vibration.

And yes, cause I know it's the first thing you'll ask, I adjusted the TV cable. twice.

We're at a bit of a loss here. :dunno:
 
Are you sure it is tranny and not axle wrap causing the vibes? If you rebuilt it you could have less slippage and more power through the driveline causing the axle to wrap up. Just a suggestion.

Ira
 
the beast said:
My problem is that it's not shifting as I think it should with a shift kit installed and it shudders under moderate load. It's ok when cruising, or when given light pedal, but when you nail it I get a lot of vibration.
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Can you be more specifc about how it's shifting, and how you expect it to shift? Also, what is the brand and model number of the shift kit?
 
I had it rebuilt be a pro, w/ a very good rep.

I expect the shifts to be firmer with a kit. This feels almost stock. I'm not sure of the kit. I think he said he combines parts out of B&M and Trans-go (?) kits.

It's a new convertor.
 
sandawgk5 said:
Are you sure it is tranny and not axle wrap causing the vibes? If you rebuilt it you could have less slippage and more power through the driveline causing the axle to wrap up. Just a suggestion.

Ira
Click to expand...

The vibe I think is too rapid to be caused by axle wrap. And it's not that severe. It's almost like a u-joint about to grenade, but I know those are good.
 
Is the TCC solenoid wired up(Tourque Converter Clutch).
Almost sounds like it's engageing too early.
Does this only happen after it goes into 4th or in all gears?

If mods have been done to the trans it's possible one of the wires to the pressure switches got connected wrong allowing the TCC solenoid to engage at too low of a pressure and RPM.
 
If you're sure the tv cable is adjusted properly check the line pressure at the port in the side of the trans. Don't remember exact specs but think somewhere around 100 psi warm in drive at idle. reverse will be higher. shift kit should probably raise it above specs a little. might also be worthwhile to check governor assy and be sure the valve in it isn't sticking
 
Did you install it or the shop? I'd check all fasteners first. I know it sounds dumb but if any are just slightly lose it humm. Especially the crossmember.
 
hate to change the subject..........:crazy:

but what does a normal shift for the 700 feel like

just wondering because mine shifts hard in all gears (depending on the skinny pedal position)
trans guy says it feels like a shift kit was installed in it
 
When i was running a 700r4 i had it rebuilt , And a corvette servo installed. It shifted so hard that it broke the carrier bearing off of two differentials in the stock 10 bolt rearend. When it was stock it shifted smooth as silk.
 
johnathan said:
mine locks up in drive or overdrive before fourth gear.What should I do,
check????:crazy: :crazy: :confused: :confused:
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some models are wired to lock up in 3rd and 4th, most however are wired to lock up in 4th.

it should lock up just before cruising speed, there are alot of different ways they are wired to lockup, and different speeds they lockup depending on what way its wired.
 
johnathan said:
What activates the lockup,can the lockup speed be changed?I never have liked it locking up that early.
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There are 3 pressure switches attached to the valve body they work along with a signal from the orig car's commputor.

My TCI 700R4 was wired up with one of their kit's.It takes a reading of manifold pressure and will only allow the trans to shift into O/D if there is enough vacume(low load).It also has to be in 4th.
There is an electrical solenoid that diverts fluid in the valve body to lock-up the Tourque Converter.Basically just 12v Pos. is needed to activate the TCC.
here is the kit I have on my 700R4
Look for the Universal Lockup Kit near the bottom of this page.
http://tciauto.com/gm/gm_4L60E.htm
http://tciauto.com/instructions/376600_inst.htm


The kit will allow me to wire it so it can go into O/D in 2nd,3rd or 4th but I didn't want that.
 
if you're concerned about the t/c clutch causing the problem try gently riding the brake pedal basically just enough to turn the brake lights on. the brake switch disables the tcc solenoid unless you have hydraulic leakage in the the trans from bad gaskets or cracked components
 
Bob, I plugged everything in. I'll re-check the connections.

GMC, I'll have to get that checked.

Southern, checked all the fasteners....twice.

Will driving it like this damage the tranny? I don't want to mess with the warranty.
 
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