700R4 Transmission Will Not Shift Out Of 1st Gear Unless Going Down A Bridge And No Reverse

[blackandgold51]

1990 GMC Suburban 4x4 350 V1500 can go foward but no upshift unless having a "push" downhill acceleration. I can go 35 mph but i dont want to go over 40 because of fear of other damages.

Should i stick with a 700r4 or go Turbo 400? 700r4 was rebuilt back in november 2013 last owner said gear could come out of second gear.

And on the highway i mosly go 70 to 75 mph

 

[kennyw]

If you rebuild the 700, just make sure everything possible is upgraded. I doubt a 400 would work well at 70-75 mph unless you enjoy listening to your motor scream.

 

[blackandgold51]

If you rebuild the 700, just make sure everything possible is upgraded. I doubt a 400 would work well at 70-75 mph unless you enjoy listening to your motor scream.

Just got another 700r4 that has been built from the transmission shop with 6 month warrenty. Its been built heavy duty for corvettes and hotrod and has a "wideband" dont kniw what that means though

 

[kennyw]

Just got another 700r4 that has been built from the transmission shop with 6 month warrenty. Its been built heavy duty for corvettes and hotrod and has a "wideband" dont kniw what that means though

So it is a 2wd?

 

[blackandgold51]

No 4x4

So it is a 2wd?

 

[kennyw]

No 4x4

I've never seen a 4x4 Corvette... do you mean Corvette servo? I think that just speeds up the shift timing and doesn't do much for longevity in a truck. I know you will spend at least $1500 and upwards of $3000 to build a 700 to last in a truck depending on what you start with. If you bought it used, I would not expect it to last over a year. Anything after that is a bonus.

 

[blackandgold51]

I've never seen a 4x4 Corvette... do you mean Corvette servo? I think that just speeds up the shift timing and doesn't do much for longevity in a truck. I know you will spend at least $1500 and upwards of $3000 to build a 700 to last in a truck depending on what you start with. If you bought it used, I would not expect it to last over a year. Anything after that is a bonus.

Guy said he will change the servo and shaft.

This is the list of the features of this 700r4:

700R4 HP Transmission

600 HP Ready

All Hydraulic Unit

Shift Kited

Super Servo

Super Wide Band

HD Input Drum

6 Months Warrenty

And its NOT used. Its new but been built

 

[sweetk30]

you need to get input from our tranny guy here @Greg Ducato

 

[Heavyleft]

I have been running the same 700r4 in my K5 for 5 years now after two prior 700r4s. I found a guy that has been in the Trans rebuild business for 30 years and has done countless race/track transmission builds. Told him what kind of abuse it will be taking and he hooked it up and I have had no issues since. Mine was a $900 bench job. It will be more if they pull the trans.

Gotta find that old guy with decades of experience. I will never do an off the shelf company again.

 

[Blue85]

Guy said he will change the servo and shaft.

This is the list of the features of this 700r4:
700R4 HP Transmission
600 HP Ready
All Hydraulic Unit
Shift Kited
Super Servo
Super Wide Band
HD Input Drum
6 Months Warrenty
And its NOT used. Its new but been built

Which shaft - the input shaft? 600HP probably means NA (not supercharged). They really should rate them to torque, not HP, but probably doesn't matter unless you've been breaking hard parts. Never heard of putting a kite inside a transmission. They should tell you exactly what "shift kit" they will use Discuss this with them because there are a lot of features you can add or change in the process, like better compression braking, ability to get back into 1st without a complete stop, etc. I assume the drum and band are a matched set, which is how they make it work. Ask them exactly what frictions they will put in, too. Get it all in writing so you know exactly what they will and won't do. Hopefully their work is better than their spelling.

 

[Greg Ducato]

Any 700R4 will hold 600HP, the question is...for how long? An honest 600HP is at the extreme top range of a radically built 700R4. I would estimate a build of that nature to run in the area of $2500-$3K. You cant cheat physics.

 

[Greg Ducato]

To your orginal post, if your trans will upshift going fast enough downhill I would have a look at the governor gear, that is a $5 fix

 

[rjfguitar]

Uh yeah, sounds like a stripped governor gear to me, if memory serves....

 

[Blue85]

But he also says there is no reverse.

 

[Greg Ducato]

I didn't think he mentioned reverse in his first post

 

[sweetk30]

But he also says there is no reverse.

found it . . . . its in the title of the thread .

 

[Greg Ducato]

No wonder I didn't see it, the letters were too large and in bold typeface

 

[Greg Ducato]

No reverse on a 700R4 means trans needs real help, unless by some phenomenon the small plate or Aux valve body at the rear of the case is loose, this will vent both governor pressure and reverse apply pressure.

 

[campfire]

Which shaft - the input shaft? 600HP probably means NA (not supercharged). They really should rate them to torque, not HP, but probably doesn't matter unless you've been breaking hard parts. Never heard of putting a kite inside a transmission. They should tell you exactly what "shift kit" they will use Discuss this with them because there are a lot of features you can add or change in the process, like better compression braking, ability to get back into 1st without a complete stop, etc. I assume the drum and band are a matched set, which is how they make it work. Ask them exactly what frictions they will put in, too. Get it all in writing so you know exactly what they will and won't do. Hopefully their work is better than their spelling.

This sums up my thoughts.

 

[campfire]

Gotta find that old guy with decades of experience. I will never do an off the shelf company again.

This. The reason that I ended up with my $1 K10 is that a previous cheap hack-job of a tranny repair failed (700R4). Throwing parts at it is not enough, find someone who knows that particular tranny and hire a good rebuilt if you plan on keeping the truck on the road.

And I'd strongly encourage you to research each and every upgrade that is put into a transmission. Each one will affect the tranny's behavior. Be sure that you actually want a corvette servo before shelling out bucks for random "upgrades."

Anyone can write up an advertisement with 15 magic buzz words. But that doesn't mean that he knows what he's doing. If he can't explain, in simple language, what every upgrade does, he's not worthy of your dollars. Find someone who can do such. You don't want a 600HP tranny (and HP without a torque rating is a worthless measurement anyways). You want a tranny that lasts for a long time. Someone just spouting performance numbers with a sketchy amount of misspelled details does not merit any of my confidence.