700r4 junkyard pull looks new inside...

[suburban99]

Hey all, I pulled a 1991 700r4 out of a 4x4 sierra at the U-pull for $69.00 truck was in good shape other than a collision in rear box. Motor had just had work done as many new parts were attached and it was clean.

Disassembled 700R4 and pan was completely clean, gasket looked new. Pulled apart the tranny and the clutches and steels look new. All bushings look new. The band has TH700R in clear paint on it. All the gears and sunshell looks good, bearings look good. I am thinking of replacing the input and output seals and adding shift enhancements and corvette servo and running it? I had to disassemble anyway to change to the shorter output shaft to fit my 205...It's going in my 72 K10 6.0LS...currently running a TH350.

I am in no way an expert but it just looks good and I don't know if it will be any different of I add a rebuild kit. Your thoughts?

[YoungPup1977]

Take a look at this pic, you will notice two types of VB's used in a 700R4. The VB on the right has a provisioning for TCC shift valve, the other one does not. If your trans has the type on the right in the pic, you can buy a 700LU kit from Transgo which will allow the trans to use this shift vale to apply the TCC. This is used so you do not have to run any electrical connections to the trans at all.... you do not have to disengage the TCC thru the brake switch.....it works much better than vac switch setups....trust me, I have done many of these and they work great.

As far as your trans, you are installing it into a 4x4 vehicle...replace the sun shell, install a wider bushing in the sun gear (sonnax)....

You already have it apart, VB is off right, so you have to buy pump gasket, pump o-ring, seal, bushing, VB gaskets...... so why not buy a kit without the steels (only if the steels are good) and replace them. You can even go with bonded pistons (must buy different spring retainer) if you like and replace the existing pistons and lip seals....bonded pistons are easlier to install and better than lip seals....

Upgrade the 2/4 servo...
Install a shift kit, replace the existing TV valve.

"Maybe" consider replacing your 4 pinion planets with 5 pinions but not required.

Or you can take the "chance" and put the trans in with the AD output shaft and run it....

One more thing, I would suggest to leave the np205 TC in its original position in the frame....this will allow you to keep the TC shifter in the stock location and no cutting of the drive shafts...to accomplish this by moving the engine forward....and cutting your upper and lower radiator hoses.....easy!!!!!!

[Clyde65]

Why put a stock 700 behind a 6.0l in a 4x4? I would think a 4l80 or 400 would stand up to far more abuse or even spirited driving?

Just a question OP

[suburban99]

Originally Posted by Clyde65

Why put a stock 700 behind a 6.0l in a 4x4? I would think a 4l80 or 400 would stand up to far more abuse or even spirited driving?

Just a question OP

I think the Turbo 400 or 4L80E would be too long to keep the transfer case in stock position...the 700R4 is only 2" longer than the TH350 i have now...I can slide my engine forward 2"...(hopefully) 700R4 has a 3.06 to 1 first gear and .70 OD... Truck runs 35's.

[suburban99]

Originally Posted by YoungPup1977

Take a look at this pic, you will notice two types of VB's used in a 700R4. The VB on the right has a provisioning for TCC shift valve, the other one does not. If your trans has the type on the right in the pic, you can buy a 700LU kit from Transgo which will allow the trans to use this shift vale to apply the TCC. This is used so you do not have to run any electrical connections to the trans at all.... you do not have to disengage the TCC thru the brake switch.....it works much better than vac switch setups....trust me, I have done many of these and they work great.

As far as your trans, you are installing it into a 4x4 vehicle...replace the sun shell, install a wider bushing in the sun gear (sonnax)....

You already have it apart, VB is off right, so you have to buy pump gasket, pump o-ring, seal, bushing, VB gaskets...... so why not buy a kit without the steels (only if the steels are good) and replace them. You can even go with bonded pistons (must buy different spring retainer) if you like and replace the existing pistons and lip seals....bonded pistons are easlier to install and better than lip seals....

Upgrade the 2/4 servo...
Install a shift kit, replace the existing TV valve.

"Maybe" consider replacing your 4 pinion planets with 5 pinions but not required.

Or you can take the "chance" and put the trans in with the AD output shaft and run it....

One more thing, I would suggest to leave the np205 TC in its original position in the frame....this will allow you to keep the TC shifter in the stock location and no cutting of the drive shafts...to accomplish this by moving the engine forward....and cutting your upper and lower radiator hoses.....easy!!!!!!

Thanks...all good info for a novice rebuilder..(60 year old novice)...

[YoungPup1977]

The 700R4 will hold up fine.....it appears the 700R4 gets a bad rap. maybe because if the TV cable is not adjusted correctly the trans will not last long. The 3/4 clutches will be the first to go. But this is the way the 700R4 was designed to work with the TV cable, before the release of the 4L60E.

I have a 700R4 behind a 425 hp 383, (700R4 in all three of my blazers) its been in my 1972 c10 for 2 years without any issues....maybe I am lucky because I rebuild transmissions and know how to make them last...

[suburban99]

Looks like I have the other valve body...I guess I have to use the solenoid for lock up?

[suburban99]

I am running an LS in the truck and the PCM has a pin for TCC lock..(pin 2 on red connector I believe)..

[Bigdav160]

Yes, you'll need torque converter lockup to be functional. Electric in your case. Are you going to keep the fuel injection? Computer control would easiest. Two switch (NO&NC) brake switch works as a power source.

It'll be really important that you have a good cooler system on that trans. They run hot with the converter unlocked.

I also recommend a Transgo 700 junior shift kit.

[suburban99]

Originally Posted by Bigdav160

Yes, you'll need torque converter lockup to be functional. Electric in your case. Are you going to keep the fuel injection? Computer control would easiest. Two switch (NO&NC) brake switch works as a power source.

It'll be really important that you have a good cooler system on that trans. They run hot with the converter unlocked.

I also recommend a Transgo 700 junior shift kit.

Yes I am running the stock fuel injection and PCM from the 2003 donor...runs great with the TH350 just no OD...

[YoungPup1977]

I dont know how you are connected........How is the computer going to know when to lockup the TCC, just wondering on how you are connected since the 700R4 doesn't have a VSS. 700R4 uses a gov and TV valve for upshifts. With the pin 2 mentioned, is it ground/voltage and how is it controlled. The problem with wiring to the 4th gear oil circuit in the VB is....it applies the TCC as soon as OD is applied....in town driving you will not like the results...my opinion only.

Maybe find a junkyard pull on a 4L60E....Do you have the entire wiring harness for the LS which includes the wiring harness for the transmission ?

[suburban99]

Originally Posted by YoungPup1977

I dont know how you are connected........How is the computer going to know when to lockup the TCC, just wondering on how you are connected since the 700R4 doesn't have a VSS. 700R4 uses a gov and TV valve for upshifts. With the pin 2 mentioned, is it ground/voltage and how is it controlled. The problem with wiring to the 4th gear oil circuit in the VB is....it applies the TCC as soon as OD is applied....in town driving you will not like the results...my opinion only.

Maybe find a junkyard pull on a 4L60E....Do you have the entire wiring harness for the LS which includes the wiring harness for the transmission ?

I am using the Dakota Digital VSS connected to the speedo cable...it gives a signal to the PCM...yes I have the complete wiring harness from the donor. I am thinking maybe I need to swap the valve body to the other style?

[YoungPup1977]

the cost of the VB will be more than what you paid for the 700R4....maybe go get yourself a junkyard pull 4L60E, only 69 bucks....thats cheaper than the VB for the 700R4. Build the junkyard pull 4L60E to shift correctly and last long time. Done !!! Good Luck.

[suburban99]

The main reason for the 700r4 was the low first gear..(and the OD)
I think I'll see if I can get a valve body reasonable...now that I know what I'm looking for..

[Bigdav160]

Nothing wrong with your valve body.

And the gearing is the same as the 4L60e.

The problem with either trans is you'll lose the VSS in a short output shaft 4WD configuration.

[YoungPup1977]

Originally Posted by Bigdav160

Nothing wrong with your valve body.

And the gearing is the same as the 4L60e.

The problem with either trans is you'll lose the VSS in a short output shaft 4WD configuration.

The VSS was stated in a earlier post it was going to be off the speedo cable which would be off the np205 transfer case.....not the TRANS....... The Advance Adapter output shaft will work in both the 700R4 or the 4L60E trans.....it has the provisioning in the shaft for the gov which the 4l60E does not use a gov.......

the 4 bolt pattern on rear of the 1995 - 1999 4L60E is the same as the 700R4 so no issue there bolting up to the np205..... no need to drill a hole in the case for a VSS to work off the output shaft when it can work off the TC speedo ..... Just my 2 cents...Thanks.

[YoungPup1977]

I am assuming the Dakota digital VSS is a Pass thru pulse generator which is connected to the existing "OLD" type of speedo cable at the np205 transfer case.

As far as the gear ratio's....the planetary gear ratio's in the 700R4 are the same as the 4L60E.....there are some differences regarding 4/5 pinion planets, sun shell upgrades with torrington bearing replacing the thrust washer, but the gear ratio's are all the same.

The reason I brought up the VB to be changed is two fold:
1. This would eliminate the requirement for any type of a VSS. 700R4 has a gov and tv cable for upshifting and down shifting.
2. TCC engagement/disengagement would be done thru the VB, "TCC shift valve addition to VB" which would eliminate any external requirement for TCC lockup/engagement/disengagement. (I know some want the brake switch but not required)

It appears the 700R4 is the trans of choice here and not the 4l60E so there really is no need for the VSS in my opinion....just to lockup the TC clutch ?

[suburban99]

I will use the TCC Convertor Solenoid pin #2 on red PCM connector to lock the convertor. This is a negative output from the PCM.
Yes the VSS is a pass thru Generator with a correction box mounted in the cab. The PCM needs to know how fast the vehicle is traveling, and when it's stopped.

[suburban99]

I’m going to test the TCC output with the TH350 still in the truck...
I will hook a test light to pin 2 red PCM connector and see when the lock and unlock command happens. Had an unfortunate encounter with a gigantic snow blower last week and am currently waiting on my Claim..