700R4 4x4 advice

[NMNorsse]

My 1988 K1500 7004r is due for a fluid and filter change. 60k original miles and 2 owners. I use it mainly to haul materials, tow and some occasional mild off roading. It drives fine right now and the fluid looks good. I just added an OEM auxiliary transmission cooler from the treasure yard.

When I drain it and drop the pan I'm planning on putting in the "TransGo 2-3" kit and a corvette servo but NOT going with the full manual option. The idea is put in their patented no-stick TV valve and to be able to hold 1st, 2nd or 3rd to whatever RPM when towing, off roading or for engine braking when coming down long grades (which are common where I live in the mountain west).

I'm no transmission expert but I can wrench. So, I would appreciate any suggestions or insights before I jump into this project.

 

[NickTransmissions]

My 1988 K1500 7004r is due for a fluid and filter change. 60k original miles and 2 owners. I use it mainly to haul materials, tow and some occasional mild off roading. It drives fine right now and the fluid looks good. I just added an OEM auxiliary transmission cooler from the treasure yard.

When I drain it and drop the pan I'm planning on putting in the "TransGo 2-3" kit and a corvette servo but NOT going with the full manual option. The idea is put in their patented no-stick TV valve and to be able to hold 1st, 2nd or 3rd to whatever RPM when towing, off roading or for engine braking when coming down long grades (which are common where I live in the mountain west).

I'm no transmission expert but I can wrench. So, I would appreciate any suggestions or insights before I jump into this project.

Yes, make sure you run minimal band clearance (1/8 longitudinal travel on the drum or a little less as long as the band doesn't drag (the shift kit will come w/one or two golden spacers to set band clearance). Spring for a servo 'D-ring' viton seal kit for the servo - nice little upgrade over the scarf-cut teflon sealing rings... While you're under there, install a Sonnax 1/2 o-ringed boost valve and .390 reverse boost valve kit as well as a Sonnax plunger and sleeve kit in the VB (Sonnax part number 77966-94k). Transgo may have those boost/rev boost valve parts in the 2-3 kit but I haven't used it in ages so don't know off-hand.

Do not tow in overdrive (you prob know that but in case you didn't). But if you absolutely need to for whatever reason, add a Sonnax 4th gear billet servo kit to give you much more apply surface area in 4th compared to the stock apply piston.

LMK if you have any quesitons...

 

[NMNorsse]

Yes, make sure you run minimal band clearance (1/8 longitudinal travel on the drum or a little less as long as the band doesn't drag (the shift kit will come w/one or two golden spacers to set band clearance). Spring for a servo 'D-ring' viton seal kit for the servo - nice little upgrade over the scarf-cut teflon sealing rings... While you're under there, install a Sonnax 1/2 o-ringed boost valve and .390 reverse boost valve kit as well as a Sonnax plunger and sleeve kit in the VB (Sonnax part number 77966-94k). Transgo may have those boost/rev boost valve parts in the 2-3 kit but I haven't used it in ages so don't know off-hand.

Do not tow in overdrive (you prob know that but in case you didn't). But if you absolutely need to for whatever reason, add a Sonnax 4th gear billet servo kit to give you much more apply surface area in 4th compared to the stock apply piston.

LMK if you have any questions...

Thank you! I'll check the Transgo 2-3 kit to see if it comes with the .500 boost or .390 reverse boost valves and pick up the Sonnax plunger/sleeve kit and 4th gear billet servo kit (just in case). I think the corvette servo comes with the D-ring Viton seal kit rather than the teflon scarf-cut ones.

Watching your Youtube Videos on the 700R4 valve body made me feel more comfortable about putting in the shift kit. I would recommend anyone thinking about doing something to their tranny watch your videos first.

I'm not sure how to check the band clearance, but if there is a video out there I'll find it and figure it out!

Thanks for the knowledgeable tips and for posting responses to other people's tranny questions.

 

[NMNorsse]

Thank you! I'll check the Transgo 2-3 kit to see if it comes with the .500 boost or .390 reverse boost valves and pick up the Sonnax plunger/sleeve kit and 4th gear billet servo kit (just in case). I think the corvette servo comes with the D-ring Viton seal kit rather than the teflon scarf-cut ones.

Watching your Youtube Videos on the 700R4 valve body made me feel more comfortable about putting in the shift kit. I would recommend anyone thinking about doing something to their tranny watch your videos first.

I'm not sure how to check the band clearance, but if there is a video out there I'll find it and figure it out!

Thanks for the knowledgeable tips and for posting responses to other people's tranny questions.

Band Clearance Question:

I'm going to reuse the factory pin when I put in the corvette servo.

Just did a little internet search and want to make sure I've got it right. My plan is to put a dial indicator on the servo cover (using a magnetic mount) after I install the corvette servo, depress the cover and see what the movement is- Between 1/8 and 1/16 its okay. Too little and I file down the tip of the pin. Too much, replace the pin or put a cap on it and make sure it is in the right range.

Is that correct?

Thanks in advance.

 

[NickTransmissions]

Thank you! I'll check the Transgo 2-3 kit to see if it comes with the .500 boost or .390 reverse boost valves and pick up the Sonnax plunger/sleeve kit and 4th gear billet servo kit (just in case). I think the corvette servo comes with the D-ring Viton seal kit rather than the teflon scarf-cut ones.

Watching your Youtube Videos on the 700R4 valve body made me feel more comfortable about putting in the shift kit. I would recommend anyone thinking about doing something to their tranny watch your videos first.

I'm not sure how to check the band clearance, but if there is a video out there I'll find it and figure it out!

Thanks for the knowledgeable tips and for posting responses to other people's tranny questions.

Thanks, man - appreciate the kind words. Confirm the vette servo you're buying does come with the d-ring seals as most come with the factory teflon scarf cut rings.

Band Clearance
Your summary above is correct though Sonnax recommends .075-.125 servo travel if measuring with a dial indicator on the cover.

Alternatively, you can also check band clearance by moving the band back and forth along the drum after installing the servo. You're looking for about 1/8" of travel. If its a quarter inch that's too much - use the gold shim that comes in the shift kit to tighten it up. If it's too tight after installing the gold ring and you can feel drag, grind a very small amt off the end of the pin and reinstall.

Leave all rubber/teflon sealing rings off of the servo when doing your test fitting! This way you won't damage them and will be easier to remove and reinstall multiple times for fitting.

 

[GMC_YA_L8R]

Yo, can I get a link to the aforementioned YouTube videos? I've looked around some and haven't been able to find one that's 4x4 700R4 specific other than one video for an S10 4x4 700R4. Are those identical?

 

[NickTransmissions]

Yo, can I get a link to the aforementioned YouTube videos? I've looked around some and haven't been able to find one that's 4x4 700R4 specific other than one video for an S10 4x4 700R4. Are those identical?

Those 700s in the S10s (assuming it was behind one of those gutless 60-degree V6 engines) are worthless...

Here's my 700R4 playlist...I cover a fair amount of info across a complete rebuild series plus a bunch of topical vids...let me know if you have any questions or need more info/clarification on anything.

 

[GMC_YA_L8R]

Those 700s in the S10s (assuming it was behind one of those gutless 60-degree V6 engines) are worthless...

Here's my 700R4 playlist...I cover a fair amount of info across a complete rebuild series plus a bunch of topical vids...let me know if you have any questions or need more info/clarification on anything.

Awesome! I'll definitely be watching this. Thanks, amigo!

 

[NickTransmissions]

Awesome! I'll definitely be watching this. Thanks, amigo!

You're welcome, man and thank you!

 

[NMNorsse]

UPDATED INFO:

The Vette Servo did come with the teflon scarf-cut seals so I ordered the Viton D-Ring Kit you linked to. $10 for the seals & $10 for shipping.

The Sonnax 4th gear servo kit replaces the 4th gear servo, runs $85 from Summit and comes with a d-ring seal. https://www.sonnax.com/parts/2473-4th-gear-super-hold-dual-servo-kit


The TransGo 2-3 kit does not include the .500 boost and .390 reverse valves. The kit DOES include their TV valve and two 3-2 valves- I assume one is for full manual operation and one for 'command shift' which keeps automatic shifting when you want it.

Sonnax has 2 TV sleeve/plunger kits- the part number you provided -k and a -mk. The difference appears just to be that the -mk prevents 4-3 downshift below 3/4 throttle. If I get the Sonnax sleeve/plunger kit do I use the TransGo TV valve?

The boost valve and reverse boost valves are sold separately or you can get the "Sure Cure" kit which includes both and a few other pieces.

Sonnax also has a upgraded 4l60 valve body which seems to include all that stuff (except the servo upgrades) and I'm wondering if that might be a better route than the TransGo 2-3 and individual parts?