700R4 Information Thread

[Soundmound]

Following. I have TCC lockup issue with my 700 and want to try the switch to avoid rebuilding for a bit.

 

[SirRobyn0]

Yes, it shouldn't be shifting while TCC is locked up...TCC applies while in third, unlocks once you accelerate sufficiently -->shift to 4th--> TCC applies while in 4th. Downshift TCC apply strategy is the same.

Are you having issues w/your TCC lock up or just wanting to know more about how it all works?

No issues my TCC lock up works just fine. So yes my questions were just academic.

 

[NickTransmissions]

Following. I have TCC lockup issue with my 700 and want to try the switch to avoid rebuilding for a bit.

What's wrong with your TCC lock up?

Is it simply not locking up or locking and staying locked up when it shouldn't?

Or something else?

 

[SirRobyn0]

@Soundmound If you need any info from me regarding what we saw at the shop with your TCC let me know and I'll pull your file up.

 

[Soundmound]

What's wrong with your TCC lock up?

Is it simply not locking up or locking and staying locked up when it shouldn't?

Or something else?

Not 100% sure but SRO might be able to zero in.

@Soundmound If you need any info from me regarding what we saw at the shop with your TCC let me know and I'll pull your file up.

That would be awesome sir!

 

[NickTransmissions]

Not 100% sure but SRO might be able to zero in.


That would be awesome sir!

Yep, just saw his response. No worries, I imagine you/he can resolve but feel free to post any questions here if need be...

 

[SirRobyn0]

@Soundmound @NickTransmissions So we had Dave's truck in the shop on 10-19-22 We did a number of things to it but my notes say "Check inspect and repair transmission lock up. Vehicle came in with lock up disconnected because of converter shake / shudder. Solution is to have the converter replaced and / or transmission rebuilt and the converter replaced. "

To paraphrase TCC is unplugged (I assume at the transmission) and it's because there is a vibration when it is plugged in. So that's an internal issue and not something that could be mitigated with a manual apply switch. Hopefully that helps.

 

[NickTransmissions]

@Soundmound @NickTransmissions So we had Dave's truck in the shop on 10-19-22 We did a number of things to it but my notes say "Check inspect and repair transmission lock up. Vehicle came in with lock up disconnected because of converter shake / shudder. Solution is to have the converter replaced and / or transmission rebuilt and the converter replaced. "

To paraphrase TCC is unplugged (I assume at the transmission) and it's because there is a vibration when it is plugged in. So that's an internal issue and not something that could be mitigated with a manual apply switch. Hopefully that helps.

Gotcha...Yep, replace the converter asap as the TCC sounds like it's slipping as leaving it unplugged just results in runaway overheating and stresses the front gear train and clutch packs in the forward and rev input drums.

 

[tadslc]

Very interesting information, thanks!

And this is coming from someone that knows nothing about automatic transmissions. Never to old to learn though.

I'm getting a 700R4 installed in my truck as we speak and I've read all the horror stories on this forum about them, has me a little concerned.

 

[NickTransmissions]

Very interesting information, thanks!

And this is coming from someone that knows nothing about automatic transmissions. Never to old to learn though.

I'm getting a 700R4 installed in my truck as we speak and I've read all the horror stories on this forum about them, has me a little concerned.

As long as the installer sets up and adjusts the TV cable correctly and validates the set up via a transmission pressure gauge, taking readings at idle and full TV for each range setting, it will be fine...Readings should be 50-70 PSI in P, N, D while R should be 100-120PSI and manual low/manual 2nd should be 160-185 PSI or so...if not set up right, trans can potentially burn up in as little as 5 minutes of driving.

 

[Radiohead]

This is a fun thread as well as mentally nutritious. I love learning the nuances of things, since I never got intimate with transmissions much like SRO. I still have the ASE Master cert from back in the day although I let my certs drop in '08, so I'm not going into any of this blind. Thanks again Nick for offering up your gold for our troubles.

Just wait, I have my questions about th400 in the queue. As well as stick boxes, but that too is for another time.

 

[NickTransmissions]

This is a fun thread as well as mentally nutritious. I love learning the nuances of things, since I never got intimate with transmissions much like SRO. I still have the ASE Master cert from back in the day although I let my certs drop in '08, so I'm not going into any of this blind. Thanks again Nick for offering up your gold for our troubles.

Just wait, I have my questions about th400 in the queue. As well as stick boxes, but that too is for another time.

Thanks, man and stay tuned. I'll be uploading a teardown and inspection of a TH475 to my YT channel in a couple weeks...

 

[dperry9350]

My 86 C10 came with 305, 3 speed, and 273 rear end. I’m upgrading to a 350, and to make it more fun light to light I want to go to a 373 or 410 rear end. And still be able to cruise down the highway without running the RPM’s too high. So I got a freshly rebuilt 700R4 that’s good for up to 500hp, with a mild shift kit. I’ve got the TV cable hooked up but how do I wire up the TCC? At first I was told I could just run a transmission cooler to help keep it cooler and I wouldn’t need to worry about the TCC… but I’m thinking it would be better to have it hooked up properly… thanks in advance for any advice!

 

[NickTransmissions]

My 86 C10 came with 305, 3 speed, and 273 rear end. I’m upgrading to a 350, and to make it more fun light to light I want to go to a 373 or 410 rear end. And still be able to cruise down the highway without running the RPM’s too high. So I got a freshly rebuilt 700R4 that’s good for up to 500hp, with a mild shift kit. I’ve got the TV cable hooked up but how do I wire up the TCC? At first I was told I could just run a transmission cooler to help keep it cooler and I wouldn’t need to worry about the TCC… but I’m thinking it would be better to have it hooked up properly… thanks in advance for any advice!

I'd love to sample what whoever gave you that advice about the converter is smoking...unlike the TH350C, the 700R4 must have a functioning tcc lock up mechanism or a tcc non-lock up conversion kit installed.

What year is your 700R4?

What TCC lock up kit did you purchase (if any)?

82-87 had valve bodies where you were able to control tcc lock up via the L/U control valve in the valve body. 88+ were not provisioned for that.

I would add a cooler if you live in a warm weather state or using the vehicle for racing/street strip/heavy duty towing/hauling...

What's your overall rear tire diameter?

3.73 is a good overall ratio, nice acceleration (esp with a mid-to-high stall converter) while keeping rpms to around 2200 at 70 mph depending on tire size. 4.10 is more agressive, suitable for street strip or towing/hauling...this all assumes stock tire diameter.

Have you done a pressure test to comfirm TV adjustment?

 

[dperry9350]

I'd love to sample what whoever gave you that advice about the converter is smoking...unlike the TH350C, the 700R4 must have a functioning tcc lock up mechanism or a tcc non-lock up conversion kit installed.

What year is your 700R4?

What TCC lock up kit did you purchase (if any)?

82-87 had valve bodies where you were able to control tcc lock up via the L/U control valve in the valve body. 88+ were not provisioned for that.

I would add a cooler if you live in a warm weather state or using the vehicle for racing/street strip/heavy duty towing/hauling...

What's your overall rear tire diameter?

3.73 is a good overall ratio, nice acceleration (esp with a mid-to-high stall converter) while keeping rpms to around 2200 at 70 mph depending on tire size. 4.10 is more agressive, suitable for street strip or towing/hauling...this all assumes stock tire diameter.

Have you done a pressure test to comfirm TV adjustment?

This is the transmission that I bought. With a 2,200 stall converter. https://www.ebay.com/itm/175836827581 I can reach out to them tomorrow and find out what style TCC kit it came with. And I already bought the trans cooler, so I’m still gonna install it anyways.

Haven’t even started to venture down the wheels and tires road yet… sooo much out there to choose from.

I haven’t fired up the new engine yet. Installed roller rockers on it right after I sat the engine down in the truck. So I’ve gotta adjust the valves and finish up all the other odds and ends before firing it up. Just got done installing all new gauges and wiring them up. Plus stripping all the extra junk off the engine harness and putting new loom on it. Getting pretty close to the first time turning it over. So once it’s running I will make sure to figure out how to do the pressure test and adjust the TV cable.

Also, I just thought about it. Can I just fill the trans with fluid. Or is there a certain way I should go about it…?? Thanks!!! So informative.