700R4 Information Thread

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Ricko1966

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I'm slow, it took me a minute to figure what the **** was in your post. I was going to correct it and use a 0 in **** but then realized, if you take the space out that doesn't belong, we can say cockeyed. :lol:

Oh, and I guess the filter is smarter than us and we can't Kock. Cuz even using a Zero for the O, it's still ****.
Yes I did laugh out loud. Good info. Thanks.
 

chevytech87

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So I’ve got a dumb question. I put my new transmission in today and it’s doing something strange. If I accelerate at a normal rate in OD it short shifts aggressively, 4th at 20 MPH. In regular drive it seems* to be okay, shifting somewhat normally, then I can bump it in to OD and roll along. I noticed that there is no governor cover, just a metal disc in its location. Am I crazy, or is it likely that I was sent a manual shift trans? Only thing that’s making any sense to me here.
 

Ricko1966

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So I’ve got a dumb question. I put my new transmission in today and it’s doing something strange. If I accelerate at a normal rate in OD it short shifts aggressively, 4th at 20 MPH. In regular drive it seems* to be okay, shifting somewhat normally, then I can bump it in to OD and roll along. I noticed that there is no governor cover, just a metal disc in its location. Am I crazy, or is it likely that I was sent a manual shift trans? Only thing that’s making any sense to me here.
It's not a manual valve body,otherwise you'd be taking off in 3rd. Idk the answer to your problem have you verified TV cable adjustment to line pressure? That's where I'd start.
 
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NickTransmissions

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So I’ve got a dumb question. I put my new transmission in today and it’s doing something strange. If I accelerate at a normal rate in OD it short shifts aggressively, 4th at 20 MPH. In regular drive it seems* to be okay, shifting somewhat normally, then I can bump it in to OD and roll along. I noticed that there is no governor cover, just a metal disc in its location. Am I crazy, or is it likely that I was sent a manual shift trans? Only thing that’s making any sense to me here.
Take a pic of the metal disc then remove it - take another pic of what's behind it and post them both here.

Assumimg you are looking at the governor and not the speedo housing bore, I'm curious to see what you're seeing.
 

chevytech87

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It's not a manual valve body,otherwise you'd be taking off in 3rd. Idk the answer to your problem have you verified TV cable adjustment to line pressure? That's where I'd start.
Planning on sticking a gauge on it Monday to see what’s going on, didn’t have mine at the shop yesterday. TV cable seems to be adjusted properly, but I know pressure verification is the only way to know for sure.
Take a pic of the metal disc then remove it - take another pic of what's behind it and post them both here.

Assumimg you are looking at the governor and not the speedo housing bore, I'm curious to see what you're seeing.

Will do, I’m curious to see what’s under it. Hopefully I’ll have some answers tomorrow.
 

chevytech87

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Mystery solved. Kind of.

The governor cover was smashed, which is what looked weird. Must have happened in transit and I just spaced and didn’t realize until it was in the truck. I swapped it out, governor didn’t look damaged. Then I unplugged the lock-up wiring. Drives great with it unplugged. So, somethings up with the lockup wiring. Going to re-wire, make sure everything is where it should be, and re-test. Also verified again that the TV cable is where it should be. Did some minor adjusting after unplugging the lockup, everything seems dialed. Good news is the transmission seems fine, was really sweating that one for a minute!
 

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Hi,
I have had a professionally rebuilt and strengtened th700 for a while, but it wont shift to the 4th gear or lockup the converter. At first I thought that it shifts to the fourth, as it feels like downshifting when I engine brake and move the shifter from OD to D. There is a soft jerk that feels like downshifting, albeit a lot milder than that of the 3to2 or 2to1. However when accelerating I've never felt the upshift to 4th and I have 4000 revs at 85mph which tells that I'm still on 3th (31in tires, 4.11 gear).

I have tried slightly looser TV cable and a bit too tightly set one that almost prevents all the upshifts. All without results.

At we first we thought that we had started with a too loose tv cable and burnt something, even though the oil looked just fine. So the transmission was taken off the truck, taken apart and checked by an another professional but everything seemed to be ok. But there's still no 4th gear.

Another problem (linked or not?) is that the converter (Boss Hog 48453, 2800-3200stall) does not lockup. The trans has a tci vacuum kit installed, the red wire gets power and I've tried both the overdrive vacuum switch and grounding the green wire that shoud lockup 2,3 and 4, all without results.

This is getting a bit frustrating, any help is appreciated.
 

NickTransmissions

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Hi,
I have had a professionally rebuilt and strengtened th700 for a while, but it wont shift to the 4th gear or lockup the converter. At first I thought that it shifts to the fourth, as it feels like downshifting when I engine brake and move the shifter from OD to D. There is a soft jerk that feels like downshifting, albeit a lot milder than that of the 3to2 or 2to1. However when accelerating I've never felt the upshift to 4th and I have 4000 revs at 85mph which tells that I'm still on 3th (31in tires, 4.11 gear).

I have tried slightly looser TV cable and a bit too tightly set one that almost prevents all the upshifts. All without results.

At we first we thought that we had started with a too loose tv cable and burnt something, even though the oil looked just fine. So the transmission was taken off the truck, taken apart and checked by an another professional but everything seemed to be ok. But there's still no 4th gear.

Another problem (linked or not?) is that the converter (Boss Hog 48453, 2800-3200stall) does not lockup. The trans has a tci vacuum kit installed, the red wire gets power and I've tried both the overdrive vacuum switch and grounding the green wire that shoud lockup 2,3 and 4, all without results.

This is getting a bit frustrating, any help is appreciated.
When was this trans rebuilt?

Is it still under warranty from the shop that built it?

The no-OD and no L/U may be related. For whatever reason, if you don't wire up the lock up kit correctly, sometimes the trans won't shift into overdrive...See this occasionally in 200-4Rs as well. That said, check your TV cable geometry...This has to be spot on. If your truck has the original engine and carb then there shouldn't be any geometry issues.

Next - Did you conduct a pressure test to validate your TV cable adjustments are correct?

No OD, all other things done correctly and TV cable set up/adjustment done right, can be caused by the following:
- Worn pump, boost valve, pressure regulator valve or working surfaces
- 3-4 relay valve installed backwards
- Worn/sticking TV boost valve
- Worn, leaky TV plunger and/or sleeve
- Worn or excessive clearance in 3-4 clutch
- Worn or torn teflon sealing ring in the 4th gear servo apply piston just inside the cover
- Worn or torn rubber o-ring style seal on the 4th accumulator piston
- Misplaced or missing check balls
- Bad valve body (no pin-pointable cause or causes)
 

chevytech87

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So I re-did the lockup wiring with a vacuum switch in place of the factory ecm. This yielded the exact same result as before. As soon as I hit 4th, converter locks. Short shifting, weird jerky shifts. But, unplug the connector at the transmission, normal operation sans lockup. I’m stumped. What am I missing?
 

Ricko1966

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So I re-did the lockup wiring with a vacuum switch in place of the factory ecm. This yielded the exact same result as before. As soon as I hit 4th, converter locks. Short shifting, weird jerky shifts. But, unplug the connector at the transmission, normal operation sans lockup. I’m stumped. What am I missing?
Pull the lockup solenoid,see if someone added a checkball above it. It's a backyard trick for automatic,4th gear lockup
 

HotRodPC

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Transmission mount is ~3/4" further back on a 700R4 than it is on a TH350. Both TH350 and 700R4 were available in 84, and it was the last year for the TH350. You could look at your SPID sheet to see what one your truck came with from the factory. MD8 or MX0 is the RPO for a 700R4. MX1/M38/M49 are the RPO's for a TH350. M40 is the RPO for a TH400

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I've had this chart for years. Comes in handy bigtime to make swaps and know what you need to do about your driveshaft length if you swap.
 

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