700r4 Hydraulic Lock-up - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ChevyJr** · 10-08-2013, 01:27 PM

For those running a 700r4 hydraulic lock-up, what RPM are you running at 60mph?

I'm running a SBC 400, 3.08, 26" tires and hitting 22-2300 rpm @60. I think my TV cable has to be way off. It shift out of 1st at 5mph, out of 2nd at about 15-20 mph, and out of 3rd...well whenever it pleases. I've had it shift out of 3rd into OD at 27mph. And it has a performance shift kit, so I'm not guessing, I can feel it shift. Thanks for any info.

NEWFISHER · 10-08-2013, 03:41 PM

As you know, tire size and gear ratio greatly affect what your question is. There really is only one way to set up the t.v. cable and once set, its the mods inside the trans, grear ratio and tire size that effect the outcome. Other than the shifting out of 3rd at 27 mph, the rest seems a bit normal. I have run a boat load of 700r4's, tried to over haul them myself ( because they are just like a th350 right??,,,,uh no) and have finally steered away from internal modifications and aftermarket parts. I start with a good MD8 case and use GM internals. No problems. I have run the shaft/ball hydro lock up and pulled it and went with a B&M dial system that I had a trans shop set up for me. On the last one, I used a TCI harness and vacuum switch and it works great. On the next one I won't go hydro 4th lock or use B&M or TCI. I will wire it up myself and use the GM 85ish Gvan vac switch. Although expensive, the B&M adjustable system was pretty cool and could accommodate different tire size issues and hunting.

verdell · 10-08-2013, 06:01 PM

I ran a hydraulic lock up without much success. Ended up going with TCI harness and vacuum switch and turn about 2200 at 70 mph. This is with a 3.08 and 275 60 15 rear tires. My brother owns a '66 with a hydraulic lock up 700r4/3.08 rear and spins about the same as you. There's a noticeable difference between driving his '66 and my '60..

luvbowties · 10-09-2013, 05:22 AM

Quote:

Originally Posted by ChevyJr

For those running a 700r4 hydraulic lock-up, what RPM are you running at 60mph?

I'm running a SBC 400, 3.08, 26" tires and hitting 22-2300 rpm @60. I think my TV cable has to be way off. It shift out of 1st at 5mph, out of 2nd at about 15-20 mph, and out of 3rd...well whenever it pleases. I've had it shift out of 3rd into OD at 27mph. And it has a performance shift kit, so I'm not guessing, I can feel it shift. Thanks for any info.

You're right--sounds like you need to tighten throttle cable, as it's shifting waaay too soon. Better, with normal driving, would be around 12-15.....25-30......42-45. Best, I do not know: just telling you what I've experienced "the most" on oem trannies--where they seem to shift well.
Sam

kieth · 10-09-2013, 11:52 AM

Quote:

Originally Posted by ChevyJr

For those running a 700r4 hydraulic lock-up, what RPM are you running at 60mph?

I'm running a SBC 400, 3.08, 26" tires and hitting 22-2300 rpm @60. I think my TV cable has to be way off. It shift out of 1st at 5mph, out of 2nd at about 15-20 mph, and out of 3rd...well whenever it pleases. I've had it shift out of 3rd into OD at 27mph. And it has a performance shift kit, so I'm not guessing, I can feel it shift. Thanks for any info.

If you will pm me here on the board your e mail address I will send you a custom speed and torque for your truck including tire diameter , trans ratio, & rear axle ratio.... I would guess your truck at 350hp but let me know and I will also show you torque to the ground data. Kieth

the only reason for the e mail is I cannot post a excell file on this board

10-08-2013, 01:27 PM	#1
ChevyJr Junior Member Join Date: Feb 2013 Location: Minneapolis Posts: 87	700r4 Hydraulic Lock-up For those running a 700r4 hydraulic lock-up, what RPM are you running at 60mph? I'm running a SBC 400, 3.08, 26" tires and hitting 22-2300 rpm @60. I think my TV cable has to be way off. It shift out of 1st at 5mph, out of 2nd at about 15-20 mph, and out of 3rd...well whenever it pleases. I've had it shift out of 3rd into OD at 27mph. And it has a performance shift kit, so I'm not guessing, I can feel it shift. Thanks for any info.

10-08-2013, 03:41 PM	#2
NEWFISHER Registered User Join Date: Sep 2012 Location: Oregon Posts: 3,303	Re: 700r4 Hydraulic Lock-up As you know, tire size and gear ratio greatly affect what your question is. There really is only one way to set up the t.v. cable and once set, its the mods inside the trans, grear ratio and tire size that effect the outcome. Other than the shifting out of 3rd at 27 mph, the rest seems a bit normal. I have run a boat load of 700r4's, tried to over haul them myself ( because they are just like a th350 right??,,,,uh no) and have finally steered away from internal modifications and aftermarket parts. I start with a good MD8 case and use GM internals. No problems. I have run the shaft/ball hydro lock up and pulled it and went with a B&M dial system that I had a trans shop set up for me. On the last one, I used a TCI harness and vacuum switch and it works great. On the next one I won't go hydro 4th lock or use B&M or TCI. I will wire it up myself and use the GM 85ish Gvan vac switch. Although expensive, the B&M adjustable system was pretty cool and could accommodate different tire size issues and hunting.

10-08-2013, 06:01 PM	#3
verdell Registered User Join Date: Feb 2013 Location: Columbus, MS Posts: 443	Re: 700r4 Hydraulic Lock-up I ran a hydraulic lock up without much success. Ended up going with TCI harness and vacuum switch and turn about 2200 at 70 mph. This is with a 3.08 and 275 60 15 rear tires. My brother owns a '66 with a hydraulic lock up 700r4/3.08 rear and spins about the same as you. There's a noticeable difference between driving his '66 and my '60..



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