overdrive opinion

[SCOTI]

Originally Posted by jimijam00

Lol. What's even scarier, you and I seem to be the only two that know that.

I bet there's just as many of us that know as there are of those that don't believe it or pay attention enough to realize.

[ChevyRacefan]

Originally Posted by jimijam00

Lol. What's even scarier, you and I seem to be the only two that know that.

I have driven and owned a bunch of gm vehicles that came with the 7004r
The shifter was labeled. P/R/N/D/2/1 Many being 3rd gen f bodies
The 7004r jumps out of o/d with any type of throttle input stock , anything more than 1/4 throttle and it drop down to 3rd. You had to rework the transmission to floor it and keep it in 4th gear.
Anyone that has tried to do a high speed highway dash , with a vehicle with the 7004r knows this.

[MikeB]

Originally Posted by ChevyRacefan

I have driven and owned a bunch of gm vehicles that came with the 7004r
The shifter was labeled. P/R/N/D/2/1

P/R/N/D/2/1 is what you'd see with a TH350 and other 3-speed autos. Unless on some vehicles with the 700R4, GM didn't want to driver to be able to select between OD and 3rd. But there are 4 forward detents on the selector shaft, so I don't know how that would work.???

On the cars and trucks with the 700R4 that I've seen, there are 4 forward gears shown on the shift indicator: OD/D/2/1.



BTW, this is what I was referring to as the selector shaft, aka shift shaft. This trans may nor be a 700R4, but you get the idea.

[jimijam00]

Originally Posted by ChevyRacefan

I have driven and owned a bunch of gm vehicles that came with the 7004r
The shifter was labeled. P/R/N/D/2/1

If you mean "came with" as in from the factory, this is NOT possible.

[57taskforce]

The couple of 700r’s I’ve had I always shifted to OD above 50-55. If not, in stock form your not likely to get very long from them. ( although your Not likely to get very long from them to begin with if you use your truck as a truck in my opinion)

[Sheepdip]

Originally Posted by 57taskforce

The couple of 700r’s I’ve had I always shifted to OD above 50-55. If not, in stock form your not likely to get very long from them. ( although your Not likely to get very long from them to begin with if you use your truck as a truck in my opinion)

Another plus to the GV is it has a Auto and Manual (choice) position behind an automatic transmission, a manual transmission is engaged manually (clutch disengaged) simply because the hard hit it takes, where as an auto transmissions torque converter absorbs the shock.

At lower town speeds manual or off is the choice and when you are doing highway speeds it will auto kick in about 40 mph or you can kick it in manually if you choose at or above 40 mph.

The way the GV works, is at 40 plus mph it will engage via the signal from the speed generator, not before. The hydraulic pump pressure must be correct.
Once engaged it will stay engaged down to about 20 mph until the speed generator signal says no more via the controller.
As long as you stay above 20 mph you can select lower gears and make use of the .78 O.D.

This is why GV markets it as a Under/Overdrive and are extremely popular.

[richards72chevy]

My coworker worker had a bone stock 86 silverado with a 305/700r4 in it.Had no problems drove it daily to work and all over on the weekends for about the last 5 years.He said he thinks he put over 100,000 miles on it in them 5 years with no real problems.He decided to put in a 350 engine from ATK.He is on his third transmission in less than a year.

[Richard]

Originally Posted by richards72chevy

My coworker worker had a bone stock 86 silverado with a 305/700r4 in it.Had no problems drove it daily to work and all over on the weekends for about the last 5 years.He said he thinks he put over 100,000 miles on it in them 5 years with no real problems.He decided to put in a 350 engine from ATK.He is on his third transmission in less than a year.

I would guess that whomever changed the engine and is changing the transmissions is not adjusting the TV cable correctly. Also finding a reliable transmission rebuilder is really hard. They either skimp on bushings bearings and seals or do not do a good job.

[MikeB]

Originally Posted by Richard

I would guess that whomever changed the engine and is changing the transmissions is not adjusting the TV cable correctly. Also finding a reliable transmission rebuilder is really hard. They either skimp on bushings bearings and seals or do not do a good job.

Pretty sad, huh? My buddy with the 37 Chevy paid around $900 for a rebuilt 700R4 including converter. It's probably totally stock with standard rebuilder parts. I set up the TV cable, but I have to wonder how long the internals will last behind a 350 with probably >350 hp. It's been working OK for 2-3 years now, but I doubt it has 2,000 miles on it.

[richards72chevy]

Originally Posted by Richard

I would guess that whomever changed the engine and is changing the transmissions is not adjusting the TV cable correctly. Also finding a reliable transmission rebuilder is really hard. They either skimp on bushings bearings and seals or do not do a good job.

First one was rebuilt at a shop he took it in several times after they rebuilt it and they never got it to shift correctly.The second one was a monster transmission that was actually rebuilt by moveras that sells them to monster transmission then monster marks up the price.He installed the transmission then paid a mechanic to come over and adjust the tv cable.It would never shift past second gear and puked atf every where.The third one is coming from monster again after he paid lawyer to talk to them.They claim this one is being rebuilt at their shop in Florida where they are supposed to be.My project 66 has a 700 r4 in it unfortunately.My 72 has a turbo 350 that will never leave unless it's being rebuilt and put back in.

['68OrangeSunshine]

I think I'm permanently talked out of a 700-R4.

[Accelo]

To make it clear this discussion is about a transmission that hasn't been built since 1992, or 29 years ago. I agree they had issues. However a lot has been changed since then.
One could build a 700r4 (What GM has called a 4L60 for decades now) using updated parts from a modern 4L60E transmission. Also note that a lot of the issues with, lock up hunting, were installed in vehicles with high differential ratios. Typically not an issue with the vintage trucks were are dealing with on this forum. I still think they make great transmissions for retrofitting to our old trucks. You can and add a forth gear lock up switch, in series, to the control wiring if it bothers you. I have had several conversions and it was a simple as putting it in drive and go. I never had to worry about leaving it in drive and forgetting to shift to OD. If you are using the 1987 through 1992 transmission you should have no issues if the transmission if it was built correctly.
Rick

[leddzepp]

Good thread with lots of info and options

[BigBird05]

Anybody in South or North Carolina that doesn't like there 700r4 can give it to me. I'll come and pick it up.

[68is4me]

It all depends on what you want and what you are going to do with it. Either way is good. If you already have a good working th350 then why not go with GV. That would probably be the the fastest way to add OD. Another option is just change the gear ratio if is just a cruiser and not wanting to spend much.

Now as the 700r4 goes, I have one that is well built behind a big block, and I like it. But spent some money on it too. From billet shafts, billet t/q, changed 1st gear ratio, and built it to the 4l65 specs.

[MikeB]

HO455 -- I'm now wondering if a TH350C would be an inexpensive alternative to a OD trans or GV unit. My 69 C10 with TH350 slips around 200-300 RPM on the highway (depending on engine load) with a Hughes GM11TOW converter.

It would give me the equivalent of a .80 -.90 OD, meaning a 3.08 axle would effectively become 2.46-2.77. I'd probably only engage it above 65 mph.

Gotta do some research on this!

*** Just spoke with a guy at Phoenix Transmissions. They have 4 different TH350s to choose from and they can build any of them as a C model. Even their entry level trans is a step up from stock. That one would work great, because the truck has been running a stock one, except for a TransGo kit, for 30+ years, with nothing but fluid/filter changes and new seals.

The lock-up converter stall speeds are 1600 to 3500. I could probably be all-in for less than $2K and not have to relocate the crossmember or shorten the driveshaft. And my 3.08 axle will work just fine.