Need Some 700r4 Advice QUICK!!!

[Ole Blue 68]

I'm looking to switch out my 3 spd manual for a 700r4 to get the ease of an automatic and also improve mpgs. I'm supposed to go look at a used TCI trans tonight but when I pulled the part number, it's saying its a non-lockup unit. What do you guys think? Worth it or not? This is for a mild street truck.

Here's a link...http://www.compperformancegroupstore..._Code=700TRANS

[mnunn454]

I think you'll gain 2-3% on your highway MPG if you'll opt for a 700R4 with lockup. Over time it'll pay for the difference in cost.

[Ole Blue 68]

Originally Posted by mnunn454

I think you'll gain 2-3% on your highway MPG if you'll opt for a 700R4 with lockup. Over time it'll pay for the difference in cost.

Yeah, the problem is I'm buying this one used (pretty good deal) so I can't really choose.

[racin69z]

It'll defineately get better than a th350 and if you plan on running a pretty high stall converter, I think high stalls are cheaper for non lockup converters.

[piecesparts]

I run a NON lock up 700R4 tranny in my truck and my son's truck. The lock up would give me some gain in mileage over the NON unit, but I am running stall converters in the trucks, due to the cam profiles. My trannys originally came from a company that was called Premier Performance, which was purchased by the JET Performance people. I purchased the trannys back in the 1996 time period and have since rebuilt my tranny in my truck and added the latest heavy duty goodies that is available on the market. I have a stroked 385 motor in my truck with about 420 HP and a 3.73 gear ratio. I also run a lower profile tire, which will adjust the gear ratio to around a 3.80 number over the standard truck tire. I get great acceleration and average 15 MPG on my truck with the engine turnig 2500 RPM at 70 MPH. I used to have a 3.42 geared rear end and the RPMs were about 150 RPMs lower and th emileage was around 16 MPG.

My daily driver (a 91 Chevy Silverado with a 700 R4 WITH a lock up converter and a 3.42 gear ratio) gets around 20 MPG, but I have done some changes on themotor to help. The TBI fuel injection is the first part of this, along with an electric fan set and open air intake and dual exhaust. When I purchased the 91, it was getting around 16.5 MPG and I have helped it a lot.

[shortbus2]

With a non-lockup I don't think it would be worth it. If you want better gas mileage get a standard 700, the lockup clutch in the converter gets rid of alot of heat(because the converter isn't slipping) and would prolly be better for the road.

[cdowns]

i used a non locking 2004r for many years with no issues and got great gas mileage if you're sure the tranny hasnt been abused and the price is good buy it

[Vince M]

The installation will be easier with the non-lockup. (No wiring). 99% of 3 speed auto's are nonlockups but it is true that the tranny will run cooler with a lockup. Heat kills an automatic. You might be able to compensate for this by putting in a good cooler. (you'll need one anyways).
Some other things to note;
You'll need a TV cable mount at the carb and the correct stud on the carb to attach it to.(in the correct location)
You'll need a flex plate with the proper bolt pattern. Most new flexplates come with the dual bolt pattern to fit old and new torque converters.
You'll need a longer driveshaft.
You'll need an auto tranny cross member. (Good luck removing the old crossmember and rivets!)
I purchased a new tailhousing that has the integral tranny mount in it. It puts the tanny mount in the same location as a TH400. This makes it easier to install and gives you much needed clearance for the pan.
If you've got a column shifter, a new steering column or a floor mounted shifter will be required and all the linkage.
These are just a few things I had troubles with. I found the installation of the tranny the easiest, it was all the other stuff that took more time. Hope this helps.

[Ole Blue 68]

Thanks for the info guys.

Well I went ahead and bought it...no turning back now. USED TCI Streetfighter Trans and TCI torque converter w/ about 8,000 miles on it plus a used stock converter off of a 92 truck for $750. I met up with the dude about half way between where we lived so there wasn't much I could do to check it out. Splines looked good and the fluid looked fine and I thought that was a pretty dang good price so I went for it.

And thanks for the list Vince M, that's what I gotta start working on next....

[mnunn454]

Congratulations.

Two things you can consider with your new tranny:

Use an external tranny fluid cooler and bone up on how to correctly adjust that Throttle Valve (TV) cable. Doing both of these will help protect and lengthen the life of your new investment.

[Ole Blue 68]

Originally Posted by mnunn454

Congratulations.

Two things you can consider with your new tranny:

Use an external tranny fluid cooler and bone up on how to correctly adjust that Throttle Valve (TV) cable. Doing both of these will help protect and lengthen the life of your new investment.

Thanks man, believe me I wouldn't consider running this trans without a cooler. Does anybody know if all of our radiators were plumbed for a trans cooler? I think I read that somewhere here on the board. If so, that would cut down on the cost as well...

[greasy68]

My radiator is plumbed for a trans cooler and I think most are. It has two ports on the passenger side about half way down the side. I ran hard lines which can be a pain but it is cheap insurance. I love my 700r4. I have the lockup version but I can't imagine there is a huge difference unless you are planning cross country trips.

[Ole Blue 68]

Originally Posted by greasy68

My radiator is plumbed for a trans cooler and I think most are. It has two ports on the passenger side about half way down the side. I ran hard lines which can be a pain but it is cheap insurance. I love my 700r4. I have the lockup version but I can't imagine there is a huge difference unless you are planning cross country trips.

Thanks Greasy, I wasn't sure if they were plumbed on the side or on the bottom. Now I gotta a starting point to check this weekend. I found this site that has some pretty good prices, including a Hayden unit along with the mount and plumbing kit for $45.

[Mister laugh]

Originally Posted by Ole Blue 68

Thanks man, believe me I wouldn't consider running this trans without a cooler. Does anybody know if all of our radiators were plumbed for a trans cooler? I think I read that somewhere here on the board. If so, that would cut down on the cost as well...

Not to offend you, but you just spent $750 on a transmission, you are much better off going out and spending %80 bucks on the BIGGEST transmission cooler you can find, it's cheap insurance. In my experience the transmission coolers built into vehicles are rarely big enough.

[Ole Blue 68]

Originally Posted by Mister laugh

Not to offend you, but you just spent $750 on a transmission, you are much better off going out and spending %80 bucks on the BIGGEST transmission cooler you can find, it's cheap insurance. In my experience the transmission coolers built into vehicles are rarely big enough.

No offense taken. By plumbing, I meant the holes to run cooler lines through the radiator to an external cooler. (I've got a 3 spd manual so right now, there's no trans cooler at all)