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.

[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

[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.

[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...

[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)

[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.