700R4 or 4L60?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
6,970
Reaction score
12,220
Location
Auburn, Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
You must be registered for see images attach

mind you the fluid you saw was fresh fluid by like a couple weeks before that at most, and the filter/ and pan were clean and fresh

The dark tint of the fluid is wear stuffs from excess what you see here I think, and then the "uh oh" part you may think is water or coolant, but its just air. it was overfilled and the fluid was getting smacked like a battered woman with an abusive husband whos pissy kinda smacked
I also used the cooler lines to drain the transmission a little more than just pull off and let it drain, I ran the engine short bursts after the pan stuffs all stopped because I wanted to get anything that would come out with it

like the bits of metal and the contents of that bucket lol... also used the transmission to pump out the cooler both ways, spit out some $$ things too
Relevance to the topic?
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,755
Reaction score
11,402
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
Upon further inspection, I find the PO lied and I have a 305 c.i. engine with a 203 transfer case in my 1984 K10. The original 700R4 is toast and no remanufacturer or rebuilder will take it as a core. now, I am told that the newer the transmission I buy, the better. The recommendation is to buy a '90 or '91 4L60 (not the later 4L60E which is computer controlled) as a direct replacement. I have been told it is a plug & play exact replacement. What say you experts????
As always, your sage advice is greatly appreciated!
I'm not going to be of as much help to you as I'd like to be but I'd like to say this.

I bought my truck from the widow of a deceased friend. As long as I knew the man that previously owned it he always said it had a 350. Not to long after I got the truck I needed to replace the oil pressure sending unit, and while I was back there I took a look at the block numbers. Not surprisingly it's got the 305. They are such similar engines on the outside, the PO of your truck just might not have known. And honestly I think the 305 gets an undeserved bad rap. I have worked the heck out of my 305 / 700R4 combo. Sure it's slower than a 350 when I have the truck loaded down or I'm towing my big trailer but it always gets the job done. If you think back to the 60's lots of medium duty trucks had straight 6's. So from that prospective I'm fine with the 305, I would like to change the gears to make better use of what the 305 provides.

As for the 700R4, I agree with what other folks have said a local tranny shop is best if you can find one with an old guy that knows these trannys, even better if you can find a shop that someone else has had a 700R4 done at. The only online place I'd even consider buying a tranny from is bowtie overdrives. I have no personal experience with them, but it is all they do. My plan when my tranny needs to be rebuilt is to either take it to a tranny shop 2 hours away that someone on this forum has had work done at. My back up plan if for some reason I can't make the trip would be bowtie, but they sure are spendy! You didn't ask about this but a trans cooler and gauge will help protect your investment. I personally would not do the 4L60 because I do not want electronics to deal with, but that's just me. I'd end up going to the TH400 before I did the 4L60, again don't take this as advice per-say it's just my plan when the time comes and I thought you might find something in there useful.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,451
Reaction score
3,819
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
You must be registered for see images attach

yum
That’s most likely converter failure. There is a bunch of aluminum glitter in the fluid. Other than the transmission pump, there isn’t much aluminum that can wear on a 700 other than the aluminum parts inside the converter.

Definitely clean/flush the cooler on that one. When you think it’s clean enough, clean it again!!
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,451
Reaction score
3,819
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
I'm not going to be of as much help to you as I'd like to be but I'd like to say this.

I bought my truck from the widow of a deceased friend. As long as I knew the man that previously owned it he always said it had a 350. Not to long after I got the truck I needed to replace the oil pressure sending unit, and while I was back there I took a look at the block numbers. Not surprisingly it's got the 305. They are such similar engines on the outside, the PO of your truck just might not have known. And honestly I think the 305 gets an undeserved bad rap. I have worked the heck out of my 305 / 700R4 combo. Sure it's slower than a 350 when I have the truck loaded down or I'm towing my big trailer but it always gets the job done. If you think back to the 60's lots of medium duty trucks had straight 6's. So from that prospective I'm fine with the 305, I would like to change the gears to make better use of what the 305 provides.

As for the 700R4, I agree with what other folks have said a local tranny shop is best if you can find one with an old guy that knows these trannys, even better if you can find a shop that someone else has had a 700R4 done at. The only online place I'd even consider buying a tranny from is bowtie overdrives. I have no personal experience with them, but it is all they do. My plan when my tranny needs to be rebuilt is to either take it to a tranny shop 2 hours away that someone on this forum has had work done at. My back up plan if for some reason I can't make the trip would be bowtie, but they sure are spendy! You didn't ask about this but a trans cooler and gauge will help protect your investment. I personally would not do the 4L60 because I do not want electronics to deal with, but that's just me. I'd end up going to the TH400 before I did the 4L60, again don't take this as advice per-say it's just my plan when the time comes and I thought you might find something in there useful.


If you expect transmission problems in the future, start planning ahead. That will minimize the headaches and downtime.

Find a later 700 with the St. Louis shaped casting line on the passenger side. Those have all the hood factory upgrades. Have that built, and either install it or have the shop do the installation.

You have the benefit of time. The truck still drives, you can be ready if/when problems do occur.

And btw, the 700 and 4L60 are the same trans, just different names. Just like the old 400 was renamed the 3L80 in the later years. The 4L60E is basically the same trans as a 700/4L60, just with an electronic valve body. Most of the internal parts are interchangeable with the exception of the case, pump and valve body.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,755
Reaction score
11,402
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
If you expect transmission problems in the future, start planning ahead. That will minimize the headaches and downtime.

Find a later 700 with the St. Louis shaped casting line on the passenger side. Those have all the hood factory upgrades. Have that built, and either install it or have the shop do the installation.

You have the benefit of time. The truck still drives, you can be ready if/when problems do occur.

And btw, the 700 and 4L60 are the same trans, just different names. Just like the old 400 was renamed the 3L80 in the later years. The 4L60E is basically the same trans as a 700/4L60, just with an electronic valve body. Most of the internal parts are interchangeable with the exception of the case, pump and valve body.
First of all I refer to you for all transmission issues... I seriously trust this guys knowledge.

I've never thought to look at the casting when I have been under the truck, I have no idea if the trans I'm running is the OE 1984, if it has or hasn't been rebuilt and what if any upgrades it's had. What I do know is that it's old, and I use the truck for a lot of towing and hauling. Of course I added a cooler and gauge. I do NOT have trouble with getting hot. Even still it does have some shifting funk, 2 - 3rd shift likes to be late while all others are where they should be. And when slowing down it seems to like to stay in overdrive longer than it should. It's nothing that I can't manage, and there is no slippage at all. But still I figure one of these days sooner or later it's gonna need to be rebuilt. I'm not planning to have one rebuilt ahead of time and sitting on the floor waiting, but I do have a plan for when that comes.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,451
Reaction score
3,819
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
First of all I refer to you for all transmission issues... I seriously trust this guys knowledge.

I've never thought to look at the casting when I have been under the truck, I have no idea if the trans I'm running is the OE 1984, if it has or hasn't been rebuilt and what if any upgrades it's had. What I do know is that it's old, and I use the truck for a lot of towing and hauling. Of course I added a cooler and gauge. I do NOT have trouble with getting hot. Even still it does have some shifting funk, 2 - 3rd shift likes to be late while all others are where they should be. And when slowing down it seems to like to stay in overdrive longer than it should. It's nothing that I can't manage, and there is no slippage at all. But still I figure one of these days sooner or later it's gonna need to be rebuilt. I'm not planning to have one rebuilt ahead of time and sitting on the floor waiting, but I do have a plan for when that comes.
Nonsense!!! Spending the money to have the trans ready is the best possible way to ensure you NEVER need it!!

About 10 years ago, my son had a school project that required him to document and describe any process he wanted. He wanted to take apart the engine in my car, take pictures, and reassemble it. Needless to say, I wasn’t very enthusiastic about that, but I compromised.

Many years ago, I bought a rusted out 68 Toronado. The story I got was the owner bought it new to deliver mail in northern Michigan, hence the dreaded “tin worm” infestation. The car had 68000 miles and ran excellent, but was so rusted the doors wouldn’t open/close right. I bought the car specifically for the engine, the fact that it was cheap and low mileage made the deal even better.

That was the engine we used for his project. Did a basic re-ring/bearing/few hours fast upgrades, he got an A on his project, I have a backup engine for my car.


The engine is filled with fogging oil, wrapped in plastic, ready to go. If I didn’t have a engine ready to go I would have blown up the engine in my car. Cheap insurance!!
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,693
Reaction score
6,869
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
That’s most likely converter failure. There is a bunch of aluminum glitter in the fluid. Other than the transmission pump, there isn’t much aluminum that can wear on a 700 other than the aluminum parts inside the converter.

Definitely clean/flush the cooler on that one. When you think it’s clean enough, clean it again!!
that was my 4t65e lol just showing my milkshake
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,693
Reaction score
6,869
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
If you expect transmission problems in the future, start planning ahead. That will minimize the headaches and downtime.

Find a later 700 with the St. Louis shaped casting line on the passenger side. Those have all the hood factory upgrades. Have that built, and either install it or have the shop do the installation.

You have the benefit of time. The truck still drives, you can be ready if/when problems do occur.

And btw, the 700 and 4L60 are the same trans, just different names. Just like the old 400 was renamed the 3L80 in the later years. The 4L60E is basically the same trans as a 700/4L60, just with an electronic valve body. Most of the internal parts are interchangeable with the exception of the case, pump and valve body.
do those adapt decent to BOP or is it work? I was thinking about future transmissions and thought about a new production 4 speed from GM forgot the name but its a 4t60e case with different..? design to it, anyway, made to be "drop ins" with simple wiring and junk. But a 700r4 wouldnt be very helpful in a buick or pontiac engine car.. lol.. like, to avoid needing to get with the times but also get with the 80s and 4 speeds.
 

Latest posts

Forum statistics

Threads
44,163
Posts
950,653
Members
36,276
Latest member
2manysquares2care
Top