700R4 Conversion FAQ

[Project1970]

I suppose it's about time someone wrote one. Feel free to contribute.

Which one to get?
The 700R4 was produced from 1982 until 1992. It was renamed the 4L60 for 1993, and I believe it's otherwise identical. 1994 brought the 4L60E, which requires a computer to run. The good years to get are any made in 1987 or later. Try to find a unit that has a mechanical speedometer as well, but if not, it's not a big deal to change one over. The 1987 and later units have quite a few improvements that do a lot for helping the 700's longevity.

If you're getting a rebuilt one, it's no different than any other kind of transmission - get it from a reputable shop. Ideally, the original core would be an '87 or later, but an older one with updated internals should work just as well.

Other Things Needed For Swap:
*Transmission cooler
*Cooler lines if there wasn't an auto in previously, or if the old ones are in bad shape
*TV (throttle valve) cable and a bracket to mount it - go to a dealer for these. P/N 25515598 Throttle valve cable @ $20.00 and Bracket P/N 22504927 @ $17.00 (GM) . Bracket has oppenings for accelerator cable and for the T.V. cable and bolts to back two bolts on Quadrajet.
*Speedometer cable - the one from my THM400 was just a few inches too short. Yours may work, but don't be surprised if it doesn't, the 700R4 is a long tranny.
*Automatic crossmember, shifter, and linkage if there wasn't an auto in previously
*New or modified driveshaft (chances are it will need to be cut and put a new yoke on it)
*Grade 8 hardware to bolt the crossmember in
*Metric bolts to attatch the torque converter to the flexplate - at least mine uses them, but given that the Chevy parts counter gave me SAE the first two times, my guess is not all 700's use them.
*Speedometer drive and driven gears, and possibly the sleeve, depending on the transmission and gearing/tire setup. There are two sleeves, depending on the size of the driven gear. Get the sleeve at a junkyard if you can; I didn't have the option of waiting and had to pay almost $60 for it over the GM parts counter!
*Patience

Tips for the swap:
For the most part, the 700R4 is a fairly straightforward install. There's nothing really special about the physical installation of the transmission; just drop the old one, put the new one in, bolt it all up, and drill holes for / bolt the crossmember in. Don't forget to mount the transmission cooler too! Call your driveshaft shop, measure the distance they want, and have yours modified to fit. (Now's a great time to go with a one-piece!)

The "tricky" parts, though, are the TV linkage and the TCC (torque converter clutch, aka lockup) wiring. I'm not even going to try to explain the TV linkage; this site does a GREAT job of explaining the details of it. It's also quite possible to "get it close" by just retracting the cable (it makes sense once you look at a cable, the end 'ratchets') and then moving the throttle hard to WOT (engine off, of course!), and then take it immediately to a transmission shop to have it adjusted. I set mine using the method in the page and it's working perfectly.

TCC wiring is much easier than it seems. The only problems occur mainly because GM used mutliple wiring setups inside. I'll describe my setup:
I want it to only have torque converter lockup in fourth gear. I also want it to disengage under braking, and under heavy throttle, so it doesn't kick down with the converter locked. So, first, I ran an ignition-hot 12V wire to a new brake switch for a later-model Chevy truck. You want a switch that has two sets of contacts - one that is connected when the brakes are off, and one that is connected when the brakes are applied. The latter will be connected to your brake lights, the former will be connected to the new 12V ignition-hot wire. From this switch, I ran a wire to the engine compartment, where I mounted an engine vacuum switch - simply, it's closed under high vacuum (low throttle), but opens up as vacuum drops (high throttle). This can be omitted if your engine doesn't make enough vacuum to keep it closed. From here, the wire goes down to the transmission's "A" pin on the connector. Inside the transmission, as far as the TCC goes, you have two things - a fourth-gear switch and the solenoid itself. Mine has a dual-wire solenoid and a single-wire, closed-with-pressure fourth gear switch. The 12V from the A-pin goes to one wire of the solenoid, and the other wire goes to the single-wire switch. When the transmission shifts to fourth gear, the switch completes the ground for the solenoid. If all other switches are closed (no brakes, low throttle) and all connections are good, the torque converter will then lock.

The variations here come from the fact that there were both one-wire and two-wire solenoids, one-wire and two-wire switches, and both closed-with-pressure and open-with-pressure switches. I'll start off by saying the open-with-pressure switches will only work with a relay; they're set up for computer-controlled cars. Make sure you have a closed-with-pressure 4th gear switch.
There are two other combinations other than mine that should work:
*A-pin to two wire switch to single wire solenoid
*A-pin to two wire switch to two wire solenoid to D-pin to ground.

If you're confused, and I don't blame you, think of it this way: You want 12V to the TCC solenoid when you want the converter locked, and to unlock it, remove the 12V. Use the switches / connections you have to do so. Also, if you have a single-wire solenoid, you can -only- control the 12V side.

Other notes:
Last thing I can think of is that I've read that sometimes a fresh 700R4 has difficulty hitting fourth gear; mine did. The solution sounds slightly scary, but it worked for me: jack the rear of the truck up, pull the wheels and drums, DON'T HIT THE BRAKES, make sure the truck is EXTREMELY secure, and wind it out to at least 100 on the speedo. Basically, an Italian tuneup, standing still. I make no warranties on that information, and it is rather dangerous in my opinion, but it does beat the alternative of winding it out to 100+ on the road.

[Project1970]

Good Links:

http://www.sallee-chevrolet.com/Chev...tallation.html
This isn't 100% relevant, but it does contain a lot of good info, and part numbers to boot. It would appear that one of the differences of the 4L60 and the 700R4 is that the 4L60 has a 5-pin connector instead of the 700R4's 4-pin. This page also shows the 4L60/700R4 "Extension Housing" that puts it in the same place as a TH400; this isn't needed if you don't mind moving a crossmember, just see the link below.

http://www.highperformancecars.com/crosley/700id.htm
This one has a lot of great photos and other good info, such as a more detailed version of how to covnert a 700R4 from electronic to mechanical speedo, some more lockup wiring info, and some year-identifying info.

http://www.73-87.com/garage/speedo.htm
The '73-'87 guys have a great site regarding the speedometer gears, including part numbers and combos for rears/tire sizes.

[Cap'n Hook]

Don't forget a good tranny mount for that cross member!!

[CustomChevy]

additional info here:


www.700r4.com

[73stepside]

4l60 was named in 92 and switched to 4l60e in 93. 84 and later had the 30 spline input shafts. the switch over to the speed sensor in cars was 84-85. in trucks it was about 87-88 time line.

[Ochre]

Originally Posted by 73stepside

4l60 was named in 92 and switched to 4l60e in 93. 84 and later had the 30 spline input shafts. the switch over to the speed sensor in cars was 84-85. in trucks it was about 87-88 time line.

www.jagsthatrun.com sells adapters for converting from mech --> elec (for EFI applications) and elec-->mech (for using a mech speedo on an electronic sensor)

[blazzeslang]

www.bowtieoverdrives.com is a great informative site on the transmission and swap procedures

[Tim240Z]

What are you guys using for a shifter with the overdrive conversion. Obviously the original column shifter is only 1-2-3-n-r-p, so one more detent is needed (unless you are willing to lose 1st gear selection). Is there an oem/junk yard solution for column change/conversion?
I pulled a 200 4R from the junkyard and installed it using the stock column linkage on my 71 Cheyenne 20, but lost 1st gear selection. The change was very easy apart from the shifter issue. I ended up pulling the tranny out and putting the TH350 back in because the 200 needs a rebuild.
But after I rebuild it, what can I do for proper shifter selection?
(BTW, I did several searches and the only answer I could find was to use an aftermarket column/shifer...$$$$)

Thanks,
Tim

[72k5]

Originally Posted by Tim240Z

What are you guys using for a shifter with the overdrive conversion. Obviously the original column shifter is only 1-2-3-n-r-p, so one more detent is needed (unless you are willing to lose 1st gear selection). Is there an oem/junk yard solution for column change/conversion?
I pulled a 200 4R from the junkyard and installed it using the stock column linkage on my 71 Cheyenne 20, but lost 1st gear selection. The change was very easy apart from the shifter issue. I ended up pulling the tranny out and putting the TH350 back in because the 200 needs a rebuild.
But after I rebuild it, what can I do for proper shifter selection?
(BTW, I did several searches and the only answer I could find was to use an aftermarket column/shifer...$$$$)

Thanks,
Tim

The detents you feel when you move the shift lever come from inside the tranny, not in the column, etc. So the problem is in rotating the tranny selector shaft enough degrees to be able to reach all the positions. You may be able to do this by adjusting the linkage. Mine has an adjustment bolt up by the brake booster. If that won't do it, or you don't like the fact that 1st is now off the scale, like I didn't, here's what to do:

Take the linkage off of the selector shaft crank (next to the tranny). Put the trans in first, and have someone hold the shifter lever where you want it to be when in first. Hold the linkage up to the crank, and find the position along the crank where it should be if there was a hole there. Mark that spot. Put the trans and the shifter lever in park and make sure that you can adjust the linkage so that it would work with the hole in the position you marked. If you have to readjust the linkage, check it again in first. You should be able to figure out where to put the hole with one or two attempts. The new hole will probably be about 3/4 inch closer to the selector shaft than the original.

I worked mine out on graph paper by measuring the stroke of the linkage, then comparing it to the available radius choices from the length of the crank and the amount of rotation needed. That's an alternative if you're more comfortable with that, but after I did it I found it really didn't need to be that precise.

For the column with the indicator perched on top of the column, you can replace the plastic in the indicator with a piece from "Ididit" that will properly indicate the added gear positions. I had to sand it down a touch to fit, and nighttime illumination is not as good as the original, but it is great for giving proper gear identification.

You wouldn't know from operation or look that the setup I have isn't OE (except for the dim indicator at night), so I can't see any advantage to a replacement column.

[passthebuck]

I used this kit (I'm not advertising for Jegs, its just the first one i found):

http://www.jegs.com/cgi-bin/ncommerc...22&prmenbr=361


& it works great for me. its got the right solenoid & the right pressure switch. i installed it back in 95 & its still a quality piece.

[pjmoreland]

The speedometer gear webpage listed above has moved:

http://www.73-87.com/7387garage/drivetrain/speedo.htm

I suggest using the formula listed in the link instead of going off the table. I found that the value in the table that corresponded to my setup was incorrect.

For my SWB 2WD truck with the engine in the forward position, and with stock suspension, the driveshaft length ended up being 56 1/4" long measured from u-joint to u-joint.

The stock GM vacuum switch for controlling the TCC is part number 14032087, and the vacuum delay valve that goes in between the vacuum switch and the vacuum source is part number 14020691.

[cwilkie]

Does Bracket P/N 22504927 which has the oppenings for accelerator cable and for the T.V. cable and bolts to back two bolts on Quadrajet work with a big block?

Chance

[hoser]

Great thread.

I installed a 700R4 and transfer case out of a 86 Suburban into my 72 GMC now the spedo cable is too short anybody know where I can get a longer cable assembly or an extension?

Thanks.

[72MARIO]

The Lokar universal shift linkage works great that will allow you to get all the grear on the coloum. You will need the long verson of the kit. It's avaible from Summitt Racing or your local speed shop.

[hoser]

Originally Posted by 72MARIO

The Lokar universal shift linkage works great that will allow you to get all the grear on the coloum. You will need the long verson of the kit. It's avaible from Summitt Racing or your local speed shop.

Thanks for the reply but I am not sure I follow what your sayig, using the stock linkage I get all the gears I dont have the OD mark on the pointer but who cares I just put it in drive and the trans shifts all the way up into OD

[72MARIO]

Well I was not relplying to you. Just as added info to this thread Tim240Z was asking the question.


hoser, The cable I am using is from a 71C20 with a T350 tranny. That works with my 2WD.

I would try a 70's 4x4 with a T350 tranny. If not lokar makes a universal cut to length cable avaible thru summit also.

[hoser]

Originally Posted by 72MARIO

Well I was not relplying to you. Just as added info to this thread Tim240Z was asking the question.


hoser, The cable I am using is from a 71C20 with a T350 tranny. That works with my 2WD.

I would try a 70's 4x4 with a T350 tranny. If not lokar makes a universal cut to length cable avaible thru summit also.

oops sorry heh

The current cable I have that is too short is a 72 GMC 4x4 cable th eold trans was the TH350, guess I will have to get a universal cut to length cable thing.

Thanks again.

[Already Gone]

I want to do this swap and bought a complete wrecked 90 Suburban 4x2 with the 700R4 and mechanical speedo. My truck is a 72 Long Box with a 396 and TH400. Will this be an easy swap to do? Why do you need transmission cooler ? I dont have one on the TH400. Do the 700's run hotter.?

I dont race the truck but love blowing away rice rockets when the circumstances are right like at 06:30 in the AM when I'm on my way home from work and some ricer pulls into the inside lane at a light expecting to get in front of me when the light changes. I have the 396 badges on my fenders but I'm sure alot of these younger guys driving rice rockets dont know what the 396 means.

[Tx Firefighter]

Originally Posted by Already Gone

I want to do this swap and bought a complete wrecked 90 Suburban 4x2 with the 700R4 and mechanical speedo. My truck is a 72 Long Box with a 396 and TH400. Will this be an easy swap to do? Why do you need transmission cooler ? I dont have one on the TH400. Do the 700's run hotter.?.

If you already have a TH400 auto trans, you have a cooler. Just screw the two lines into the 700 just like they came out of the TH400.

Two side notes...

Vans used mechanical speedos much later than trucks. I've gotten them from early 90's vintage with cable speedos still

Second point. If you have a short bed V8 truck, all you need is a driveshaft out of any later model short bed auto trans truck. GM went to the 9 inch tail TH350 in the 70's, and it's exactly the same length as a 700R4 is, and the short bed trucks had the same wheelbase and engine setment as the earlier trucks did. Every time I do a 700 swap, I just get a boneyard short bed auto driveshaft from any 80' or 90' truck. I've used them from mid 80's and my latest one is from a 92 model. If memory serves me, they are 56 inches long. I can measure the one I have in my shop right now if need be.