[warpdriv]

So I got to thinking about sources of 700R4s. Just for grins, I called up O'Rilleys and had them look up one for a 88 K2500 (Chevy) 4x4 (because my project is going to be a FJ60 land cruiser) with a 6.2 diesel. He quoted me $1479 plus $400 core 3yr 75k mile warranty.

The only question I have, which he did not know, is how the governor (I think that is the term) is setup to build up high line pressure at low RPMs. The 6.2 was rated 257lbs of torque at 2k rpm. From searching the 4bt reaches max torque at 1700rpm.

Do y'all think a tranny built for a 6.2 can properly handle at 4bta?

Thanks,

 

[averagef250]

I don't think the 700R4 was built to handle the 6.2. The governor works with centrifugal flyweights under a cover on the side of the tranny. By changing the weight of the flyweights you can alter shift points.

 

[Machman]

Can the 700R4 handle the output of a 4BT? I think the answer on that is yes, if properly built incorporating all the updates over the years, and mebby some of the "upgrades" from the aftermarket, depending on how far you want to twist the screws on the 4BT.

Mating the two isn't the major problem, though you'll need to adapt the torque converter via some method.

The REAL challenge appears to be getting it to work right. Shifting problems seem to be where folks that have tried this encounter difficulties. Most of it can probably be attributed to problems getting the Throttle Valve cable right, and then the governor needs to be modified to represent the RPM band of the 4BT. The one used for the 6.2 / 700R4 combo will NOT be correct.

Not saying it can't be done, in fact I've had a few ideas about how to address the TV issue, but I don't wonder if it'd not be easier to go the 47RH route if you want a non-computer controlled overdrive automatic. If you're looking to save money and use a 700R4 because you have one already, I can understand that. But reading about the problems folks are having trying to get it working right, I have to think that a different route is better in the long run.

 

[DarylB]

If finances permit this January, I'm going to attempt to get the tranny built and the Scrambler driveable. Bill said he'd work with me (The transmission guy, who customed the converter) on proper adjustment. I'll be sure to keep everyone updated.


*edit*

$400 for a tranny core is outrageous. Bill quoted me $40-50 for a K-case core charge here. His basic price for a standard 700R4 is $795. When you add all the good clutches, 13 vane pump, corvette servo, etc, etc you're looking at about $1200. The 4x4 short (NP205) shaft runs about $160-180. I've estimated my costs to be about $1400 in the tranny rebuilt & installed + the $300 on the converter.

 

[B1jetmech]

The fix is in...constant pressure valva body

TCI has introduced a constant pressure valve body which will eliminate transmission burn up forever.

GM designed the 700R4 to rely too much on TV cable adjustment for proper pressure to operate the transmission properly.

To me, this is worth it's weight in gold. I'm making the investment so I will never have to worry about the tranny burning up due to a lack of of TV cable adjustment.

Check here: http://tciauto.com/Products/GM/gm_4L60E.asp

The 700R4 with modern updates and performance products can handle a 4BT with no problem. I'm confident with mine just make sure the it's built with the good stiff like sun shell, corvette servo, wide band, Z-pack clutches and a good torque converter. i would say these are the minimums.

So build it good, add the constant pressure valve body and good built torque converter and your good to go.

 

[Machman]

TCI has introduced a constant pressure valve body which will eliminate transmission burn up forever.

GM designed the 700R4 to rely too much on TV cable adjustment for proper pressure to operate the transmission properly.

To me, this is worth it's weight in gold. I'm making the investment so I will never have to worry about the tranny burning up due to a lack of of TV cable adjustment.

Check here: http://tciauto.com/Products/GM/gm_4L60E.asp

The 700R4 with modern updates and performance products can handle a 4BT with no problem. I'm confident with mine just make sure the it's built with the good stiff like sun shell, corvette servo, wide band, Z-pack clutches and a good torque converter. i would say these are the minimums.

So build it good, add the constant pressure valve body and good built torque converter and your good to go.

What are the shifts going to be like with that thing? IIRC, the greater the line pressure, the firmer the shifts are gonna be.

Firm shifts are GREAT for the track or when you're "hammer down" on the street. But I'd worry about living through the first one that happens when the GF is trying to put on makeup while we're just putting down the road.

 

[turbos10]

I would go with the constant line pressure upgrade as mentioned. You could also set it up full manual and you would not have to worry about shifts because it is in the palm of your hand. I just finished a 4L80 setup like that and I enjoy being able to make is shift like it should. Setting up a transmission that is primarily designed for gasoline to work right with a diesel is tough. I spent alot of time and some money on a TH400 behind a 6.5T and it finally shifted like it should have, but that was with the use of a vacuum regulator and alot of tweeking of the modulator and regulator.

 

[DarylB]

TCI has introduced a constant pressure valve body which will eliminate transmission burn up forever.

GM designed the 700R4 to rely too much on TV cable adjustment for proper pressure to operate the transmission properly.

To me, this is worth it's weight in gold. I'm making the investment so I will never have to worry about the tranny burning up due to a lack of of TV cable adjustment.

Check here: http://tciauto.com/Products/GM/gm_4L60E.asp

The 700R4 with modern updates and performance products can handle a 4BT with no problem. I'm confident with mine just make sure the it's built with the good stiff like sun shell, corvette servo, wide band, Z-pack clutches and a good torque converter. i would say these are the minimums.

So build it good, add the constant pressure valve body and good built torque converter and your good to go.

BobS/Andre

- can you sticky that link in the FAQ thread for the 700R4? - this is a good link.

 

[BobS]

BobS/Andre

- can you sticky that link in the FAQ thread for the 700R4? - this is a good link.

Done!

 

[B1jetmech]

What are the shifts going to be like with that thing? IIRC, the greater the line pressure, the firmer the shifts are gonna be.

I called TCI about this and they said the shifts would be harder because the 700R4 is operating at a minimum of 200 PSI line pressure.

My take is, there would be no need for a hard care shift kit. Shift hard is good but what the 700R4 needs more then anything is "Holding" pressure to prevent the clutches slipping from a lack of pressure. That's where this constant valve body comes into play.

 

[whiteman]

Would this eliminate the TV cable?? Or just how accurate we have to be when installing it?

 

[B1jetmech]

Would this eliminate the TV cable?? Or just how accurate we have to be when installing it?

It would not eliminate the TV cable, however the TV cable adjustment is not critical to 700R4 line pressure anymore. The TV cable can be disconnected and would only effect shift points but the tranny would be operating at a minimum of 200 psi line pressure and will not burn up.

 

[Floridan Surfer]

I know this is a old thread, however I just scored a k case on craigslist for $200 with only 10,000 miles on a rebuild. Other than this constant pressure valve body, is there any other upgrades I should do to It before installing? I've heard something about a 10 vane pump as opposed to the standard 7 vane pump. Any comments on this or any other suggestions?

 

[nexxussian]

I know this is a old thread, however I just scored a k case on craigslist for $200 with only 10,000 miles on a rebuild. Other than this constant pressure valve body, is there any other upgrades I should do to It before installing? I've heard something about a 10 vane pump as opposed to the standard 7 vane pump. Any comments on this or any other suggestions?

It kinda depends on how heavy a vehicle and how much power you intend to add.

There are people on this very forum with lighter vehicles (Land cruisers primarily IIRC) with stock or nearly stock power that are satisfied with theirs.

However I don't recall anything positive from those with heavy vehicles (suburban, heavy towing, lifts with large tires,...), those with the power turned up, those with a heavy or abusive foot, or any combination of these.


Heavier service requires more mods, at some point it's cheaper to get a 4L80E and stand alone controller than it is to beef up a 700R4 sufficiently, you have to decide where the break even point is.

 

[Floridan Surfer]

Mine is a 5500 pound Land Cruiser with 33 inch tires. I will will eventually upgrade to 35 – 37 inch tires. Occasional light wheeling and towing. The engine is stock 120 hp and will stay that way.

Are you implying that the constant pressure valve body is overkill? Should I just upgrade the pump and servo?

 

[eod1]

Hey guys I'm putting a 4bt in my 81 jeep cj8 and backing it with a 700r4 and np205. I'm thinking about the TCI constant pressure valve body. The 700r4 is getting the red clutch pack I think it has 11 clutchs in it. does this sound right to you. My 4bt puts out 100hp and it has a turbo. Feel free to call me at 623 692 3515 if you can help. Thanks Keith

 

[nexxussian]

Mine is a 5500 pound Land Cruiser with 33 inch tires. I will will eventually upgrade to 35 – 37 inch tires. Occasional light wheeling and towing. The engine is stock 120 hp and will stay that way.

Are you implying that the constant pressure valve body is overkill? Should I just upgrade the pump and servo?

Firstly, my apologies, somehow I missed your reply.

No, I do not believe the CP valve body is overkill in these applications.

Alto Reds with matching Koelene steels are a good investment, I would invest in a "the beast" sun gear shell, and find planetaries with as many pinions as you can.

I forget what it's called, but there is a press on sleeve that reinforces one of the splines connections in there.

All that and a high vane count pump is good.

Oversized servos are up to you, all the heavy internals and the high flow pump is an attempt to make the trans hold roughly 5 times the torque it was designed to handle below 1000 RPM.

As a bonus, I would use an aftermarket, Kevlar band. They tend to be closer to round when applied for better grip, and being closer to round tend to release more fully for generally better cruise economy and lower temps.

 

[eod1]

I've found the Beast sun gear shell, Where do I find the right high vane pump and oversized servos.

 

[Floridan Surfer]

Do Internet search for PATC transmissions. I just ordered the servos and a few springs that will increase Line pressure. As far as the pumps, I believe the 87 and up transmissions have The 10 vane pump. There is also a 13 pain pump, but I have heard that these pumps tend to break.

 

[eod1]

I talked to a friend that works for Borg Warner Specialty Division. He has done a lot of crazy things with the 700R4. I asked if I could put a spin off filter on a 700R4 he said yes. So I put a remote filter in the cooling line on the way back from the trans cooler. He said you could not put one inline coming out of the trans because the fluid just left the converter and needs cooled first. It works great and I can change it out a lot faster then pulling the pan. I still need to pull the pan, but I know I just added another firewall to keeping my trans safe from debris.