Buying a TH700R4 core for a CUCV

[stationjj]

I have a 84 M1009. Currently I have no major issues with my Th400 Transmission.

I understand that our CUCVs are over 26 years old, and will become rare. I try and be proactive rather than reactive to problems. If I can buy pieces at a time.

So I would like to buy a 700r4 that will work on a CUCV. I have looked at the many threads concerning a 700r4 on a CUCV.

My questions are more towards buying a broken or working core for a CUCV. This is what I have learned so far.

Finding a TV cable Bracket for a 6.2 diesel is hard
A TH700R4 from a gasser needs to be from an 8 cylinder
A 90s model is preferred.

I understand that I will need to change T converter plate and other things.
My concern is buying a core for future use.

What do I need to consider in buying a 700r4 core for future use?

Thanks,

stationjj

 

[Warthog]

The 700r4 w/overdrive might be doggy in the M1009 with stock 3.08 gears (never tried it)

If you are looking for a core, try to find a 4x4 version from the late '80s or early '90s.

The 4x4 case is beefier and has all the right parts. You can make a 4x2 work but will spend some $$ on the correct parts.

I have found two TV cables brackets. One at my local savage yard for free(only diesel I have seen there in three years of looking) and one I bought on fleabay for $75.

You will need a new torque converter and governor.

I have been looking for (and bought one) 1/2ton 4x4 suburbans with 700r4 and either 208 or 241 transfer cases for a future project.

 

[HoJoPo]

I was lucky enough to find a complete 6.2 engine / 700r4 / NP208 combo for sale, out of a civvy pickup that was re-powered (with a 454). The engine was bad (cracked head), but everything else was good. If I remember correctly, it was in the engines / transmissions / transfer cases section of the Pirate 4x4 board, though it might have been off of Craigslist. He was asking $400 for all three together, I picked them up for $200.

Oddly, even though it was a diesel combination (all bolted together), the transmission shop said it had a gasser torque converter in it, so the 700r4 may not have been the original one for the truck. Shows you have to check things even if they come together. I had the transmission rebuilt with the correct converter and stronger internals, they also went through the transfer case and replaced wear parts / seals.

I agree, with the stock gears on a 1009, you'll probably only be able to use overdrive on the flats. Re-gearing to 3.73 would probably be good enough, depending on tire size.

 

[panzerwillie]

With out a turbo maybe a little slower on OD but my m1009 has a turbo and i play around with 2.73 and even 2.56 gears still has plentty of power with even the 2.56. I am running the stock 3.08 now with 32x12.5x15 and at 65MPH is around 2400RPM, converter maybe a bit looser than before cause it has 70k on the factory one, with a OD and lock up would be better on the HWY probably would be around 2000RPM i have OD here ready to go just got other projects ahead so for now is staying like that unless something breaks gut luck with your OD if you do it..

 

[cliffyp]

With 3.08 gears, 32" tires and the 700r4's 0.7 overdrive you'd be under 1500 rpm's at 65. Unless you were on a long flat road I don't think the overdrive and stock 3.08's go well together. My 1028 with 4.56 gears in overdrive doing 60 is about 2000 rpm's.

 

[southdave]

I belive the 4l60 is the same case they are everywhere ... so I am told look

 

[cliffyp]

92 or 93 is when they changed the name from 700r4 to 4l60. Some time in 93 or 94 it became 4l60E, E for electronically controlled. You don't want a 4L60E unless you want to get a computer controller. If you're getting a controller you might as well get a 4L80E

 

[panzerwillie]

I dont see how you can drop almost a 1000 rpm with 700r4 but you guys can continue your delegation signing off this thread enjoy it

 

[southdave]

92 or 93 is when they changed the name from 700r4 to 4l60. Some time in 93 or 94 it became 4l60E, E for electronically controlled. You don't want a 4L60E unless you want to get a computer controller. If you're getting a controller you might as well get a 4L80E

I thought it was same case you stuff the 700r4 into it

 

[ODdave]

4l60E dose not have a governer housing therefor cant be converedt to non electronic. (amongst other things)

 

[southdave]

I was aparently missed lead, I thought that was supper duper 700r4 was more less 4l60case with corvett internals for 700r4 and shift kit..

 

[cliffyp]

I dont see how you can drop almost a 1000 rpm with 700r4 but you guys can continue your delegation signing off this thread enjoy it

(0.00595) * (RPM * r) / (R1 * R2) = vehicle speed in miles/hour

0.00595 = conversion from inches per minute to miles per hour
RPM = engine speed, in revolutions/minute
r = tire radius (midpoint to pavement)
R1 = transmission gear ratio
R2 = axle ratio

So with 4.56 gears, 31 inch tires, in a TH400 third gear turning 2500 rpm:
.00595*(2500*15.5)/(1*4.56)
230.56/4.56
50.56 mph
Same rpm's with 700r4's 0.7 4th gear
.00595*(2500*15.5)/(.7*4.56)
230.56/3.19
72.27 mph

But it's much easier to use a calculator like this site: http://www.csgnetwork.com/multirpmcalc.html

 

[ODdave]

4l60 & 700r4 are the same just different names, the 4l60e is different. The later designation is more descriptive.

4- number of speed
L- Lonitude mounted
60- torque scale rating

4l60=700r4
th400=3L80

 

[southdave]

ODave meet a crusty dude today who worked with your Dad way back when.. it get really confusing looking at all that GM crap and cross reference numbers thanks for the clarification..

 

[poncho457]

700r4 gear ratios: 3.06:1 1st 1.63:1 2nd 1:1 3rd od 0.70:1

th400 gear ratios: 2.48:1 1st 1.48:1 2nd 1:1 3rd

The lower first gear in the 700 makes it good swap when combined with a high axle ratio such as a 3.08, and there is nothing wrong with running 1500 rpm at 65 if you need more power it downshifts.

The only downside is most have a weak sprag (this can replaced) and mis adjusting the tv cable can destroy the trans.

 

[patracy]

I dont see how you can drop almost a 1000 rpm with 700r4 but you guys can continue your delegation signing off this thread enjoy it

2800 x .7 = 1960. That's almost 1K rpms.

 

[southdave]

2800 x .7 = 1960. That's almost 1K rpms.

It also drops another 300rpm when the torque convert locks up in 4th.. well at least mine does.. acording to the tach..

 

[cliffyp]

I have a question for you other 700r4 users. I'm trying to decide on best practice for around town driving.

I go through a lot of stretches of 100 yards or so, then stop light, then another 100 or yards. Traffic flow gets up to 40-50 maybe more if you make a green. I generally leave it in 3rd but want to shift to 4th or lock my converter in 3rd to lower the rpm's. I'm not sure that all the converter lockup then unlock is good but I'm not sure that driving that much at speed with it unlocked is good because of the extra heat from the converter slipping.

It seems like there're four choices:
1. Leave it in 3rd converter unlocked
2. Leave it in 3rd and lock converter which then unlocks as you stop at lights
3. Let it go up to 4th but leave the converter unlocked
4. Let it go up to 4th and lock the converter

What's your style of choice and any why behind it?

 

[wayne pick]

For light to light rush hour drag races, 3rd gear lockup is the way I would go. No need to get it shifting in and out of 4th gear. The 700R4 should never be run in unlocked 4th gear. When im putting around town, I leave it in 3rd gear, locked up. On the highway, I let it go to 4th, locked up.