TH350 and 700R4 .... (1 Viewer)

[woody]

Tossing ideas between the two right now....

Local builder is doing some checking but the tentative plan right now is:

TH350
aftermarket 2.75 1st gearset
reverse pattern valve body (still deciding on full manual or not)
lockup torque convertor, about 1100 actual stall (electric switch for locking)
Lokar shifter? or gated shifter for easier reverse/first changes?

mating this with a JB conversions shortkit to a D300 case.

I've know the OD of the 700R4 is a waste of effort, tho it does offer a 3.06 1st. TH350 is shorter and the pan isn't quite as wide for more d-shaft space.

Thots and opinions? I know there are a few automatic experts out there.....

 

[tonkota]

The 700R4 is a pile. It needs to be kept cool to last very long. I'd use the TH350 or 400. The .25 difference in ratio isn't much either. Plus, when the 350 wears out, very cheap to replace compared to a 700R4.

 

[Gumby]

Why reverse valve body? I guess if you went with a gated shifter, you could go from r to 1st easy.

TH400 to long and wide for you? I like the bulletproof-ness of the 400.

Are you going with a centered rear?

Hopefully, I'll have the 40 ready in a couple of weeks and you can check out a 400 with a doubler and Toy case. Even if it's not ready, you're welcome to stop in Naperville on you're way past on Friday and check lengths and angles and such.

 

[woody]

Reverse VB for the fast 1 to R shifting

TH400 is a power soaker....plus length and width...

no doubler...just a 4:1 D300 behind it w/ 32-spline outs...clocked flat.

 

[lx450landcruiser]

i like my 400 but i will admit its long. someetimes i think i should have gone with a th350 but then its not as strong. the 400 is strong and smooth though.

 

[orangefj45]

700s are not a pile, if they're built right.

i ran the same thoughts thru my head for the cruggy buildup and this is what i'm gonna run.

th350 with lockup converter and an atlas.

pros and cons?!
th350 is short, cheap to build and lightweight, readily available. adapters are no big deal. the "lockup" converter option is nice especially for compression breaking. good pan to front driveshaft clearance as well. any moron can build one.

cons: not the strongest trans in the world, but i had one behnind a fairly healthy big block in a fullsize truck on 38s for years and it held up fine. and that was in my youth. enough said.
gearing in first is only 2.48:1, but can be replaced with the low gear set (expensive). there is NO manual valve body available for the th350c (lockup version). also, the lockup converters are not super sturdy, but can be built up.

 

[orangefj45]

The 700R4 is a pile. It needs to be kept cool to last very long. I'd use the TH350 or 400. The .25 difference in ratio isn't much either. Plus, when the 350 wears out, very cheap to replace compared to a 700R4.

when's the last time somebody "wore out" a transmission in a rock crawler?!

and .25 ratio difference might not seem much, but figuring in torque multiplication and the fact that percentage wise it's a huge difference from 2.5 to 3.0 will make more than a noticable difference.

 

[Bailey]

Same situation here Woody, I got a TH350 sitting in the shed given to me for free ( that someone is saving up $500 to buy from me - hard to turn that down). Been thinking about buying a 700R4 from Bowtie Overdrive Transmissions. Need more info here. If you got an opinion or experience, anything from drivablity to other conversion issues I'm interested in hearing them. Please post.

 

[woody]

As I was searching early this morning, I located one thread somewheres where 700R gearsets were successfully installed in the TH350 case, providing the 3.06:1 first...they just skipped the OD portion. Course, I can't find it now, but may locate it this weekend again...

350 with the 2.75 set is 45:1 crawl with the 4:1 t-case and 4.11 axles...
700R is 50:1 crawl

I read about 50 threads on PBB before that damn place finally just quit working this afternoon...musta started it's holiday early.....

low gearset is $460 at Summit, reverse VB's are in the $220 range.

gonna talk more with my builder after t'giving....see what he finds and what cores he has avail....

 

[orangefj45]

you don't have to go to bowtie overdrives to get a decent th700.

stuff to look for:
get a th700 from 1988 thru 1992. they're also known as the "auxillary valve body" th700. they have all the factory upgrades. some aftermarket rebuilders and vendors claim that they install "HD components". most of that is a load of BS; they use the factory upgraded parts.
if you decide to get a th700, find a reputable shop in your area and have them built it to your specs. ask them to install a HD "sungear shell" (also known as "the beast"), cause that's the weak link in a th700.
pros: low gearing in first and OD for a DD that's great for the freeway. lockup torque converter reduces the engine rpms even more on the freeway and reduces the amount of heat created in the trans. parts are readily available.
cons: pretty dam long for a cruiser, especially with the adapter and t-case. makes for a very short rear drive shaft. adapters are not cheap. you might have to run a special front drive shaft to clear the trans pan. you will have to run a minimum 1" body lift or the t-case will hit the bottom of the tub and will hang awful low in the chassis. you have to run a lock-up harness in order for the converter to run properly. can be scratch built or bought from painless,..... . you have to run a good cooler, not some boneyard POS.

th700s are more expensive to build but they are a good transmission. i will be installing one in my fj45lv project. and i'm putting one in my wife's fj60 with a doubler behind a vortec. if that tells you anything.



AUTOS RULE!!!!!!!!!!!

 

[HI^C]

i have been playing this one for awhile.

My limited working with the th350c, is small pump, stock would not be able to lockup in all gears only 3rd (pressure?), I have been wondering about this trans and its abilities.

"""low gearset is $460 at Summit, reverse VB's are in the $220 range.""" YUCK that would get a good build start on a 700r4 and be ahead in gearing.

GLIDE? just cause.

 

[cruiserrg]

Considering the cost of the deeper gears you might be ahead doing a 700r4. I wouldn't think rebuild costs are much greater with a 700r4 vs th350. I would also research the lock-up TH350, it might me harder to locate as most I believe were no-lockup...and 700r4 already come with lockup converters.
Just some thoughts.

 

[helocat]

Brian if it helps my 700R4 was an off the shelf standard rebuilt trany that was purchased to go behind my 305TPI my 79’ started out with. For the last 3yrs that 305 has been a 383 TPI and I have been waiting for the trany to start bitching…nothing. Orange has it right, a good cooler and I have one, helps keep it alive. Don’t discount the OD, it actually helps in a trail crawler since you can stay down low and just let the trany kick in the OD sprinting to the next obstacle. The only down side with them is the custom front drive shaft you need to clear the pan. Yet I have not had any issues with the front shaft. When its time to replace I will be putting in another R4 but the next will be custom built.

Mark


BTW: W' Harold of Over The Hill 4x4 has talked in the past about his trany builder putting the R4 1st into a T350. You might give him a call. (call not e-mail, he does not check e-mail all the time)

 

[hammerhead]

Similar story here... my wifes Suburban is a real scorcher of a 383 and that 700 puts up with more abuse than I had imagined. My brother built it with the aforementioned upgrades and it has been through the ringer for about three years and counting. The cooler is of key importance. He set ours up with a mongo cooler and electric fan. You may laugh and say it's only my wifes rig but she drives it hard and Burbs are heavy turds. Also, we live in the mountains.

I'm gathering the pieces to rebuild my '69 into a crawler and I'll be using a 700...

 

[Gumby]

I'm picking up a G2500 tommorow afternoon for the engine (and TBI ). According to car-part.com it has either a TH400 or 700R4 in it, although it would be a 2WD app. I'll know tomorrow when I pick it up if it is the OD tranny or not.

Can't beat the price if you want it...

 

[wngrog]

My 4L60 is the bomb. You say the OD is a waste, but I use it all the time on the trail when going from trailhead to trailhead without knocking it out of 4LO.

Also, hit the road to the trail and it is nice.

That said, the best part of the 700/4L60 is the first gear. The bomb

 

[orangefj45]

My limited working with the th350c, is small pump, stock would not be able to lockup in all gears only 3rd (pressure?), I have been wondering about this trans and its abilities.

pump pressure in any transmission is regulated via the "pump regulator valve" down to about 150 psi, and that's in any gear. what gear you're in has nothing to do with the converter's ability to lock up.
if the pump pressure was not regulated, it would reach upwards of 1500 psi, and that would blow a hole right thru the case.
th350c transmissions are set up from the factory to only lock up in 3rd gear by running the harness for the solenoid thru a "3rd gear pressure switch" which basically opens when the transmission is in 3rd and then activates the solenoid. eliminating this switch will allow you to lock up the trans in any gear. i would not recommend doing that with a stock lockup converter, be it in a th350c or a th700. you should get a hd converter built for that application, and they don't cost a whole lot more. needs to have a stronger lockup piston for sure.



and as far as core go, th350c can be found in any late 70s up to 1981 passenger car like a camaro or trucks and suburbans. i have 2 cores at home, and both of them are the th350c HD with the aluminum 6 blt inspection cover. just do some digging thru your local pick-n-pull and youll find em. the only external difference to the th350c is that it has an electrical connector on the driver side just above the pan right behind where the shift linkage attaches.

i can post pics if needed.

 

[tonkota]

700s are not a pile, if they're built right.

OK, They suck. POS. Crap.

 

[orangefj45]

are you being sarcastic or ignorant?!

 

[Mace]

Igernant...