New to Automatics in a Crawler

kickdeez · Jul 18, 2022

In need of some advice/knowledge. I come from the world of toyota 5 speeds and doublers on doublers. Just got into a new (to me) buggy with an automatic transmission that I need to have rebuilt. Relevant specs are:

700R4 transmission
RMVB
Low to middle 2000 rpms stall converter (not entirely positive)
B&M Super Cooler with fan on switch...Temps generally stay in the 160 - 180 range
5.38 axle gears
Atlas 2 speed with 4.3 low range
More or less stock 5.3L LS
Currently 39" reds, but switching to 42" Treps
3,800 lb rig
80% crawling, 20% put my foot through the floor cuz I like the sound it makes, and that's just east coast wheelin. NOT a bouncer.

Transmission was rebuilt in 2019, and performed well until now. When I got the buggy, it was slipping in 3rd gear. This weekend it completely grenaded. I think I'd prefer to get this one rebuilt as strong as I can get it, as opposed to swapping to a different transmission. Swapping is just a ton of re-configuring in an already tight package. Certainly these 700R4s can be built to be strong enough and reliable enough for a crawler, right? I know they have gotten a bad rap for a while, but I was reading that it was primarily the result of poor adjustment of the TV cable.

My questions are:

1. Who are the go-to transmission builders/re-builders on the east coast? The closer to Charlotte, NC the better. But I'm certainly willing to drive or ship this transmission to the right person for the job.

2. What parts/upgrades do I need to be familiar with and make sure are included in a rebuild? Assume that I know zero things about automatic transmissions.

3. What rpm range should I be in for the stall on the converter?

4. Is 3ish years a reasonable life expectancy out of a "built" 700R4 for what it's being used for? Just want to make sure I prepare myself and budget for major maintenance items appropriately.

5. Should I be considering a new unit from like TCI or Monster (or other performance transmission manufacturer) instead of getting this one rebuilt?

Lil ugly · Jul 18, 2022

I am not knowledgeable as to the parts that you need to upgrade on the 700r4. Heat is always the biggest killer of auto transmissions beyond a poor set up. 160 to 180 is not bad for that transmission. The RPM range depends on your engine and gearing, it helps align tranny lock up with your vehicles powerband. A stock truck is usually in the 1800 range, you will likely need to stay in the 2000 to 2100 range. Remember though the higher the stall the more heat you will develop. A quality torque converter is a must for keeping your tranny alive. Hard to put a time on how long a tranny will survive in this sport. Depends on too many factors, like heat, fluid changes, quality of build, how hard its beat on, how often it gets used etc. Definitely stay away from Monster transmission. I have had good luck with my parts from TCI but have never bought a tranny from them

Bebop · Jul 18, 2022

No TV cable on a full manual TH700 like this one.

Get the converter rebuilt. And have it re-stalled if you don't like how it performed. I've been very happy with PTC.

As far as rebuilding the trans that should be enough, no need to buy another one. Just get someone who knows what he's doing. I use a guy in Knoxville, but that may be too far for you. Get someone who knows offroad and he/she will be able to specs the right parts for you. Just know a TH700 isn't the right trans for a hardcore use. It's good for crawling. Basically same thing as a 4L60.

Duration will really depend on use. Some people will slam first to reverse all day and burn them up in no time. Some people's "light wheeling" is other people's hardcore ****.

Do not buy anything from TCI or Monster (from personal experience)

160-180 temp is actually really good. Don't go over 220 and you're fine.

greenlion · Jul 19, 2022

Another vote for call PTC. They build a lot of rock crawler/bouncer trans and convertors. 256-383-6868

ridered3 · Aug 22, 2022

@kickdeez what route did you decide to go with the transmission?

87TPIYJ · Aug 23, 2022

FWIW this was what I had in my old 700r4.

5 pinion front planet
Steel forward clutch piston
Corvette servo
Oversized TV boost valve (K020 by superior )
Main boost is .500
Roller bearings ring gear support (05+ 4L60)
Beast sun shell
Hydraulic lock up (by superior, White spring 2nd highest)
Modified valve body (plate drilled, valves blocked, heavier springs)
2-3 check valve (Sonnax 7701-076)

kickdeez · Aug 23, 2022

ridered3 said:
@kickdeez what route did you decide to go with the transmission?

I actually just shipped it off to Fritts Performance Transmissions in KY on Friday. I talked to a few local shops, and they did not give me much confidence. Fritts came as a recommendation from a buddy that builds turnkey buggies. After talking to Fritts, I knew he was the one I wanted building my transmission. Looking forward to getting it back from him.

ridered3 · Aug 23, 2022

kickdeez said:
I actually just shipped it off to Fritts Performance Transmissions in KY on Friday. I talked to a few local shops, and they did not give me much confidence. Fritts came as a recommendation from a buddy that builds turnkey buggies. After talking to Fritts, I knew he was the one I wanted building my transmission. Looking forward to getting it back from him.

Dlusco · Aug 23, 2022

350 crate motor with 4 bolt main 700r4 trans with Atlas 4 speed

kickdeez · Aug 29, 2022

87TPIYJ said:
FWIW this was what I had in my old 700r4.

5 pinion front planet

Steel forward clutch piston

Corvette servo

Oversized TV boost valve (K020 by superior )

Main boost is .500

Roller bearings ring gear support (05+ 4L60)

Beast sun shell

Hydraulic lock up (by superior, White spring 2nd highest)

Modified valve body (plate drilled, valves blocked, heavier springs)

2-3 check valve (Sonnax 7701-076)

This is really good info! I just realized I'm way outside of my element, so I'm letting a professional handle it all for me. Thanks for the input though!

the78outlaw · Aug 31, 2022

If Fritts doesn't work out for you, there's a guy in Mountain Home, ID, of all places, that has the experience you need to build this trans. PM me for more info if you like.

He built a 4l60 that's been living behind a legit 1,000 hp mud truck for the last 3 years.

kickdeez · Sep 1, 2022

the78outlaw said:
If Fritts doesn't work out for you, there's a guy in Mountain Home, ID, of all places, that has the experience you need to build this trans. PM me for more info if you like.

He built a 4l60 that's been living behind a legit 1,000 hp mud truck for the last 3 years.

Thanks. I'm confident my transmission is in good hands. But if something changes, I'll reach out.

kickdeez · Feb 15, 2023

Guess I could update this with a quick review...2 thumbs way up for Fritts Performance Transmission.

They did a great job getting my transmission sorted out and rebuilt. Upon tearing into it, they found that the pump had completely exploded. It is suspected that inadequate fluid flow/pressure caused the failure. They identified some issues in the valve body and the original rebuild that likely contributed to the fluid flow/pressure issues.

It's all been completely rebuilt with their "stage 1 build", dyno'd, reinstalled in the buggy, and put through its paces on several recent trips. Couldn't be happier with the job Fritts did. Not to mention, he was willing to get on the phone with me multiple times to explain the problems and recommended parts/fixes in a way that even I could understand. He even talked me through some newb installation and operation questions I had. Stand up guy and company. 10/10 recommend.

Pic just because

ridered3 · Feb 15, 2023

@kickdeez thanks for the update on the buggy and review of a transmission shop. Glad to see the buggy out and about again.

Bebop · Feb 15, 2023

kickdeez said:
Pic just because
View attachment 208963

This damn buggy is a looker.

kickdeez · Feb 16, 2023

ridered3 said:
Glad to see the buggy out and about again.

You and me both! I've been having some fun with it. I have trips planned to AOP March 9-12 and Good Evening Ranch April 6-8.

kickdeez · Feb 16, 2023

Bebop said:
This damn buggy is a looker.

It looked really good on the 39" reds. The 42" treps really set it off though, IMHO.

jeeptj99 · Feb 16, 2023

kickdeez said:
Guess I could update this with a quick review...2 thumbs way up for Fritts Performance Transmission.

They did a great job getting my transmission sorted out and rebuilt. Upon tearing into it, they found that the pump had completely exploded. It is suspected that inadequate fluid flow/pressure caused the failure. They identified some issues in the valve body and the original rebuild that likely contributed to the fluid flow/pressure issues.

It's all been completely rebuilt with their "stage 1 build", dyno'd, reinstalled in the buggy, and put through its paces on several recent trips. Couldn't be happier with the job Fritts did. Not to mention, he was willing to get on the phone with me multiple times to explain the problems and recommended parts/fixes in a way that even I could understand. He even talked me through some newb installation and operation questions I had. Stand up guy and company. 10/10 recommend.

Pic just because
View attachment 208963