Any Tips On Building A Turbo 400 For Rockcrawling? Building One With A Tci Manual Reverse Pattern Valve Body And A Tci Rebuild Kit. Going In A Cj7 With A Vortec 5.7, Dana 20 T-case, 4.88 Gears And 37 Inch Tires. How About Torque Converter Selection?
Building A Turbo 400
kodiak77
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Any Tips On Building A Turbo 400 For Rockcrawling? Building One With A Tci Manual Reverse Pattern Valve Body And A Tci Rebuild Kit. Going In A Cj7 With A Vortec 5.7, Dana 20 T-case, 4.88 Gears And 37 Inch Tires. How About Torque Converter Selection?
the 400 in my rig (tho the it is torn down) has the art carr valvebody. this go around i have put a tci breakaway converter (realistically a 2300 stall) in and im interested to see how that does with my 4.3. yes it may sound too high for crawling but i will be running 4.10s this time to start off with. im going to give it a try. my problem with stock stall converters is that i cant get enough of a jump within 6 inches. and the gears and motor will probably put me in the higher rpms anyways. i am concerned about heat, and tho i run a big cooler, if this converter poses a problem i will switch to this "magic" art carr converter ive heard about that has a higher stall but doenst create as much heat when slipping (its called a dual rate or something). see i dont have much patience for sitting still and spinning the wheels beyond a short amount of time (tho i try to finesse everything i can). therefore i like to have wheelspeed when i want it. and with this setup i trying to have my first gear be almost universal - i can crawl but at the higher throttle (still in first) can get some real wheelspeed.
for your converter i would say start with...wait where are you located? if you are out here in the east - run a breakaway (or similar). they work very well in tellico and slippery places. out west, well id say maybe a tci sizzler or stock.
good luck, jeremy
for your converter i would say start with...wait where are you located? if you are out here in the east - run a breakaway (or similar). they work very well in tellico and slippery places. out west, well id say maybe a tci sizzler or stock.
good luck, jeremy
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A couple things to remember are the cooler bypass needs to be in place (modified like a th 350) and not to hit it hard until it warms up - also run two or three trans coolers - the converter selection - just a note i have a 2500 stall it really stalls out at around 3000 in low range it stalls at 1500 just about perfect in low range a little high in in high range - so take your pic- my t-case is a 3.8 - Jesskodiak77 said:
I Live In Idaho And Mainly Run In Utah, Moab Mostly. I Have A Summit 2500 Rpm Stall Converter I Was Going To Try First. Is There Any Thing Else I Need Besides A Deep Pan To Prevent Oil Starvation? Any Other Tricks On Setting One Up? Whats The Best Shifter To Use When Trying To Get From 1st To Reverse In A Hurry?
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I'm interested in what people are doing to keep it from stalling at extreme angles.
The TF-904 in my Jeep will shut the whole damn motor down when I'm climbing really steep stuff, and I don't want the TH400 I'm gonna build to shut me down
The TF-904 in my Jeep will shut the whole damn motor down when I'm climbing really steep stuff, and I don't want the TH400 I'm gonna build to shut me down
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3,492 Posts
As far as the converter goes...that can be tricky as we all know too well. Converters react so different with different setups...ie: gearing, camshaft specs, heads (and relation to cam specs), and vehicle weight to name a few. For most of us it is trial and error...and compromise for the extreme range we use our toys. We want good acceleration BUT we want to crawl, we want to climb AND we want compression braking on the downhill, we have low range and we have high range....a drastic change in gearing. A switch pitch converter may be an option? I have not really seen these in a looong time, it seems like having "two" converters (stall speeds) would be a nice setup. I am sure they are not without their down sides as well.
1975 K5 Blazer 350 FI, 700R4, NP208, 4.56, Detroit's, 33" Mickey Thompsons
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104 Posts
I have a deep pan on my TH400 and I've had my K5 on it's front and rear bumpers at times and never had transmission problems. Also stay away from the plastic thrust washers when you rebuild it and the heat won't bother the transmission as much.
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I don’t have any experience with a TH 400 for offroad use.
I built one twice for a street rod.
The rebuild and valve body mods are very simple.
Everything pulls out the front. I placed everything on a sheet, cleaned it all, replaced the clutch packs and seals, and put it back together the same way.
It worked great on the street, but only lasted a couple passes on the drag strip.
After I drove 35 miles home in 2nd gear and barely made it over the last mountain I started the process all over again.
I called TCI, and they said that I needed to modify my sprag gear (like a free wheel between primary and secondary clutch packs).
My tranny was a 74 model and had 8 roller bearings in the gear.
They said the it wouldn’t last all day (3800# trans am with warmed up 455 and 3.42 R&P)
They said that I needed a sprag gear from a 68 to 72 TH400 that has 16 roller bearings and buy a rebuild kit that replaces the 16 bearings with 32 bearings.
I went to the boneyard, pulled the right sprag gear, rebuilt it (not using TCI components since they neglected to tell me this in detailed phone conversations with them).
The tranny was bullet proof.
Toward the end of that car (it was an old beater and destined to be stripped and hauled to the bone yard), I flat abused that transmission. I was running a Firestone L-60 (P275/60).
I went full throttle in reverse, dropped it drive, cut donuts, hit reverse and hardly ever lifted the throttle. I puked out some 10 bolt axles, but the tranny never missed a beat.
I did this on several occasions just to see how much it could take. It took it all.
So, you need to specifically ask about the sprag gear in your application.
I built one twice for a street rod.
The rebuild and valve body mods are very simple.
Everything pulls out the front. I placed everything on a sheet, cleaned it all, replaced the clutch packs and seals, and put it back together the same way.
It worked great on the street, but only lasted a couple passes on the drag strip.
After I drove 35 miles home in 2nd gear and barely made it over the last mountain I started the process all over again.
I called TCI, and they said that I needed to modify my sprag gear (like a free wheel between primary and secondary clutch packs).
My tranny was a 74 model and had 8 roller bearings in the gear.
They said the it wouldn’t last all day (3800# trans am with warmed up 455 and 3.42 R&P)
They said that I needed a sprag gear from a 68 to 72 TH400 that has 16 roller bearings and buy a rebuild kit that replaces the 16 bearings with 32 bearings.
I went to the boneyard, pulled the right sprag gear, rebuilt it (not using TCI components since they neglected to tell me this in detailed phone conversations with them).
The tranny was bullet proof.
Toward the end of that car (it was an old beater and destined to be stripped and hauled to the bone yard), I flat abused that transmission. I was running a Firestone L-60 (P275/60).
I went full throttle in reverse, dropped it drive, cut donuts, hit reverse and hardly ever lifted the throttle. I puked out some 10 bolt axles, but the tranny never missed a beat.
I did this on several occasions just to see how much it could take. It took it all.
So, you need to specifically ask about the sprag gear in your application.
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