I Have the stock tuxedo park 4.88 locked axles, the dauntless 225 engine, and a failing t86aa tranny. With this set up I'm able to go about 55 mph. I absolutely love this engine in jeeps so I truly want to keep it and I'd also like to keep those hard to come by axle gear and locker in the rig, not just because its hard to come by but I love the feeling they give while driving it,but I want it to go freeway speeds because I'd like to make it my daily. Since Its needing a new tranny I've been looking into putting an automatic with an overdrive in there. I've really been looking into the th200r4 because it's got a pretty good OD in it, it doesn't require a computer, and it will fit the engine with out an adapter. My question is will I need to get a different flywheel or anything to switch the dauntlessvery less to an automatic? Because I love the low end power the dauntless' heavy flywheel gives so I really don't want to change it. Any help/guidance/knowledge is greatly appreciated!
So installing that flex plate should be the only thing really needed to use an automatic?
tarry99
Member
- Joined
- Oct 29, 2012
You could fix your current transmission and put a Warn 25% OD in there behind your Dana 18...........No change in drive shaft length , no new cross member, no need for a new flywheel .............and you get a 3.66 final drive ratio that will easily get you to 70 mph if you like.............really the perfect fix for a Jeep with a D-18 and manual gear box............PM if your interested in a Warn OD......I know where one is.
Daryl
Sponsor
- Joined
- May 25, 2006
Much easier to put in an automatic if you get a later V8 grill which mounts the radiator farther forward then move your engine as far forward as you can. Every inch makes a difference when putting an auto in a short wheel base Jeep. If done this way, you can run a t350 and still have a rear driveline about 15" quite easily.
- Joined
- Aug 10, 2003
Hi - where to start?
Easiest one first - an automatic does not have a flywheel. Instead it has a flexplate. The flexplate has the starter teeth and connects the crankshaft to the torque convertor. The flexplate is very light compared to the flywheel, but you have no choice about this. Have you ever driven a 4WD with an automatic over rough terrain? It's a different style of driving, using both feet. Apply brake and throttle at the same time and release the brake to move forward. The engine momentum you are so fond of with the heavy flywheel is not relevant with an automatic.
The usual choice of automatic for the 225 in a CJ-5 is the TH350. It's fairly short, which is a major consideration. Your rear driveshaft is short, and you do not have room for a long automatic transmission. Start by reading the Novak site about the TH350 and CJs. You will need an adapter to your transfer case.
Depending on how tall your tires are, you should be able to drive faster than 55. It will be loud, but the 225 is just fine at those speeds for as long as you can stay behind the wheel.
Why are you not considering the Warn overdrive? It works really well with the 4.88 axles and will drop your highway RPM by 25%.
Easiest one first - an automatic does not have a flywheel. Instead it has a flexplate. The flexplate has the starter teeth and connects the crankshaft to the torque convertor. The flexplate is very light compared to the flywheel, but you have no choice about this. Have you ever driven a 4WD with an automatic over rough terrain? It's a different style of driving, using both feet. Apply brake and throttle at the same time and release the brake to move forward. The engine momentum you are so fond of with the heavy flywheel is not relevant with an automatic.
The usual choice of automatic for the 225 in a CJ-5 is the TH350. It's fairly short, which is a major consideration. Your rear driveshaft is short, and you do not have room for a long automatic transmission. Start by reading the Novak site about the TH350 and CJs. You will need an adapter to your transfer case.
Depending on how tall your tires are, you should be able to drive faster than 55. It will be loud, but the 225 is just fine at those speeds for as long as you can stay behind the wheel.
Why are you not considering the Warn overdrive? It works really well with the 4.88 axles and will drop your highway RPM by 25%.
That's a great thought daryl! I think that would be a great route! The reason I don't want to repair the t86aa then install the OD is because that's a lot of money to put into a not very durable tranny! Plus I figured it would be convenient with an automatic.
- Joined
- Aug 10, 2003
Does an adapter exist for the 200R4? You still need to adapt the transfer case to the transmission. Is a 200R4 strong enough for the 225?
You understand what you are taking on with an automatic swap? Moving the engine forward will have side effects .... exhaust, cooling plumbing... it could be done neatly, but it will be a lot of work. With an automatic, you will want to upgrade the brakes, and a transmission cooler would be a good idea.
You need a flexplate that works with the 225 and bolts to the 200R4 torque convertor. The 225 is external balance, so your choice of flexplates may be limited. A flexplate exists for the TH350 since that combination came in cars, but re the 200R4 I don't know. Research needed.
If you want a more durable transmission, a T-15 would be a significant upgrade. A truck 4-speed would be even stronger, but more to do to make it fit.
You know that you can use the T-90 gears in a T-86 case, as long as you replace everything? Lots of support for the T-90 in the aftermarket.
You understand what you are taking on with an automatic swap? Moving the engine forward will have side effects .... exhaust, cooling plumbing... it could be done neatly, but it will be a lot of work. With an automatic, you will want to upgrade the brakes, and a transmission cooler would be a good idea.
You need a flexplate that works with the 225 and bolts to the 200R4 torque convertor. The 225 is external balance, so your choice of flexplates may be limited. A flexplate exists for the TH350 since that combination came in cars, but re the 200R4 I don't know. Research needed.
If you want a more durable transmission, a T-15 would be a significant upgrade. A truck 4-speed would be even stronger, but more to do to make it fit.
You know that you can use the T-90 gears in a T-86 case, as long as you replace everything? Lots of support for the T-90 in the aftermarket.
oddfirejeeper
Active Member
- Joined
- May 5, 2004
"I don't want to repair the t86aa then install the OD is because that's a lot of money to put into a not very durable tranny!" well if the tranny lasted this long and you rebuilt it then by all means it should last that long again
- Joined
- Aug 10, 2003
The low-end torque does not come from the flywheel. Did you understand what I posted above about driving style?
The heavy flywheel was used to smooth out the rough idle of the odd-fire engine. The heavy flywheel has more momentum, but it actually saps power because you have to accelerate both the heavy flywheel and the Jeep. Storing momentum comes at a cost.
With an automatic, you spin the torque convertor and all the fluid inside of it. The engine is smoothed out by that load.
The PROPER flexplate will have balance weights to keep the engine balanced. The flywheel has the same balance, but the heavy flywheel is not needed for balance.
- Joined
- Nov 22, 2003
My $.02-
go with a granny low 4 speed of some description & the OD- that will take care of your low speed torque and top speed concerns. Autos have a place if you're into hard core rock crawling or have a bum clutch leg but other than that in a short wheelbase CJ you're opening up a
H.
go with a granny low 4 speed of some description & the OD- that will take care of your low speed torque and top speed concerns. Autos have a place if you're into hard core rock crawling or have a bum clutch leg but other than that in a short wheelbase CJ you're opening up a
H.
colojeepguy
Colorado Springs
- Joined
- Apr 4, 2010
Both AA and Novak list a trans/tcase adapter for a 700R4, but nobody I'm aware of makes one for the 200R4.
If it was my Jeep I'd put an overdrive in it and either adapt a T 15 or put the T90 gears in your trans.
If it was my Jeep I'd put an overdrive in it and either adapt a T 15 or put the T90 gears in your trans.
For what its worth, Buick had an odd-fire 231 for the first couple years after they revived the V6, maybe up to 1975 or 1976. Many of those cars had automatic transmissions, so an appropriate flexplate and converter.
The late 1960's Jeepsters could be had with the odd-fire 225 and automatic (th400) , so there is another source for the flexplate.
The 200R4 you are considering should be robust enough, after all, it was used in the late '80s Buick Grand Nationals with turbos.
Personally, I would rebuild with a T90 or a 4 speed.
- Donny
The late 1960's Jeepsters could be had with the odd-fire 225 and automatic (th400) , so there is another source for the flexplate.
The 200R4 you are considering should be robust enough, after all, it was used in the late '80s Buick Grand Nationals with turbos.
Personally, I would rebuild with a T90 or a 4 speed.
- Donny
Mike C
Member
- Joined
- Feb 19, 2007
The TH200 4R can be built to take 1000+ hp but the Buick Grand National was the only relative high power OEM use. And it was never in a 4x4. It has a LONG integral tail shaft housing so won't bolt up to any T-case so would require divorce mounting which is pretty much a deal killer in a Jeep Universal. I am a fan for street vehicles, as the first gear is not so steep as the TH700R4 and the OD is higher. But for an on/off-roader, the TH700 probably a better choice.
But if it were mine, I'd be looking at doing a SM465/T18 type swap which I think is the cat's meow for a CJ.
But if it were mine, I'd be looking at doing a SM465/T18 type swap which I think is the cat's meow for a CJ.
- Joined
- Sep 6, 2014
*******,
I'm the guy who bought the frame from you.
You should come down to cottonwood and drive my Jeep. Once you cruise down the freeway with an O.D. you will never be the same. I regularly drive my jeep back and forth between Cottonwood and Redding, 20 miles on the freeway and don't bat@ 65-70 and don't bat an eye. Iv'e driven from Cottonwood to Eureka and back with 3 adults in the jeep plus luggage and never dropping below 55mph the whole trip. My sig lists all my jeep specs.
Kyle
I'm the guy who bought the frame from you.
You should come down to cottonwood and drive my Jeep. Once you cruise down the freeway with an O.D. you will never be the same. I regularly drive my jeep back and forth between Cottonwood and Redding, 20 miles on the freeway and don't bat@ 65-70 and don't bat an eye. Iv'e driven from Cottonwood to Eureka and back with 3 adults in the jeep plus luggage and never dropping below 55mph the whole trip. My sig lists all my jeep specs.
Kyle
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ITLKSEZ
Watching a toddler play w/a loaded gun
- Joined
- Aug 13, 2015
If you absolutely need an automatic and an overdrive, I'd personally go with the th350 to a D18 with a Warn OD. Reliable, available, tried and true, short-ish...
BUT... I'd really consider a different route for the same outcome if your main goal is freeway speeds, and get a lower crawl ratio as a byproduct. Go with a T-18/SM420/SM465/NP435 granny trans and drop your axle ratios to 3.73s. Avoid OD altogether.
Right now your crawl ratio is a measly 33.49:1.
With an SM465 and 3.73s, your final crawl ratio would be 60.1:1.
With that setup, your second gear would almost be identical to your current first gear, and it would be syncronized. (33.5:1 vs 32.8:1 low range, 13.6:1 vs 13.4:1 high range)
BUT... I'd really consider a different route for the same outcome if your main goal is freeway speeds, and get a lower crawl ratio as a byproduct. Go with a T-18/SM420/SM465/NP435 granny trans and drop your axle ratios to 3.73s. Avoid OD altogether.
Right now your crawl ratio is a measly 33.49:1.
With an SM465 and 3.73s, your final crawl ratio would be 60.1:1.
With that setup, your second gear would almost be identical to your current first gear, and it would be syncronized. (33.5:1 vs 32.8:1 low range, 13.6:1 vs 13.4:1 high range)
- Joined
- Aug 10, 2003
Mmm. Not an expert on optimizing automatics for off-road purposes, but I believe you don't need as low a crawl ratio with an automatic as you would with a manual transmission. The two-footed style means you don't have to move forward until the stall speed of the converter is reached... this is typically 1500-1800 RPM for factory converters. Plus the converter multiplies torque from the engine at stall by roughly 2:1, so in terms of torque available you have twice the reduction of a comparable geared vehicle. And, you can control your forward speed by releasing power as you need it by letting up on the brakes.
The truck 4-speeds are great if that's the style of driving that you want. An automatic will be different, and have different trade-offs.
The truck 4-speeds are great if that's the style of driving that you want. An automatic will be different, and have different trade-offs.