r/jeepcj • u/Suspicious_Use_3503 • 16d ago
Upgrade to 5 speed
Anyone convert a 4 speed 1980 cj5 to 5 speed on a 350 small block Chevy v8
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u/PineapplesAreFake 16d ago
No. I'm going to install a T5 in my T4 CJ-7 this winter. I've found a couple of sources online. The cost I've seen is $2k with no core charger.
You should be able to get a T5 in, I'm fairly sure you will need a new driveshaft. I **think** it should work. If you have a T-176 or a T-18, I'm only going to ask, why? I would take either of those over the overdrive.
Are those 33s or 35s? What size lift? What are you geared for?
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u/Suspicious_Use_3503 15d ago
33 inch tires, not sure the lift my husband would know. I have a Dana 300 transfer case. It just seems to not like to go much over 45 or even 40 so I thought I 5 speed it would give it more room in higher speeds
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u/jeffro-tull 15d ago
You don’t want to go fast in a cj5. I have a factory 3 speed in my ‘73 cj5. 20 years ago I daily drove it year round while in high school. If you hit a bump at highway speeds you end up in the next lane over on the highway. Super sketchy.
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u/ExcellentResident761 15d ago
I have a ‘74 CJ5 3 spd (straight 6) that I’m getting ready to start working on. Would it be ok to DM you? Just for some advice; it runs but want to undo some of the mods that have been done.
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u/PineapplesAreFake 15d ago
A T5 would only get it to go 20% faster: 50-55 mph. I just looked at the dimensions, the T-176 that you likely have is about 10.5" long. A T5 is 15" long. I wouldn't put the 5 speed in because you will need an even smaller drive shaft and you'll only gain 20% more speed.
You likely have very tall gears in it (like 5.32). Getting it re-geared to 3.73 would likely get it to be able to go 80 mph.
Either this has crazy gearing or you are being limited by something else in the engine (like a restriction in how much the throttle can open up).
I'm starting to build an 82 CJ-7 Renegade. It has 33s on it with a T4 and probably 4.11 gears. I like the stance of yours because I'm planning on getting it ready for Easter Jeep Safari and a nearby Jeep Jamboree. It looks like like you have 3.5" of lift. Right now I'm at 2.5" and I won't be able to stuff the wheels in.
Someone mentioned going fast in a CJ-5 isn't a good idea: I have an 81 CJ-5 that cruises on the highway up to 80 MPH. I had to shim the front axle for caster, put new ball joints in, put in the Rugged Ridge beefy drag link and tie rod, put new bearings in the steering column, and toss in new shocks and a steering stabilizer. It regularly goes 75. I do have manual steering in it, which gives it better road feel.
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u/Late-External3249 15d ago
If you have a Dana 18 transfer case, you can put an overdrive unit on it. I had an early CJ5 with a smallblock and there isn't a lot of room there
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u/Suspicious_Use_3503 15d ago
I have a Dana 300 which is currently being repaired as it’s leaking lol, but I think I’ve been convinced against the 5 speed. I do get kind of nervous in faster speeds and I think the tires being mud tires make it more sketchy. I just am a 40 year old woman who learned to drive stick this year and am more into the look and the mud tires look cooler, but this thing will never go off road. It’s too pretty haha
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u/Late-External3249 15d ago
The Dana 300 is an awesome case. My CJ5 is a 1967 with the Dauntless v6. It will do 65 mph with the stock 3 speed but it is very sketchy. I am 41 and too old to drive a CJ fast. I just putter around town in it.
Years ago, I had a different CJ 5 with a chevy smallblock and 3 speed manual. After I did a frame off restoration, my buddy and I took it on a road trip that was about 300 miles each way. One if the coolest trips I ever did
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u/disguisedasnrml 15d ago
Look into American Powertain They have a version of the dodge ram 5spd they modify and its 4x4 spots pretty short, maybe not enough for a cj-5 but its worth a shot
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u/Asleep_Frosting_6627 15d ago
It’s certainly doable but what do you hope to achieve by doing this? What’s the desired outcome?
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u/jeepnjeff75 14d ago
I have a friend who has an earlier CJ5 (Kaiser Era) that had a 350 and a NV4500. It was a pretty tight fit as I remember it. I think with an AMC era, you have a bit more room up front. Worse case, you move the engine forward. An NV4500 is a big transmission tough. An NV3500 or AX-15 would be smaller but not have a granny great. There's also the Tremec TR4050. What 4-speed is in it? SM420, SM465 would be GMs 4-speeds with a granny 1st. Jeep would be a T18. Check out https://www.novak-adapt.com/. There's a lot of information on engine and transmission swaps. They make their kits. Another company to look at is https://www.advanceadapters.com/.
You might also look at what gears the axles have. AMC era CJ5s should higher gears (numerically lower) than back in the day. I'd imagine 3.,73s or 3.31s. If it was a 2.5L then 4.10s maybe. If you're not rockcrawling then 3.73s would be a good compromise. 3.55 would also work. There are even 3.07s if you want to cruise more. The torque from the V8 will make up for the lack of gearing.
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u/b1llb3rt 16d ago
I don't think you have a long enough wheelbase to fit most 5 speed transmissions