Would like transmission swap ideas and donor vehicles

[cuban11182]

I'm headed to my fathers house in PA at the end of the month. I would really like to find an NV4500, but being that most people looking for them I'm not sure I'll be able to find one in a junk yard up there. In any case I'd like to eventually swap in a 4bt, but in the case that I can't find one, what is an alternative 5 speed that would be a good substitute?

Thanks.

 

[HackFabrication]

In any case I'd like to eventually swap in a 4bt, but in the case that I can't find one, what is an alternative 5 speed that would be a good substitute?

Alternative Overdrive 5spd that will handle the torque from a diesel? None that I know of. Maybe a ZF, but I have no idea what sort of adapters that would take. You are the the right track with the NV4500. They are available, ya just gotta pay the price.

 

[Saddle Tramp]

The whole NV4500 combo is pretty long but here is some information from Novak.

http://www.novak-adapt.com/knowledge/nv4500.htm

 

[ThisGuyUKnow]

I'm going to just give an opinion here so feel free to take it or leave it....

If I remember your thread where you showed us your newly acquired cj not long ago, it was a rust free clean almost original, relatively unmolested CJ. If I had made such a score I think I would try to keep it fairly stock because rust free original cjs are getting rarer by the day. The fact that you are taking about an nv4550 indicates to me that you probably have more very serious modifications planned down the road besides that diesel. It's your jeep and you can do with it as you want but just remember some stuff can't be undone.

For a five speed upgrade you will save alot of money by going with an ax15 or nv3550. Both are natively compatible bellhousing patterns. if you don't want to re work your pedal assembly to hydraulic, there are adapter kits that use a t176 bellhousing to make them work with your manual linkage. The adapter kits for the d300 are fairly cheap. If you use the 4.0 fly wheel you set yourself up for success should you choose to go mpfi on the six cylinder later. And either transmission is very strong and have good service life in heavy duty applications.

Edit:
This is from the Novak information page on the nv4500:
NV4500 Mythology

When the NV4500 was released in the mid-nineties, the 4wd aftermarket and magazines latched on quickly. It was uncritically ballied as the silver bullet and cure-all to any 4wd powertrain problem. Phrases like "Ultimate 4wd Transmission" have been common.

As time and trial have shaken things down, the NV4500 trend is now seen by serious 4wd powertrain afficionados as a prime example of herd instinct. Many individuals have been left unsatisfied with the expense of their transmission investment vs. its benefits. The drawbacks have been:

Gearing: The NV4500 has an initially attractive overdrive gear, but with a low gear of only 5.6:1 (most units) and a gear span of 6.07, its position against the heavy-duty four speeds (SM465, T18, SM420 or NP435) is inferior. Choosing the right axle ratio and tire size in conjunction with the right transmission is a smarter strategy than using overdrive as a patch to the system.

Size: The length of the transmission, even in its shortest renditions, is too long for many Jeeps, especially those with suspension lifts. The result is u-joint vibration and weakness. The transmission also often requires serious surgery of the body's tunnel to gain back ground clearance.

Expense: The initial flurry to get a 4500 drove up salvage prices that have never really ratcheted back down. New units have been available ranging from $2300. - $2600. Parts availability and expense are surprisingly discouraging in addition to frequent year-to-year parts changes. Expense for NVG to build these transmissions is significant. Overdrive adds serious complications to any gearboxes design and manufacturing.

Strength: Weaknesses in the transmission mainshaft clutch splines and their mating hubs (usually 4th & 5th gears) from fatigue and wear are prominent. The HD four-speeds exhibit consistently better strength & wear characteristics.

Adaptability: Expenses and complications in adapting to either the engine or the transfer case is high. Clutch linkages also prove challenging.

There are too many NV4500's in Jeeps due to an artificial push by aftermarket profiteers and hungry magazine writers looking for a quick story. Actual research and critical analysis by the thoughtful Jeep builder will more often yield the conclusion that a heavy-duty, four-speed transmission (if not an automatic) will produce better on-road & off-road results with significantly less expense.

 

[Saddle Tramp]

Well Said!

 

[mtnwhlr]

Well Said!

 

[cuban11182]

Ok, Ok, LOL. I'm going to keep the stock 258 and T5. I'll rebuild both of them, and do the 4.0 head. I like the idea of having a bullet proof engine. I'm going to be easy on the T5, and don't plan on going much higher than 31 tires.

Thanks again.

 

[HackFabrication]

I'm going to be easy on the T5, and don't plan on going much higher than 31 tires.

Geared appropriately, driven sanely, and maintained correctly the T5 should pose you no troubles. Start trying to make it do things it was not intended to do will destroy the internals.

 

[cuban11182]

I don't think I'm ever going to beat on this thing. Knowing how much time and money I'm going to invest, and being that it's getting rarer to find a CJ in this condition would make me upset. Besides I have a built truck if I want to go fast or do some crazy offroading (which I don't do normally at all).

 

[ThisGuyUKnow]

I don't think I'm ever going to beat on this thing.

Lol then why was an nv4500 on the table at all?

 

[cuban11182]

Lol then why was an nv4500 on the table at all?

I was really thinking about a 4BT, and then off course completing a TON of power mods and destroying the drivetrain!

In honestly I thought that the T5 couldn't handle the 4BT. I may eventually do the diesel swap, but I'd have to get a good deal.

 

[HackFabrication]

31 inch tires + 3.73 gearing + .72 5th gear = 2038 rpm @ 70 mph

My 4.3 V6, 4L60E auto OD blazer is right about at that with 235/75R15 tires (29") with a slightly taller .70 OD, 3.42 gearing, I'm 70 mph @ 1950 rpm

 

[HackFabrication]

My 76 CJ5 with its 5.0L Ford Racing engine, T18 transmission, 4.56 gearing and 32" tires is screaming at 70 mph @ 2830 rpm.

 

[Neuner]

I don't think I'm ever going to beat on this thing.

Was wondering how you were going to be able to do that in Corpus

If it is in that nice of condition, just please be careful with that salty air. Did you find it locally?

 

[cuban11182]

Was wondering how you were going to be able to do that in Corpus

If it is in that nice of condition, just please be careful with that salty air. Did you find it locally?

I normally drive my truck if I go to the beach or anything like that. Nissan Titan's are a dime a dozed. Although the roads do suck, I normally drive the jeep back and forth from work from downtown CC to next to the Lexington.

I've already gone underneath with wire brushes and some Rustoleum rust coverter. I know it isn't the greatest, but the plan is to do a frame off preservation once I move in a year or so. It was found locally, but it originally was in the Valley and towed behind an old couples RV.

 

[ThisGuyUKnow]

I normally drive my truck if I go to the beach or anything like that. Nissan Titan's are a dime a dozed. Although the roads do suck, I normally drive the jeep back and forth from work from downtown CC to next to the Lexington.

I've already gone underneath with wire brushes and some Rustoleum rust coverter. I know it isn't the greatest, but the plan is to do a frame off preservation once I move in a year or so. It was found locally, but it originally was in the Valley and towed behind an old couples RV.

RV Tow behind CJs are the ticket. When i was in Iraq I had an opportunity to purchase one for like 6k, I wish I had bought it. It was so immaculate it had all the original warning stickers and looked like a new car.

 

[Neuner]

It was found locally, but it originally was in the Valley and towed behind an old couples RV.

Nice find!! Can't beat getting it from the Valley area away from the surf.

Guess you have pics in the other thread?

I'm assuming if you've studied the 4BT then you know it has a narrow sweet spot on the RPM range. Just make sure that if you go that route that you have your drive train inline with the right ratios to keep in that small range.

I'm looking to go the diesel route as well but with a smaller, lighter turbo version. Would be nice if I could do that this fall.

 

[cuban11182]

I'm still very unsure as to what I"m going to do. I do like the 258 though. Plus if I put enough into it in the stock configuration I'd be a fool to part with it.

Right now I'm trying to find out if the Offy intake with a Holley 390 will have clearance issues with power brakes.

Oh, and yes. I have pictures in my other thread.

 

[Peanut Butter]

I was really thinking about a 4BT, and then off course completing a TON of power mods and destroying the drivetrain!

In honestly I thought that the T5 couldn't handle the 4BT. I may eventually do the diesel swap, but I'd have to get a good deal.

Look at a Chevy 4bt and hook a TH400 tp it. If I read correctly, this bolts up direct with no adapter. The TH400 was found in CJ7s. Just a thought. Rod

 

[ThisGuyUKnow]

If you really want to wake up that 258 you can look at a t50 head. You can run that with the carb out you can continue on to mpfi.

If you want a good 5 speed the ax15 out nv3550. To replace that 258, I'd go that route over rebuilding a t5. Although the t5 can be good with the correct gearing to tire size, the wrangler trannies are stronger all around and not as sensitive. Plus it will give you the opportunity to tinker and build(which you are obviously dying to do and I don't blame ya) while keeping it looking original.