Overdrive transmission choices for AMC 401

[caionneach]

Situation: 1982 Jeep Cherokee Wide-Track restoration---

Components: Stock 258 cid engine and T-5 transmission;

purchased AMC 401 V8 (without intake and exhaust manifolds, carburetor, alternator, and a lot more ).

Problem: Choosing a transmission, preferably one with *overdrive* capability, to mate to the AMC 401 V8.

Options: NV4500 manual 5 speed (fifth gear is overdrive);
GM 700R4 automatic overdrive (fourth gear is overdrive).

Additional considerations: NV4500 adapts to 401 with a bellhousing kit and an adapter from Advance Adapters or Novak Conversions and mates to the stock NP208 transfer case via the 23 spline output shaft.

Not clear about the 700R4---> Novak Conversions lists a kit for the 304 and 360 engines, but not the 401. Novak Conversions has replied that I will need a flex plate for a 401 that they can take and modify that will then work with their adapter.

Both transmissions appear to be tough, truck transmissions when the 700R4 is beefed up for heavy duty and 4X4. NV4500 is heavy duty by design.

Both are comparable in price. Which to choose? Which is easiest to install? Which will provide better gas mileage?

Kenneth Smith
Monroe, Louisiana

[caionneach]

Many views, no help!

[jeepsr4ever]

I will post up a little later...have to ship a boat load of AMC parts....I also have been thinking on this and will let you in on pt#'s ect.

[caionneach]

You're a God-send!

[["Avatar-send" for you ACLU types]]

I'm inclined to choose the NV4500 just because there's no doubt about the adapters to make it work. A buddy of mine says I should install the 700R4 because it will make drinking coffee while driving during rush hour traffic a lot easier!

[Dusty]

thats how i drive and drink, left knee on steering wheel, enough movement to hit the clutch left hand for shifting and right hand for drinking the cold .... or hot .... and head tilted to the side talking ont he cell phone propped between shoulder and ear.

yes i am the CHP poster child of what not to do. my friend jim is doing a 700r4 into his 401 cherokee. i vote manual though, drove a t-176 360 power cherokee once loved it 5 spd would have been just that much more

[BRAD ARTHUR]

good question and both equally good trannys. please post your outcome along with cost of conversion. both could be kinda pricey from what i see?

[Atransman]

It really depends on what you plan on doing with the vehicle. If you plan on rock crawling go with the NV4500. The NV4500 has either a 6.34:1 or 5.61:1 first gear (depending on the transmission) and the 700 has a 3.06:1 first gear.

[jeepsr4ever]

Paul I will let you deal with this one as I am really busy here tonight

[pyagid]

It really depends on what you plan on doing with the vehicle. If you plan on rock crawling go with the NV4500. The NV4500 has either a 6.34:1 or 5.61:1 first gear (depending on the transmission) and the 700 has a 3.06:1 first gear.

I agree with this 100% but, with the auto dont you factor in the slippage of the Torque converter as well? which multiplies the gear ratio?


Also the 700r4 will take more power to run than the nv4500. I believe. I think i remember seeing that a th400 takes close to 40hp from the motor to operate

-Paul

[Dusty]

It really depends on what you plan on doing with the vehicle. If you plan on rock crawling go with the NV4500. The NV4500 has either a 6.34:1 or 5.61:1 first gear (depending on the transmission) and the 700 has a 3.06:1 first gear.

The downside to the 6.34:1 chevy nv4500 is it was only made for 2 years and 1st and reverse are not syncronized.

Depending on what route you go with adapters the dodge NV4500 uses a 9 1/4" long input that is 1 1/4" in diameter and the Chevy input is 7" long and 1 1/8" in diameter. on your long wheel base vehicle this doesnt mean much but it is something to keep in mind as the dodge input is significantly stronger.

also the dodge tranny's up to 97 or 98 in gas powered vehicles had a 23 spline output. The dodge diesel's use a large 29 spline The chevy's use a 32 spline output.

The later 96 and up chevy nv4500's use the same gear ratio as the dodges but require a input bearing retainer with a collar as they are designed w/o IIRC. as it was not a big problem. also the early chevy nv4500's have a different bolt pattern for marrying to the bellhousing than the later ones. the later ones share the same pattern as the dodges.

I vote for the nv4500 just be aware that with a dodge input you will have to order a special clutch with a different hub to match. easily done just specify. and if you have the linkage and bellhousing i would do a dodge NV4500 matched to a T176 or T18 bellhousing using your existing linkage etc. If you dont have the linkage i would get the AA bellhousing and either the chevy or dodge nv4500 and then you will have to put the chevy input into the dodge and machine down the input collar. and run a hydraulic clutch. the benifit here is a t-18 clutch for a J truck works

i changed the output in my dodge nv4500 from the big 29 spline to a 23 spline output this also requires a different OD gear both parts were not that expensive and eaily had through inland truck parts up in missoula mt.

As to the 700R4 Paul is right the torque converter does compound the ratio and the 700R4 has a low 1st gear to begin with lower than some other auto's out there. and i believe the number is 20%-25% of the power is lost to parasitic drag correct me if im wrong here. but it is a nice easyt o come by setup. the build up that is necessary to make it last with the torque of the 401 is expensive but well worth the investment if you choose to go that route. dont trust most run of the mill kits nor shops. the 401 shreds these things just like a 454 does when they arent done right