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I have been reading as many 5spd posts as I can but am still having trouble making a decision. As of right now I have the 2F adapted to a SM420. Very low, very nice for crawling around, but now my rig is becoming more of a daily driver and I could use an overdrive gear.

I have looked into the H55, the NV4500, and some others, and would like the opinions of some knowledgeable people about which to go with. Since I already have a GM tranny in there would it be easier and more practical to go with another GM 5spd, or would it be better to go back to a toyota unit?

Are there any other recommendations? Which is the best place (i.e. cheapest) to get either tranny?

Thanks for the input.
 
You are going to need a different flywheel housing to make a NV4500 work with your GM engine..IIRC.


Call around a few wrecking yards, do some searching on line/ebay/etc...you will find a tranny.


If you have not spent any time at AA's site, reading through the info they have out there on this swap, I would do so, as they cover many of your questions about what year truck, 2wd/wd, etc...



I would not go with a Toyota five speed tranny, unless you find one from MAF or SOR that already has a tcase on it, as they use a split case instead of a one piece like what you have already behind the 420...and then you are going to need to address the parking brake issue, as the split case does not commonly have a parking brake on it in North America....you may find a used combo from one of these parts houses or someplace else that has one on it...you will need a four speed Toytoa flywheel housing, and then need to modify it as has been talked about in the other threads on this...hit the FAQ on this if you missed it..



As I stated in your other thread on this very topic, I would go with the NV500 over the Toyota tranny for your application.


Good luck!


-Steve
 
Poser said:
As I stated in your other thread on this very topic, I would go with the NV500 over the Toyota tranny for your application.


Good luck!


-Steve

{Quote sniped}

Yeah crunched some #'s using following inputs; r&p 4.11/34.5 tire/65mph:

sm-420 w/ 1:1 = 2602 rpm
h55f w/.845:1 = 2199 rpm
Nv 4500 w/.73 = 1899 rpm
700r4 w/.70 = 1821 rpm

Swapping considerations so far:
H55f would need clutch housing adapter/throw out bearing/clutch
nv 4500 clutch housing adapter(external slave on drives side)/adapter to transfer via 'spud' shaft. + from the reading looks like something 'balancer' is removed from the factory nv-4500 design?
Between these two think the h55 would be the shorter?

700r would need adapter to transfer, and drive line issues both in length and clearance of tranny pan. And nobody seems to use the Downey 1" adapter, but there is maybe that Sunray adapter, but that might mean transfer case would have to be swapped for jeep type which would open up the rear axle can of worms.
 
Poser said:
I would not go with a Toyota five speed tranny, unless you find one from MAF or SOR that already has a tcase on it, as they use a split case instead of a one piece like what you have already behind the 420...you will need a four speed Toytoa flywheel housing, and then need to modify it as has been talked about in the other threads on this...

-Steve

Steve, I'm confused! What modification needs to be done to the Toyota 4 speed bellhousing? When I swapped in my H55 I did absolutely NOTHING to the bellhousing because both were EXACTLY the same. Mind you this was for a 3B diesel but I can't see that make a difference.
 
When I researched mine I ended up going H55. It ended up being a trade off, I gave up a little overdrive for some extra driveline length. I think the 4500 is 18-19" long with the adapter in place. The H55 is around 14" long (3' longer than H42 IIRC). The 4500 shift tower sits way back on the tranny (based on pictures), the H55 isn't quite so far (depending on which shift tower you have) With the H55 I was going V-8 at the same time so a few extra RPM was of minimal concern. The shift tower is in almost the same place as my 4spd shifter was. I was lucky when I received my tranny/transfer it already had a e-brake set-up on it. Now that I have it in the chassis I am happy with my choice. Of course this may change when I finally get to drive it. Another book that may help is the NV4500 instruction manual from AA. If your interested you can have mine.
 
Last edited:
Hi All:

I'm assuming your rig has a 2F. The easiest/cheapest way would be for you to swap-in 3.7 ratio diffs for the 4.11 ratio you have now. You might find the first gear of the SM420 a bit more usable on the street!

Any overdrive transmission swap is going to be expensive and involved.

Good luck!

Alan
Seattle
 
Poser said:
You are going to need a different flywheel housing to make a NV4500 work with your GM engine..IIRC.
-Steve

:confused:

vt78cruiser said:
As of right now I have the 2F adapted to a SM420...

:confused: :confused: :confused:

VT,

Are you staying with the 2F?

If so, I would go H55F.

The H55 is shorter than the NV4500. Plus I have heard (empahsis on heard only) that the 2F doesn't have the huevos to push 5th in the 4500. So if you are keeping the longer 2F, the shorter H55 would be good.

E-brake, I think the best option would be a late model 40 rear axle housing to put brake out at wheels. Or build a disc/caliper to run off the split case...
 
I am still torn between both choices as I can argue either way. Does anyone have any experience with the Man-A-Fre rebuilt or used H55's? I have been looking on the web and they are priced well below SOR. I would try and stick with the 2F so I see the H55 as the best option at the moment, unless the price becomes too outrageous.
 
I went the H55 route and then found out that 5th gear is prone to going out. After about 2 years my 5th went south and now I'm wishing I went with the NV4500, or bought abrand new H55.
 
PabloCruise said:
I'd go C-Dan, brand new H55 in the box for spanky prices...

Find a used split case and go to town.

Label me ignorant, but who is Dan? Does he have a website? Thanks for all the advice so far guys and gals.
 
Cruiser Dan is your new best friend...

He works parts at American Toyota in ABQ, NM.

Sweet dicounts to TLCA and/or MUD folks (do you have to have a star?)

Free shipping on orders over $100, but prob not on something as heavy as a h55.

See American Toyota's banner ad, or search the member list...
 
yldbill said:
I went the H55 route and then found out that 5th gear is prone to going out. After about 2 years my 5th went south and now I'm wishing I went with the NV4500, or bought abrand new H55.

How many miles?

Couple of the truck I deal with on a regular basis:
My FJ40 (new H55F, ~30k, 4 years, mosty wheeling (or heading there), no probs)
Darrells 45 (used H55F mated to 2HT, ~60k in his rig, 5th gear noise, some play)
Mike D's 40 (used H55F, ~50k in his rig, no problems)
Greg's 40 (used H55F, ~75k in his rig?, no problems, DD)
Peter's 60 (used H55F, ~20k in his rig, no problems, DD)

Seems the used units are hit an miss, not worth the risk IMHO. All of the brand new OEM ones I have dealt with have been flawlees for 4+ years, and since I did a new one in my FJ40 4 years ago, I won't do a used one again, not worth it by any means.

Hope that helps... :D
 

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