GLHS

Was going to swap for a 4500 but now have other ideas.
Rundown of the gear ratios.
Getrag.......1st; 5.53, 2nd; 3.02, 3rd; 1.60, 4th; 1.00, 5th; .77,...............reverse; 5.03.....190 lbs.
NV4500......1st; 5.61, 2nd; 3.04, 3rd; 1.67, 4th; 1.00, 5th; .74,...............reverse; 5.61.....190 lbs
NV5600......1st; 5.63, 2nd; 3.38, 3rd; 2.04, 4th; 1.39, 5th; 1.00, 6th; .73, reverse; 5.63....300+lbs?
G56 05-07..1st; 6.29, 2nd; 3.48, 3rd; 2.10, 4th; 1.38, 5th; 1.00, 6th; .79, reverse; 5.74.....240 lbs?
G56 07.5+..1st; 5.94, 2nd; 3.28, 3rd; 1.98, 4th; 1.30, 5th; 1.00, 6th; .74, reverse; 5.42.....240 lbs?
ZF6...........1st; 5.78, 2nd; 3.30, 3rd; 2.10, 4th; 1.31, 5th; 1.00, 6th; .72, reverse?......... weight??

I have a 4500 from an 02 that needs rebuilt and with a 1-3/8 input and cast iron housing would cost about $1600-$1800 plus the Advance Adapters bell housing and a clutch for the 1-3/8 input. Higher overdrive equates to about 100 rpm less at 75 mph but for racing 2nd to 3rd shift might still be a problem.
Early G56 has crummy .79 overdrive but are more plentiful.
Later G56 costs $3000 to rebuild + other conversion parts. Is 2nd to 3rd is straight opposite from each other? I think so. Have yet to drive one.
ZF6; not sure if the ratios are correct and/or if they are the same between Chevy and Ford. The higher overdrive would be nice. They can be rebuilt for $1600. Would require a $900 bellhousing adapter from Destroked.com. Transfer case coupler would have to be custom.
NV5600 is heavier and slower to shift than the others. Expensive to rebuild; not an option.
Anyone else have thoughts or ideas on these swaps?
Is a ZF6 swap possible?

Crossy's son

They make the adapters to go from Cummins-ZF6, However i'm not sure about hooking it up to your transfercase, because an NP205 never came behind a ZF6 and i don't know the spline output on either ford or GM. Theres a whole section on the ZF-6 on www.dieselplace.com forum...they know alot.

i did some investigating and it seems the GM ZF-6 (S6-650) has a 32 spline output shaft. However some versions can be had with a 29 spline output which is what you want! http://www.performancetrucks.net/for.../t-404105.html < He says he has a 29 spline ZF-6 because he had a custom T-case input made so it would hook into his ZF-6 29 spline...(Yea i know its chevy gasser stuff but still good read)

I'd try and steer away from ZF6's with what you're doing... Duramax guys with a programmer/turbo/injectors BLOW them apart, but they make upgrade parts. http://www.dieselplace.com/forum/sho...hlight=carnage, but they make aftermarket. And at fall brawl diesel dyno even about 2 years ago a 7.3 powerstroke w/ZF-6 BLEW the trans apart on the dyno, the guy had to be trailered home....i was there and i heard loud boom and clanking..JMO.

All the transmissions you listed, (besides the getrag) BD makes a "short throw shifter" kit for. Like $200 ...I've heard they help SHIFTING alot, Probably be good for bangin gears . Including the 1998 + NV4500 http://www.dieselperformance.com/ind...duct/index/31P

G56- numerically higher overdrive in the early years, many complaints so they changed it to .74 when the 6.7L came out. Its also a Benz Tranny and it was basicly an in house dodge trans, but expensive to rebuild (parts$$). Whole discussion thread NV5600 vs. G56 << Link

NV5600 pattern- Its also cast-iron case

G56 pattern- Is the same thing as NV5600 EXCEPT the G56 has reverse to the LEFT and down of 2nd gear, Otherwise standard 6spd pattern, Its an aluminum case trans.

IMO, I'd go with the NV4500 since you already have one and its been done numerous times, and it will go right up to your NP205 T-case. And there is companies that make GETRAG to NV4500 conv. kits..... And BD makes a short throw kit for it and that'd probably be pretty fun

I hope you get something from that...
Brandon

NO_SPRK

Eaton-fuller 10-speed road ranger! Divorced NP205 aNd SAE-2 housIng

Caver Dave

Not to discount CS's info, BUT

I know 3-4 guys with 2nd-3rd Gens (all running 500+hp & tow VERY heavy) that have obliterated numerous NV & G trannys. They've all gone to ZF6's (+ destroked adapters) for more trouble free miles than all the NVs & Gs combined...

Having said that, I will make the push to a rower in the next year and not really thrilled by *ANY* of them...

Exekiel69

I'll be watching this thread since this is the same dilemma I'm in right now. I can rebuild the getrag every other weekend for cheap (and not so cheap anyway), then the nv4500 is good but has some trouble if You want to pull heavy often then the others are so out of My budged I don't even consider them. A medium duty is good but then I need to change the read to make the first gears useful at all.

jimbo486

i like my nv5600. seems to shift fast enough for me. i don't try to slam it in gear either. i'm nice to it, and it's nice to me. never heard that they're expensive to rebuild though. what's the reason behind that? i would think a standard trans would be cheaper/easier to rebuild vs. an auto.

Riflemanusmc

Discontinued.........AKA, from now on ALL 5600 parts are made gold....

crewcabxlt

if you want to run fast 1/4s go nv4500

NO_SPRK

I was reading a thread about a 2nd gen nv5600 truck swapping to a medium duty trans because he was on his 4th trans. It was amazing how many people replied talking about their trucks and being on 2nd and third trans. 4500 guys too were complaning about them. My friend has a ford cummins. His truck has a ZF5 gas tranny behind his 450hp P-pump engine. He has a southbend clutch, does 2nd and 3rd gear burnouts and tows heavy with it. He loves it. I don't follow the power-jokes but I haven't heard of many trans failures and they don't make the snapping torque cummins do

GLHS

If Crossy has the shift pattern right for the G56, it is a lot less appealing now.
Have also heard the Ford ZFs have an oil pump for lubrication whereas the GMs do not. Do Fords fail less often?

Crossy your only fifteen? You learn faster or listen better than a lot of guys out there to know what you do about 1st gens already. Continue learning and gaining knowledge as best you can; good or bad.

Thanks for the input. Keep them coming.

NO_SPRK

yeah well the fords engines fail before the trans can hahaha . seriously anything after a 7.3 is JUNK

GLHS

A little more info.
From what I understand the GM ZF6 has the 29 spline output but, it is very rare and the stock bellhousing does not fit over a Cummins flywheel. If it can be found, would need a Ford bellhousing.

The ZF6 in Fords have a 24 spline output if it came from a 7.3 and a 34 spline output behind the 6 liter.

Purplezr2

No, brandon is fifteen, I would imagine Crossy is 35-40 years old, maybe older.

rich

i tow heavy and didnt have a problem with the nv45 once i fixed a few problems like 5th gear, upgraded input shaft, added trans coolers and ran extra quart of oil to it

Crossy's son

He's 50

People call me crossy all the time, my dad's never on here so its ok