VH45DE with RB20 Trans

[tkmhkm]

I have a chance to get an RB20 trans for a great price of $200 and I'm wondering if it is possible to use this transmission instead of the z32. I could use all input and info that anyone can offer me. Thanks.

[Mettler]

The RB20 gearbox is made out of fragile glass, defenceless babies, and thin tissue paper.

Put these gearboxes behind anything with more torque than a small kitten and they don't last long.

A VH45 will reduce the internals to confetti before you even start it up.

Yeah, a bit of rhetoric, but not untrue. My friends used to use them behind turbo RB30s until they thoroughly wrecked a couple of them and decided to upgrade to the RB25DET box, which is similar/the same as the 300ZX TT box.

[Mettler]

This is what happens to RB20 gearboxes with small gusts of wind or if you happen to breathe in their general direction.

[Orphan]

I'm pretty sure the RB20 gearbox is basically nissans worst ever, it wouldn't surprise me if the mirca auto is better. I've known a few guys with R32's over the years and each went through at least 1-2 gear boxes on top of the original one and thats with not much more than factory power of like mettler said one Kitten haha. If you treat them nice with a 800cc matiz engine then maybe it will last a while. Mettlers analogies were on the mark.

[tkmhkm]

Well then here is my problem I've been searching the net and local ads and shops for a z32 transmission, not to complain Im not wanting to spend over $200 to get one used. I can get the original auto for the VH45DE for around $120, don't get me wrong I like an auto transmission for drag but this is my play car and not my dd so I would rather have an 5 speed behind the wheel. There are tons of 240's and 280z and 300z's at the local yard but the 240's five speeds are weak, the 280z's are all auto, and only two of the 300z's are 5 speed but non turbo. I have great fabrication skills so I looked through the yard for a T56 but they were already taken. Anyways thanks for your help with the RB20 trans I could not find anything on it online. Also I know that this is probably the wrong forum but to whoever is reading this I need a z32 transmission and a ecu to engine harness for a 1992 VH45De or just the blue plug in connector to the ecu with about 3" of wire still on it, some a-hole cut my ecu and part of the harness out of the car I pulled my motor from.

[Raxephon]

If the n/a 300z's at your local yard are z32 chassis, they will work just fine.

Skyline AWD GTR transmission might also be an option since they are basically internally the same as a Z32tt, except for the main case and the transfer case.

[tkmhkm]

Sorry bout that I meant to say 300zx is what is in the yard, the older 86-89 style with the straight six.

[PanzerAce]

There were no straight six 300ZXs. They were all VG30e/de/et/dett engines.

Realistically, if you can find a good four or five speed from an S30 chassis, that'll be more than enough to hold up to a stock VH. There are guys running them on almost 650whp Datsun. The issue they have with the drivelines is that they snap axles rather than trash the gear boxes.

The 300ZX trannies, as mentioned, will be fine from either a turbo or NA application, as they are the same internally.

Beyond that, if for some reason you can find a RB25 transmission, you could use that (though those aren't going to be very common).

And yah, run, don't walk, away from the RB20 transmission.

[Stinky]

I'd have to vote against the vg30e (Z31)/S13 trans. I shredded the teeth off of third gear and the car was barely over 300lbft. If you're plan on it lasting a while find a Z32 transmission or some variant of it.

[hannibal]

Isnt the RB20 transmission the same as KA and SR trannies?

I think Carl H was using a KA transmission with his VH...

[Carl H]

i have both a 400whp s14 with an rb 20 and standard 20 trans...it still shifts great and i daily drive the car.the vh car i have uses a ka gear box which is essensialy the same as the rb box and i flogged the crap out of it at a drift event and give it hell on the street and it still shifts perfectly.the 20 trans is not as weak as people make it out to be...just dont do hard launches on it and run drag slicks.

[Orphan]

Were there different generations of it at all? Because the two my friends R32 have gone through weren't abused that bad and lost it. For just driving around the RB20 trans would probably be fine but do a drag run or burn out and race and the VH would get the better of it pretty quick I would think.

As for tkmhkm over here (australia) you'd be lucky to find anything good for less than $700+ish don't even think about a RB25DET box over here they are $1400+ unless you find a good deal, its kinda stupid. Would be nice if there was a manual bolt on option for the VH, would make things sooo much easier. That said its not that hard to mill off the trans plate on the auto bellhousing then make one up for whatever trans you are using and weld it to the auto bell housing, just make sure the welds are good.

[Bart]

I wouldnt recomend it but then im using an RB20t GB, theyre a little stronger but go for RB25tGB if possible. The only reason i got the RB20t is because i havnt enlarged the trans tunnel but i will later and use the 25t GB

[tkmhkm]

Ok sorry about getting the 300z and 300zx mixed up its been a long day...Finally got my rebuilt ka running in my roommates car and the radiator cracked and almost overheated the motor......Time for an upgrade! But I don't mean to sound stupid here but an S30? what is the difference between an S30 and an old school Z. I read that the 88-89 model turbo old school Z's five speeds have the same internals as the Z32 transmission just different gear ratios.

[PanzerAce]

I'd have to vote against the vg30e (Z31)/S13 trans. I shredded the teeth off of third gear and the car was barely over 300lbft. If you're plan on it lasting a while find a Z32 transmission or some variant of it.

Huh, I thought the Z31 and Z32 trannies were the same. Live and learn.

Ok sorry about getting the 300z and 300zx mixed up its been a long day...Finally got my rebuilt ka running in my roommates car and the radiator cracked and almost overheated the motor......Time for an upgrade! But I don't mean to sound stupid here but an S30? what is the difference between an S30 and an old school Z. I read that the 88-89 model turbo old school Z's five speeds have the same internals as the Z32 transmission just different gear ratios.

There is no 300Z

S30 is the chassis code for the 1970-1978 240, 260, and 280Z cars. S130 is the chassis code for the 280ZX. Z31 and Z32 are the chassis for the 300ZX (The Z31 is a more angular looking one, similar in style to the S130). Z33 is the 350Z, and then Z34 is the 370Z.

As for the 88-89 models...I'm not sure. Those were Z31 VG30et cars, and according to stinky (who I have no reason to doubt right now), they didn't have the same bulletproof transmission that the Z32 series did.

I guess it all comes down to power goals and transmission availability. If you really can't find a Z32 VG transmission even in a junk yard, (and if machine shop time is cheap for you for an adapter plate), then I'd vote (in order of preference):RB255 speed from a L series Z car (S30 and S130s with the straight six)4 speed from a L series Z car

Though realistically, you'll probably save yourself a ton of headaches if you just shell out for a good VG transmission.

edit:Actually, if machine time is cheap for you, why not find a T56 or some other newish GM transmission? Those things will last all day and all night on almost any power you could expect to put through them and still have the rear wheels hooking up.

[Carl H]

correction to the z31 trans issue.the na cars used a version of the ka trans which is just about identical to the ka trans except in bellhousings...they are different.the 84-87 turbo models used t5 boxes and the 88-89 cars used a transmission that is identical to the z32 tt internally but has a different bellhousing and shifter style.

[tkmhkm]

Thanks Carl H, I thought that I read that same info somewhere. And in response to the T56 well trust me I looked for those in the yard too but again all out. The only transmission's that are on this list that are in the yard are the 5 speeds out of the non turbo L series. And to really get this topic on transmission's going let discuss the stock auto real quick, just out of curiosity has anyone thought about the stock auto for the VH45DE with a higher stall torque converter and a electronic shifter package added for either paddle shifters or slap shifter style?

[hannibal]

A few guys have used the VH auto in a swap. And others are using upgraded VH trannies in their Q. It'll work obviously...

The only paddle shifted Nissan I know of is a 240sx with an automatic KA. zerothread?id=179632

Like all manumatics, I dont consider this a substitue for a true manual. Its a novelty at best.

[PanzerAce]

The only transmission's that are on this list that are in the yard are the 5 speeds out of the non turbo L series.

Go for it I'd say. People are using those on 400+whp Zs as daily drivers all the time, and even the 600+whp guys are using the standard 5 speed boxes.

[Mettler]

You don't have to stick to Nissan gearboxes either.

The Toyota W57/W58 gearbox is known to be a fairly resilient gearboxe, often used behind 500HP V8 transplants.

The Toyota R154 is a super beast of a gearbox, tougher than the 300ZX & RB25DET boxes. My flatmate just upgraded to an R154 behind his Holden 308 V8 motor to complete the bulletproof setup.

To be honest, the R154 would be my preferred gearbox of choice.

[tkmhkm]

Ok guys here's an update.....The yard finally got some new cars in and I looked everything over, there are 2 mustangs with T-45 that can hold 325' LB, and there is an 84 300zx with a 5 speed and 2 81 280zx five speeds in the lot, I plan to go pull a transmission tomorrow so I need to know what everyone would recommend...Thanks to all and I will do and extensive write up on the transmission install...