Rb20det Rebuild Kit?

[rx-line]

Hey folks,

I am looking for a rebuild kit for the RB20det transmission. My current box has the synchros gone for second gear, leaks slightly and has a bearing noise from sitting for so long. I have a spare that seems to be sloppy and has been sitting for 3 years. Now before we get off track in the "Upgrade to Rb25 transmission" posts here is where I am at.

Rb25 Box

Pros:

• Strength 400ft/lbs??

Cons:

• Size (too large for rx-7 tunnel)
• Need new Prop shaft end
• Cost $900-$1000
• Unknown mileage & wear
• New clutch??

Rb20 Box

Pros:

• Already have two for gears to choose from
• Rebuild kit would cost less than $900??
• Already have stage 4 clutch and prop shaft
• Known wear and state of transmission after rebuild
• Increased strength/reliablility
• Still good for 300-350 ft/lbs

Cons:

• Not as much strength as Rb25 Box

So my question is where can I get an Rb20 transmission rebuild kit? If not can I use a KA or CA rebuild kit?

[GTSBoy]

Brand new RB25DET box available (here in Australia admittedly) for ~$3k.

I know what I would do.

And no, you probably can't get a "kit". What would be in that kit? Or more to the point, what would NOT be in that kit. Some people need 1 or 2 new synchros. Other people need 4. Some have bearings that are fine, others are all chewed up. Some need the selectors done, detents fixed up, any of a dozen other variables.

The correct thing to do (when rebuilding) is to take it apart, fish through the loose parts from the number of spare boxes you have (which may be any number from 0 to many) and then buy new bits from Nissan or other sources to make good all the bad bits. You can't know in advance what you need.

[turboedsloth]

^+1 to this. All the manuals that come through the shop here are a strip and quote job as every manual is different.

In saying that, you can get kits off ebay from the states, they are all the bearings and all synchros. Or give award diff and trans a ring

[rx-line]

In the V8 world the kits come in "master rebuild kits" or "partial Rebuild kits. Including everything from synchros, bearings, gasket, seals etc.

I have seen rebuild kits for the CA19 and KA. I was unsure if there was an aftermarket rb20 kit or if it is interchangeable with the KA and CA parts as the boxes are similar.

I know typically bearings + Syncrhos usually do not need replacement depending of course.

I would like to cover all ends if I am fishing through two boxes to create one proper one.

[rx-line]

^+1 to this. All the manuals that come through the shop here are a strip and quote job as every manual is different.

In saying that, you can get kits off ebay from the states, they are all the bearings and all synchros. Or give award diff and trans a ring

I am seeing no RB20 kits, do you mean KA or CA kits?

[turboedsloth]

Google FS5W71C rebuild kits. A few links come up

[turboedsloth]

I would buy parts locally though depending on where you are

[Hadouken]

Put rb25 in it

[rx-line]

Google FS5W71C rebuild kits. A few links come up

Awesome! Answered so many questions with just this code. Many nissan transmissions are alike i see.

[89CAL]

I got a kit from ATC in brisbane. Was just bearings and gaskets but they were also able to supply some of the synchros etc after i asked about them

Bearing kit was $300 or so? Cant really remember was quite a few years ago. I think it may have been less than that

[rx-line]

Kits for the FS5W71C are about $100.00 would need to review quality though. I shall try them 89Cal thanks. Maybe they can point out the differences

RX

[rx-line]

Kits are most definitely available. ATC quoted me $409 for bearings alone, they told me the rb20 uses the FS5W71E rather than the FS5W71C transmission. Other suppliers sell kits that are seemingly universal and fit both for much less.

RX

[turboedsloth]

The ATC kits usually come with all major bearings, needle rollers, seals, gaskets if available etc etc. They are a good quality kit

[89CAL]

ATC were very helpful and the kit was great. They also sorted out some of the other parts I needed

They got my business because of great customer service and reasonable pricing. 4 years on and not a problem with the gearbox

[rx-line]

Took the spare transmission off the engine and the transmission from the car. Both transmissions from the rb20det.

One is:

RB71c #1 - From car (Found a clutch fork broken on one side. I'm gonna swap second gear from the spare as it's good and get a replacement syncro.

RP71c #2. - Full working order, good bearings/minimal play, fair amount of wear on 1st 3rd and 5th

I noticed the gears are fairly soft with rounded tops from wear. Obviously not a bad thing.

Cheers,

[rx-line]

I have ordered

http://www.americanpowertrainwarehouse.com/fs5w71c-fs5w71e-f4w71e-nissan-manual-transmission-rebuild-kit-with-synchro-rings-fits-83-93-2wd/

We shall see the quality and fitment of the parts, I shall report back with findings so that others going through the same issues can see.

The quest bearings are made by nachi (fairly decent brand form my understanding). The only thing I noticed was that the transmission uses mostly sealed bearings and a roller bearing as well where as this kit replaces it with a ball bearing.

Any inputs on why this is?

RX,

[turboedsloth]

They are the same style of bearing used in your box, but they only supply the main bearings.

[rx-line]

Diagnosis:

The cast aluminum and brass impregnated shift fork had broken off on one side (glad it wasn't the cast iron one) between 1st and 2nd gear. The syncros and gear were quite beat up. The gear was replaced with the 2nd gear from the spare and the syncro form the kit was added. Obviously there was a fair bit of aluminum pieces throughout the trans.

Final judgement:

The kit's bearings all acted as replacements for what was in the transmission. However there were a lot of needle bearings separating the shaft from gears that the kit did not come with. We just used the best from both trannies.

I believe we ended up using the 2nd, 4th and 5th gear syncros while the other 1st and 2nd in the kit were for smaller gears.The new Nachi bearings seemed to be better in most circumstances besides one of the thrust type needle bearings on the shaft.

The only way to truly tell if we are successful is to test the unit in the car. Unfortunately it's snowing here and I have a Competition stage 3.5 clutch to replace after only 3k of driving!

[rx-line]

I will also add, that the machinist who had helped me with this mentioned that the gear sets are quite large and seem to be well made. Goes on to mention that they are bigger than even some chev transmissions.

The weak link would be the syncros / shift fork.