DIY tranny rebuild

[thouchin]

I have read many post that recommend a qualified NSX mech do a tranny rebuild. I'm considering buying a 91 NSX that has a tick from the tranny which would probably be a bearing.

I've rebuilt a CRX, Integra and a Toyota Truck tranny so I was thinking I would do it myself. I can't see what is special about the NSX, am I missing something?

T.J.

 

[sjs]

... am I missing something?

T.J.

Probably not. The same basic principals will apply so you will need the right tools and general knowledge of how they work. If you haven't done one with multi-cone syncros you may see something a bit different, but I can't imagine that there are any radical differences. Not that I've had one apart myself, but from what I know in general and what I've seen in the manual I'd expect you can do it.

Larry B., have you been inside one?

Hey, I see you are in Peoria. Ever come to the St. Louis area?

 

[Yellow Rose]

Regarding the "tick" sound being a bearing, I recently discovered two bad bearings and the noise they were making was more like a "whirl" or a "growl". To me, a “tick” sound would be more indicative of a bad gear.

I have been inside domestic manual transmissions and my NSX transmission twice. The NSX transmission is by far more complicated. Bearings have to pressed off and on, there is an internal pump and dual synchro cones on 2nd gear. The tech that recently rebuilt my transmission commented that the NSX manual transmission is by far the most difficult of any Honda / Acura product that he has worked on.

 

[thouchin]

Sjs,
Yeah I live in STL about 6 years ago (St. Charles) and my parents are still there.

You are right, I've not delt with dual syncros or a pump yet. I plan to buy the manual and so far Helm has had all the info I needed ( along with lots of digicam pics ).

BTW, how do I find out about get togethers in St. Louis?

T.J.

 

[Larry Bastanza]

sjs,

Impatiently, no. I have been waiting since early December for the special tools I need. I have a snap ring 5 speed that I want to rebuild as a swap unit.

I agree the dual cone syncro is additional compared to most, but the basic design between it and a manual Accord is identical, right down to the snapring. When you compare these two transmissions in the service manuals it's like a "double take".

I think if you know how to use a press, have the proper press jigs, and are OK with accurate measurements (including having the tools) for gear play, end play, etc, It would be the same as any manual trans for the "first time". By no means am I implying it is trivial or easy, and I would not attempt this from the perspective "Gee Boss, I always wanted to fix a transmission?!?!".

But... If you are experienced with manual transmissions, I think seeking the right advise from the more experienced folks in the community would make it easier. There has been at least one pictorial write up from Dave in BRLA (?).

I recall MB mentioning about 80 rebuilds was his count, I will surely try to have a chat with him prior to "diving in".

T.J.,

From you comment, I think you are NOT "missing something".

Good Luck, if you decide to do it, keep us posted!

LarryB

 

[sjs]

...BTW, how do I find out about get togethers in St. Louis?

T.J., we don't get together very often, but when we do we communicate by email or a seldom used Yahoo group. Send me an email and I'll add you to my list then circulate to others.

Do you have access to facilities for serious service like the tranny, or just working on stands at home?

 

[thouchin]

No lifts or anything, I work out of my garage

LarryB,
I'm curious what special tools you need?

 

[nsxtasy]

T.J., we don't get together very often, but when we do we communicate by email or a seldom used Yahoo group.

St. Louis area members of the NSX Club are all notified of Midwest Region club events, and notices are also posted in the Midwest regional forum here on NSXprime.

Watch for more details about our upcoming event in Northern Indiana April 3-4. Hope you can make it.

 

[sjs]

St. Louis area members of the NSX Club are all notified of Midwest Region club events, and notices are also posted in the Midwest regional forum here on NSXprime...

True, and we appreciate it, but I've never made the relatively long trip for one and I don't think the other Gateway guys do either. But that doesn't keep me from being a member!

 

[sjs]

No lifts or anything, I work out of my garage

LarryB,
I'm curious what special tools you need?

It's late on the East coast. Larry must be asleep.

Besides the usual feeler gauges, micrometer, gear pullers, press, snap ring pliers, punches, dial indicator, etc. that you used on other trannys, there are a couple special tools for setting the mainshaft end play during assembly. They saw fit o make special tools for the task, and reading the manual I’m not sure I’d want to tackle it without them. They are part numbers 07GAJ-PG20110 and 07GAJ-PG20130 but is sounds like Larry has been waiting for them.

 

[daveh]

hey there I wouldn't let doin' a tranny disuade you from buying the car .Like most thing's honda they really are very basic.I've probably done 8-10 snap rings and just did an '03 for a 1-2 grind they really are basic.Like the other guys say you do need to set up the endplay and preload (diff) right for the long haul,but there's onlt a couple of spots that you can easily screw up .I did a case half once and the bushing that holds the 5-R shifts shaft and detente in place stayed in the old case half.It usually stays on the shaft!!!!! I had that box in and out 3 times in 1 day all for a simple oversight.just take your time and it's easy.There's plenty of people here to help you .Buy the damn car.Dave H

 

[Larry Bastanza]

Good Morning LOL.......................

Sjs is correct, these are the tools, also I ordered 07MAJ-PR90100 for the differential to properly set the preload on the diff bearings, since this is required for the trans case swap.

These tools can also be used to check your diff break away torque by locking one side in a vise, if you have the diff on the bench.

HTH,
LarryB

 

[Eddy]

more tricks than precedures

One you have opens a manual transmission, they are all the same.. Mainshaft, countershaft, synchros, gears, shift forks, shift mechanisms, diff.. that's about it.

On these transmissions (Hondas transverse) the tricks are probably more useful than procedures since the service manual does a good job telling you what to do.

-getting the snap ring open; a common one for first timer if you forget and try to open the casing
-opening the Hondabond sealed case can be a little difficult with bare hands; look for an edge in one area of the transmission that you can pry with a pry bar, it will crack the seal and the rest is cake by hand
-closing the transmission; the select/shift mechanism shaft tends to sit slightly off and makes closing the casing a hit and miss deal so focus on that if the casing won't close completely; also remember the selector arm
-never force a transmission open or close; you will regret it and your wallet will regret it even more when you see that crack on the casing
-you don't need all those weird press attachments for the bearings; just find some nicely cut tubings and they will work well
-when pressing always think where the force will go; bearings don't like to have 12 tons on their balls (literally) and synchros for sure can't stand that
-having a good vise and the proper attachment for working on the diff is nice; also for the countershaft as its got a nut on top that takes some arm power
-and most of all just remember to oil everything that moves, keep things clean and torque everything down properly; be detail oriented

Unless you have a really trashed up transmission, most parts will be in spec and the most you would have to replace would be the bearings and the synchros. Honda has made rebuilding NSX transmission really affordable that they sell individual synchro cones (instead of synchro sleeve sets on other Hondas) and bearings. So just replace the ones out of spec.

So go on and have fun.

Eddy

 

[Larry Bastanza]

Eddy,

Thanks for those tips, really great. I ordered the 3 tools above thinking they were really the only OEM tools "required". Once the trans is open I will be off to home depot for some pipe with the proper ID/OD for press operations. I have a great machinist that will turn the ends flat as I need it.

One trick I learned from rebuilding many porsche manual transmissions, in regard to that large nut, is if you remove the shift mechanism, you can actually put the trans in two gears at the same time, like 2nd and 4th. With the shafts still in the lower case they will be locked in place, then you can loosen and torque the big nut, which is LEFT HAND THREAD.

Thanks again,
LarryB

 

[Eddy]

great idea on locking the gears!

Never thought of that. Good experience to share!! When I used to work on smaller B16/B18 Honda transmissions, the shafts don't sit too firmly without the top housing so I always have to vise the countershaft with wood or plastic. And I never thought of putting gears in without the forks to lock the gears. I will try adding a nylon strap around the gears to make them stay put after they are locked to work on that nut!

Eddy

 

[DutchBlackNsx]

One trick I learned from rebuilding many porsche manual transmissions, in regard to that large nut, is if you remove the shift mechanism, you can actually put the trans in two gears at the same time, like 2nd and 4th. With the shafts still in the lower case they will be locked in place, then you can loosen and torque the big nut.

Hey, good tip Larry.
Stops you from putting that countershaft in a vice, where you never can be sure if it will be damaged.


Mich

 

[Larry Bastanza]

Good idea about the nylon strap. An alternative, since we have an abundance of "bad cases", would be to get an old case half and with a band saw take a slice out of it which has the web for the two bearing holes. Cut an access hole for the wrench to get the nut off and you have a jig that will slip on and off easily to hold the shafts together. Even a bad snapring case is perfect for this.

In the Porsche trans you needed a jig to do this since you had to actually set the shift folk positions, they were not indexed, so it was a required special tool. Instead of purchasing the tool, I cut a case this way. Always worked for me


HTH,
LarryB