1G Manual trans recommendations

[Anfurnyy]

Looking for recommendations on rebuilding/fixing my trans.

So my 93 trans has been having issues grinding into 2nd and 3rd and decided to pull it apart to check it out.

It was "rebuilt" about 10 years ago by a local shop. Previous owner drove it for maybe 800 miles and then parked it due to jumped timing. That's when I bought the car.

Upon disassembly I found some concerning things:
*5th gear hub has some chunks taken out of it.
*Looks like someone hammered a screwdriver under 5th gear to try to get it off.
*There's RTV stuck in the slider/synchro keys and springs, as well as under the bearing races of the bearing plate AND inside the oil galley holes of the intermediate shaft.
* Shift forks and sliders seem to have a bit of wear where they contact each other.

I know I'll need at the very least a 5th gear hub and tapered bearings, and likely shims however 5th gear hubs seem absolutely impossible to find.
I'm also worried about finding and correctly shimming for preload if I continue to pull the gears off to check the 2nd and 3rd synchros.

The car is pretty built and I plan on making a bit of power, over 600whp and dragging the car when it's done. It's a street/strip car.

Anyone got any advice how I should proceed?

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[bastarddsm]

Find an earlier core, and save that one for a rainy day.

 

[XC92]

Aren't stock DSM manuals trans not really mean to handle this sort of power, maybe up to 400-500HP or so, at which point you have to get a beefier trans or switch to dogteeth gears?

In any case, I rebuilt my '92 AWD trans a couple of years ago and it appears to have held up well, just a tiny leak that I'll finally get around to dealing with this year (I probably didn't RTV it properly, or maybe there's a nick or ding in one of the mating surfaces that needs to be restored somehow).

Took forever as it was my first attempt and I was learning as I went plus had to place multiple orders, first for the parts that needed to be replaced, then for the proper shims. But it's definitely doable.

I got most parts from Amayama, although you can get most in the US for a somewhat higher price. If you can't find what you need here, try them, although shipping is slow as it's either from Japan or UAE.

But, definitely first check if the trans can handle that sort of power.

 

[Anfurnyy]

Aren't stock DSM manuals trans not really mean to handle this sort of power, maybe up to 400-500HP or so, at which point you have to get a beefier trans or switch to dogteeth gears?

In any case, I rebuilt my '92 AWD trans a couple of years ago and it appears to have held up well, just a tiny leak that I'll finally get around to dealing with this year (I probably didn't RTV it properly, or maybe there's a nick or ding in one of the mating surfaces that needs to be restored somehow).

Took forever as it was my first attempt and I was learning as I went plus had to place multiple orders, first for the parts that needed to be replaced, then for the proper shims. But it's definitely doable.

I got most parts from Amayama, although you can get most in the US for a somewhat higher price. If you can't find what you need here, try them, although shipping is slow as it's either from Japan or UAE.

But, definitely first check if the trans can handle that sort of power.

Ive always understand it probably would but with less aggressive driving. No flat foot shifting, hard launches etc.

I'm planning on pushing this car to 800whp or so I don't want to worry about the drivetrain much.

I did order a bunch of parts to rebuild it, all new bearings, synchros, keys, springs, shift forks and a 300m output shaft. My hope is that it will hold me Over until I can get a dog box.

 

[jdxnc]

Ive always understand it probably would but with less aggressive driving. No flat foot shifting, hard launches etc.

I'm planning on pushing this car to 800whp or so I don't want to worry about the drivetrain much.

I did order a bunch of parts to rebuild it, all new bearings, synchros, keys, springs, shift forks and a 300m output shaft. My hope is that it will hold me Over until I can get a dog box.

In my experience, it's not flat foot shifting, it's not hard launches, it's torque and heat. You make a much of torque you will strip 3rd or 4th on pulls. I've never broken a transmission on a launch in over 14 years, all have been during a 3rd or 4th gear pull, simply peeling the teeth right off.

At 800hp I wouldn't even bother with an oem rebuild, go right for the PPG gearset or go auto.

 

[CrackedDSM]

In my experience, it's not flat foot shifting, it's not hard launches, it's torque and heat. You make a much of torque you will strip 3rd or 4th on pulls. I've never broken a transmission on a launch in over 14 years, all have been during a 3rd or 4th gear pull, simply peeling the teeth right off.

At 800hp I wouldn't even bother with an oem rebuild, go right for the PPG gearset or go auto.

I like to hear this! Just launch the sh*t out of my car and never let it leave 2nd gear under power. (slightly kidding)

Stupid question(hope it triggers someone) but...is there any way to make a transcooler for our M/Ts? There's not a "pump" per say for the fluid I know...but could you use a small volume fluid pump to help with heat? IDK, just spitballing here.

 

[Anfurnyy]

In my experience, it's not flat foot shifting, it's not hard launches, it's torque and heat. You make a much of torque you will strip 3rd or 4th on pulls. I've never broken a transmission on a launch in over 14 years, all have been during a 3rd or 4th gear pull, simply peeling the teeth right off.

At 800hp I wouldn't even bother with an oem rebuild, go right for the PPG gearset or go auto.

That's good to know, actually.

This trans will basically be a backup, and maybe for awhile while I'm dialing in the tune. I'm still going to go PPG, but don't have the money for it right. Rebuilding this one costed me about $700.

 

[jdxnc]

Stupid question(hope it triggers someone) but...is there any way to make a transcooler for our M/Ts? There's not a "pump" per say for the fluid I know...but could you use a small volume fluid pump to help with heat? IDK, just spitballing here.

There was someone who did it, can't remember who currently, needed an external pump. I looked into it and in the end determined it was not really worth the effort for myself with a predominantly drag car.

 

[XC92]

Ive always understand it probably would but with less aggressive driving. No flat foot shifting, hard launches etc.

I'm planning on pushing this car to 800whp or so I don't want to worry about the drivetrain much.

I did order a bunch of parts to rebuild it, all new bearings, synchros, keys, springs, shift forks and a 300m output shaft. My hope is that it will hold me Over until I can get a dog box.

But what's the point of a lot of power if you're not going to use it? You can check with experts but I'm pretty sure that the stock trans would basically self-destruct if you use it in a 500HP+ DSM, and possibly even less. My Talon is stock, 195HP, and I don't race or push it to the limit, so I'm not worried and my rebuild has held up.

 

[Anfurnyy]

But what's the point of a lot of power if you're not going to use it? You can check with experts but I'm pretty sure that the stock trans would basically self-destruct if you use it in a 500HP+ DSM, and possibly even less. My Talon is stock, 195HP, and I don't race or push it to the limit, so I'm not worried and my rebuild has held up.

The point is to have working backup so I can still go to shows, drive around town, go on cruises while I'm fixing the built trans. Trust me when I say I use my cars. This isn't just a drag car, It's going to be driven back and forth to work and stuff multiple times a week, cruises, car shows and what not.

 

[jdxnc]

But what's the point of a lot of power if you're not going to use it? You can check with experts but I'm pretty sure that the stock trans would basically self-destruct if you use it in a 500HP+ DSM, and possibly even less. My Talon is stock, 195HP, and I don't race or push it to the limit, so I'm not worried and my rebuild has held up.

They can handle a fair amount of power when shimmed accordingly, I managed to make one last almost 3 seasons of mid 10 second passes.

 

[bastarddsm]

If you really need a cooler, the front differential gear will pump all the oil you could ever want.

Also everyone thinks these transmissions are weak. Guys like shep went 8's on them back in the day. Stock gearset, some tweaks in the synchro department. Find any other stock manual transmission that would survive a whole racing event on one transmission going that fast. Stuff that muscle car guys think are tough (m22, A833 Toploader) ect, won't usually do it. A toploader for example in a lighter weight small block car starts giving up in the 10's, and them gears are massive compared to ours.
The stories were that back in the day the honda's would bring 3 trans, one for qualifying, one for elims, and one for finals. Ours would at least last the weekend.

 

[jdxnc]

The stories were that back in the day the honda's would bring 3 trans, one for qualifying, one for elims, and one for finals. Ours would at least last the weekend.

They still do this. Guy at WCF were replacing PPG parts after qualifying Saturday, like cracked input shafts etc. in preparation for eliminations on Sunday.