1G Finally took transmission apart, advice needed on which parts need replacement. (More photos!)

[twicks69]

Detail 1st and 2nd engagement teeth. You can run the 5th intermediate gear as is, or debur it and run it.

Replace 1/2 hub and slider assembly, 1/2 fork, intermediate shaft bearings, 1/2 synchros, seals, shaft nuts, roll pins, snaprings.

Check 3/4 fork wear patterns and 3/4 gearset once disassembled.

Open up center diff, check upper/lower oiling washers and spider gear bores and oiling washers.

 

[XC92]

So, gears look ok and just need some detailing? Which is what, symmetric manual filing on each tip, or maybe a rotary tool with diamond tip used carefully?

How does the 3/4 fork look to you? I posted photos above.

I haven't taken the input shaft apart. I absolutely should even if it looks good? The sleeve looks way better than the 1/2 one, with the tips still nice and pointy.

Will take center diff apart. So I should check all 4 washers? What should I look for?

What about the front diff, it should be ok so leave as is?

Also, when I put the stacks back together with the new parts and it's time to do the solder method thing, can I leave the snap/lock rings off or just reuse the old ones (temporarily, just for the solder method) so I don't have to put in an extra order for the rings between the first order for the main parts and the last order for the shims? I was going to order any needed shims from you so I assume you also have all size lock rings.

Btw in case it matters, the car is 29 years old but the trans is "only" 27 years old since the dealer put in a '94 trans in 1994 (thus the 2nd double synchro), plus the car sat for 6 years because of various issues so it has only 21 years of driving, and only has around 53k on it. I'm guessing that the main reason the 1/2 parts are trashed was a sloppy clutch pedal that led to incomplete clutch disengagement, not years and miles of normal wear and tear.

 

[twicks69]

The gearset is a 92.6-94.

I cannot tell from your picture if there is wear on the middle tab 3rd gear side of the 3/4 fork. Check for wear. If you want to see what a worn shift fork looks like, look at your 1/2 fork. That is worn out.

Debur and clean up the engagement teeth with a 2" or 3" roloc 3m abrasive scotchbrite medium grit wheel (maroon) and a die grinder. Or some 120 grit 1/4" diameter x 1/2" long sanding drums on a dremel with a flex head. Both work fine doing this. Just takes a couple minutes.

Take apart the input shaft, it literally takes 1 minute to remove the 5th needle bearing sleeve, remove snapring, and press off the entire gear stack. You are in there, look at it.

With the center diff, it will be obvious wear patterns if you look at it. The spider washers can groove and fail, replace them if they have wear. The cross shaft likes to gall on the posts which causes damage to the spider gear bores. Check them and the spider thrust faces that are in contact with the thrust washers. The lower pinion oiling washer can sometimes break the retainer tang or get grooving, check it. The number on the underside associates to the thickness of it. The upper pinion oiling washer is notorious for failing and destroying the center diff cover and upper pinion gear. Check for wear, grooving, galling, etc. And measure its thickness.

The front diff rarely kills the spider washers or pinion oiling washers. It has a higher likelihood that it needs the roller bearings replaced. Clean them and spin them.

As for solder stuff.... you can reuse your shaft snaprings if you didn't beat them up. I typically use 1.5mm sizing for all three snaprings. Install your new tapered roller bearings and use solder to check bearing preload zero value then you can calculate what you want for preload/ endplay and select the proper shim if available.

 

[XC92]

I put the front diff back in the case piece after cleaning it and it spun without effort or noise and it stayed spinning for some time, so I assume the bearing is good.

I assume that if I take apart the center diff I have to replace both bearings?

Same for input of course, but you already said this above, as precautionary. But a cursory check of their races indicates that the bearings are in better shape than the intermediate ones. There's some roughness in the latter that the former don't have.

And when I do the solder thing, do the snap rings have to be installed AND the right thickness for it to be accurate? I'm guessing yes.

And here are better images of the 3-4 fork:

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Looks pretty worn to me. Is there a thickness range each fork should fall into, for both the axial and radial widths, at the three tab points?

Finally, what do you think of my idea of my putting together a how-to guide on rebuilding a trans? I realize that there are several out there but they don't answer the sorts of questions you tend to get and keep having to answer...like mine. This would save you the trouble of doing this ad nauseum and put it all in one place. I'd try to incorporate your responses on things like preload, solder method, tools, how to remove/install various parts, etc. It would be my way of giving back to the site and thanking you and others.

 

[twicks69]

With the center diff. All you have to do is remove the 8x 14mm head bolts; just use an impact and remove them, remove the cover, disassemble the diff. It is extremely straight forward, you do not need to remove the bearings to open the diff and service it.

With the front diff, sounds like it is good enough as it is.

If the input shaft tapered roller bearings are in good shape visually, you will simply need to confirm by doing a solder method test and measuring the zero value to make sure you can select a shim from the ones available to put it into spec. For your power levels, around 0.003-0.007" preload is fine. Use 0.062" solder for the input shaft, and intermediate shaft (front diff also uses this size solder for testing). The center diff and output pinion shaft will use 3/32" solder for checking. You can reuse your input shaft and intermediate shaft snap rings if they are in good shape, or simply compress them in a vise gently to re-shape them for reusing. If they don't snap back into their retainer groove well, then replace them. As for needing them installed or whatever, that doesn't affect solder testing. The snap rings are there to retain the shaft bearings and take up the slack. Typically a 1.5mm snap ring is used for the input/ intermediate shafts and viscous coupler. Rarely am I needing one thinner or thicker.

You had a question regarding replacement of the intermediate shaft outer tapered roller bearing and getting it off; all you need is an OTC 1123 splitter and a press and gently press from below the roller bearings. If you break the inner race lip, then you will have to clip off the cage and remove the roller bearings, then either try from the inner race lip, or you will have to gently cut a groove in the bearing race without going through it, then use a bearing splitter and press again. You can always use A LITTLE heat, not glow in the dark, A LITTLE heat only. I use a 1000W mini-ductor or a propane torch depending on the situation and sensitivity of the component. Warm it up, then spray some lube on it and press off slowly and gently. Same situation goes with the input shaft inner tapered roller bearing. On some gearsets (i.e. Evo 1-3, GVR4) it can be a little more difficult to grab the bearing with your splitter, and you need to use an air hammer with a point tool and GENTLY hit the race edge to create some separation, then put your splitter on it.

Your 3/4 fork wear looks normal, to mild wear. Look at your 1/2 fork, the grooving wear that is on the middle webbing on 2nd gear side is excessive and is a visual indicator that the fork is worn out. Does your 3/4 fork have this same type of wear? Put the fork on the slider and see what kind of free play / wobble play it has in an up/down motion vs the slider to get a better feel.

As for you putting together a tutorial with a copy and paste of all my answers, that is your call. Each person's trans can be a little different in information and a lot of it is visual identification, measuring where needed, and a lot of feel. It is flattering that you want to do the tutorial, but as for me adding more to it, well, I run a business doing this stuff and have already contributed over 15 years to this site on driveline related discussions and peoples rebuilds. A lot has already been answered.

 

[XC92]

So when taking apart the center diff, the outer bearing, being pressed onto the outer flange of the outer cover, stays put and doesn't need to be pressed out? It's not pressed onto the right side gear shaft in any way, just slips off?

And the spider washers are the 2 8's below, and are the same thing as oiling washers? What are the thrust washers, 5 & 11? And the pinions are also called spider gears? I'm just going with the terms you used above (stuff I would cover in my guide to reduce confusion).

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I was able to remove both intermediate shaft bearings in the end, w/o a problem.

The inner one by pressing up on the gears as per the FSM (to the point where it was probably not damaged but I'm going to replace it and its outer race per your and others' advice and because both its rollers and outer race show evident if still relatively minor wear, a sort of micro-pitting). I used a 10-ton push-puller and it worked just fine, although I did "cheat" by using an impact wrench and several adapter pieces.

And the outer one by having the splitter press against the rollers, which it turns out was how the FSM said how to do it. I was just concerned that they and the outer cage wouldn't be able to handle the pressure and might "explode". Didn't happen, although it probably ruined the bearing (which I'm also replacing so it doesn't really matter, although I might repurpose both to make lazy susans or some such things).

I assume it''ll be much the same with the input shaft, so I'm good there, although I'm pushing the limits of the push-puller's forcing bolt there and might have to use a press or a bigger push-puller or at least bigger side bolts.

As for the 3/4 fork, there's definitely some play when I slip it onto the 3/4 slider. Using a digital caliper (iGaging absolute) there was around 0.6mm play on the middle tab/web of both the 1/2 & 3/4 forks, although it "feels" like there's a bit more play on the 1/2. Is there more room for play on the 3/4? I'm thinking it might be safer to just replace both.

And as for the how-to, I'd obviously attribute you and anyone else and not make it seem like I came up with various steps, tips, recs, methods, etc., on my own. It just seems like a way to avoid having to answer the same core questions repeatedly and be able to focus on specifics issues and situations (and a way for newbies to not have to wade through countless old threads to find what they're looking for).

Basically it would be a combination FAQ/How-To. Folks could direct newbies like me to it and state that if there are still questions that it didn't address or any confusion, come back with it and they'll try their best to help. If I did do this it would be a while as I want to finish this job and get the car running again, and have several other unrelated things I need to do on it before that's possible. I'm thinking later this summer.

 

[twicks69]

For the center diff, it will be self explanatory once you remove the bolts and remove the cover.

I call the two little guys on the cross shaft the spider gears. I call the upper gear in the cover as the outer or upper pinion gear. I call the lower gear in the housing as the inner or lower pinion gear. Whatever, it's just a term, you will visually understand it better by looking at it directly.

The washers for the spider gears are unique to only the spider gears. The upper oiling shim is unique to the upper / outer pinion gear only. The lower oiling shim is unique to the lower / inner pinion gear only.

 

[XC92]

I see my confusion. By upper/outer you mean on the end case side, and by lower/inner you mean bell housing side, i.e. as if the trans was on the floor with the bell housing facing down. I was thinking in terms of when the trans is actually mounted in the car, where upper/outer is passenger side and lower/inner is driver side. Never mind, newbie confusion.

Took everything apart. Center diff internals look fine, no galling, grooving, breaking, anything odd-looking, etc. Only thing I saw that seemed concerning on the input shaft was some surface rust on the inner & outer hub surfaces, quite a bit more on the 4th-facing than 3rd-facing one. Seemed kind of weird for any rust to be there given that it's swimming in lube unless it was installed that way. I assume that it's relatively harmless as there doesn't appear to be any pitting and I should just scotchbrite it off and clean before reinstalling.

I'll post photos and measurements later. Everything's all cleaned up but I need a rest. I did this outside in 93 degree weather under the sun. So much for my shade tree!

Ok, next and hopefully last set of photos.

First the center diff:

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Next, the input shaft:

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3rd gear:

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4th gear:

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3-4 hub:

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3-4 slider:

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3rd synchro:

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4th synchro:

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So, what do you think? To me it looks like everything's still usable, so long as I carefully remove the mystery rust on the hub and maybe clean up the synchros a tad. The washers on the center diff look fine to me. I'll replace if they're iffy. Let me know.

Oh, when I put everything back together except the bolts, with the left side facing down, there's some play when I pull up on the right side gear, the one that the VC goes over. I measured it with a digital caliper and it was a tad over 0.5mm, around 0.55-0.58mm. Is that bad?

Also, when I try to turn the right side gear, there's this grinding sound and feel that doesn't seem right. When I pull up to take up the play, it sounds and feels a lot smoother.

Does this self-adjust once installed in the trans, what with the output shaft, detent ball, VC and snap ring installed, and everything lubed? Or is the spacing off? I read the FSM but the instructions for getting the spacing right are vague.

I'm basically set to place a large order for trans and other parts, once I hear back about these parts. I'm actually pleasantly surprised that the trans and most of its parts looks like they're in pretty decent shape for 27 years (it's a '94 trans).

 

[1990TSIAWDTALON]

I think you are doing a bang up job on the documentation as you go and asking the questions and getting the answers from some folks who's input I value!

 

[XC92]

I think you are doing a bang up job on the documentation as you go and asking the questions and getting the answers from some folks who's input I value!

Thanks. Just trying to be thorough and give as much info as I can so Tim and maybe others can give an informed opinion. I used to do QA and documentation so it's second nature.

 

[1990TSIAWDTALON]

Well I am glad you are good at it. We all "try" but not all of us are as good as others. I take pictures (usually so I can reference them myself) and share anything I can, so THANKS!

 

[XC92]

Yes! I often take photos so I can put things back together properly. My visual memory isn't that great for details, and these cars have many details.

 

[Mech Addict]

I'm really enjoying the photos, especially since I farmed my tranny rebuild to a pro, so was not able to see it all. Looks like you've gotten to about the half-way point; dissassembled and inspected, and nothing broken in the process. If you can get all the parts you need, it should be on to the assembling. Kudos!

 

[twicks69]

Replace 3rd gear synchro, it is showing enough wear on the teeth i'd replace that , along with the 3/4 shift fork. Gears look good, hub and slider looks good. Note the orientation of the hub when you press it back on the shaft that the identification marking faces 3rd gear. On the 1/2 hub, the identification mark faces 2nd gear.

As for the center differential, the cover slop is a bit loose, typically I set up around 0.004-0.010". That being said, pretty much all the OEM spacers are discontinued, the only one remaining from Mitsu is MD720678 which is 0.0366"-0.393" thick. In your case, your upper washer is in great shape. so measure its thickness to see what you are working with. it is also about $30 for that one shim. The spider gear washers are about $13.00 each. The lower pinion oiling shim is in good shape, along with the cross shaft, gearset, housing and cover. Check your upper washer thickness to see if is worth replacment, otherwise lube it up and slap it back together, and torque fasteners to spec with loctite blue 243.

 

[XC92]

3rd & 4th synchros are identical on a '94 AWD, right? But only replace 3rd, not 4th? What about the springs (also same for both) & keys? They look fine.

Any idea what could cause that rust on the hub, is it a potential problem or sign of something bad, and is it ok to carefully remove it with scotchbrite or perhaps even fine sandpaper?

$30 for an upper spacer (one deal has it for ~#24)? Damn. I guess the metal has to be extra hard to take the thrust. Any reason to consider that Torrington mod for my stock Talon?

Is this what race spacers cost, since I'm probably going to need to order some?

Btw I found some good prices and decent shipping at a dealer called Mitsubishi Parts Now out of Tallahassee, FL. Ever heard of it and are they reputable? Their parts are cheaper than any other online dealer I've found, so I'm wondering if it's too good to be true. I shot them an email over the weekend to confirm availability and they never responded.

I'm really enjoying the photos, especially since I farmed my tranny rebuild to a pro, so was not able to see it all. Looks like you've gotten to about the half-way point; dissassembled and inspected, and nothing broken in the process. If you can get all the parts you need, it should be on to the assembling. Kudos!

Before I put everything back together I'm going to try to lay everything out and take a photo. It's not like an engine but there's a lot of parts there!

 

[luv2rallye]

I'm really enjoying the photos, especially since I farmed my tranny rebuild to a pro, so was not able to see it all. Looks like you've gotten to about the half-way point; dissassembled and inspected, and nothing broken in the process. If you can get all the parts you need, it should be on to the assembling. Kudos!

This is for Mech Addict and others who wish to see the gear stacks before they're disassembled and which gear is what (this is my 2g FWD but AWD is similiar): https://www.dsmtuners.com/attachments/intermediate-shaft-input-shaft-both-in-neutral-jpg.99045/ [Note: The synchronizer sleeve is aka a slider because it slides back and forth on the hub. The hub is splined to the shaft so when in gear, the slider then connects the gear (via the gear's engagement teeth, which are part of the gear) to the shaft (via the hub).]
More pics: https://www.dsmtuners.com/threads/t...ping-out-of-first-gear.531332/#post-153780725

 

[XC92]

Amazing that all that power gets transferred with minimal loss given how many "handovers" there are:

Pistons to crankshaft
Crankshaft to flywheel
Flywheel to clutch disc
Clutch disc to input shaft
Input shaft gears to intermediate shaft gears
Input/intermediate shaft gears to hub sleeve
Hub sleeve to hub
Hub to shaft
Intermediate shaft 3rd gear to center diff
Center diff to front output shaft
Front output shaft to front diff
Front diff to CV axles
CV axles to wheel hubs
Wheel hubs to wheels
Wheels to tires
Center diff to output shaft
Output shaft to t-case input shaft
T-case input shaft to output shaft
Output shaft to prop shaft
Prop shaft to rear diff
Rear diff to CV axles
CV axles to wheel hubs
Wheel hubs to wheels
Wheels to tires

I think I'm skipping a step in the t-case. That's a lot of power transfer points. And it works!

 

[twicks69]

Your 3rd synchro looks to have more wear than the 4th and I'd replace it based on condition of the key ways and the curling of the engagement teeth.

The rust on the hub is nothing. It doesn't hurt anything. Likely a moisture issue from old fluid.

As for places that have the parts.....well, go look for them, find the part numbers, find availability, provide technical support from 20 years of direct experience, order the correct parts, pay taxes, pay transaction fees, ship parts. Thats what I have to do, and what I am providing. If you find a place that says it is dramatically lower than someone else, either they haven't updated their website in a long time, or they probably aren't in business. My prices are my prices, im essentially a middle man, if you want to go dealer direct then do it. I have to make a living too, no one else pays my bills and this is my full time job.

 

[XC92]

Their prices aren't dramatically lower, just a bit lower across the board, like say $30 for a synchro where others sell it for around $32 or $33. I've noticed that most online Mitsu dealers are within a few cents to under a dollar from each other on most items. This place undercuts them all by 3-5%. Just seems kind of odd as you'd think they'd siphon away the others' business over time but clearly the others are still in business.

 

[Mech Addict]

Yes, I often think about how many gears and bearings come between the crank and the tires, and how each one has some finite amount of backlash or clearance to work, and how those all add up (thinking u-joints also).
Let’s not forget all the parasitic losses off the front of the crank, for balancers, oil pump, cams, water pump, power steering, a/c, and alternator.
plenty of folks on here remove as many of these as possible to put that power to the ground.
strange that it is actually the ground pushing on the tires that is responsible for motion
Ok, back to this post: any luck on the parts source? You might just order from Tim for all the great guidance he has provided. Lowest price isn’t the only consideration, imo.

 

[twicks69]

Dealers business make so little internet parts sales for a large amount of them. Sometimes the numbers differ strictly on the taxes. I have to pay my cost plus 8.6% in fees/taxes and have enough in there to be viable, and then another 3.4% in paypal fees on top of shipping costs.

 

[XC92]

Obviously dealers operate on very different economies of scale than you do since they service way more cars and perform a much broader range of services, so it makes sense that they can charge less, since they operate on volume business.

To be honest it's not something I've thought much about as most things I buy these days are from some faceless corporation where you interact with a web site or cashier and not a person I've actually had conversations with, so I guess I take cutrate prices for granted.

I guess I shouldn't. Sorry for asking an inappropriate question. My bad.

 

[Mech Addict]

I’d buy everything at the local parts store if I could, but my experience with this car is that the trip is a waste of time. They can’t seem to find anything I need. I’m a very poor example of how to restore a car on a budget. I have ordered parts from lots of sources, but tend to go back to the ones who get me the parts I need most consistently, not the lowest price. I’m lucky, I realize, to have this luxury, but time is precious too, and I prefer wrenching or driving over web searches and piecing an order from many vendors.

 

[XC92]

I don't want this to come off as aggressive, what I will say is if you went to a shop in person and they gave you that much info for free you would be a customer for life. But he gives you all that on a forum and you won't even sack up and buy the GD parts from him...this guy has been here since the dawn of time and I have never seen ANY vendor contribute as much to this community as tim. I am Fing sick of people not supporting vendors and then wondering why the platform is dead...

Look man, I will price match anything you buy from tim. You find parts cheaper I will put up the difference if you go through him. If that's what it takes for you to do the right thing I will pay the difference.

Whoa! Uncalled for. I had no idea he sold parts as a regular business, beyond shims and snap rings. Obviously I knew he "sold" them when he serviced trans, but I didn't know he also did this as a standalone thing. His site doesn't seem to have any obvious "parts" section, just services.

And I figured this is a site for DSM enthusiasts and experts with members helping others when they're in a position to do so, without expecting anything in return other than for the favor to be returned someday when and where the other person is in a position to do so, and that he was basically one of the enthusiasts/experts.

And yes, you absolutely did come off as aggressive and I believe intended to. If this is going to turn this thread into something other than what it was intended to be, however worthwhile this other discussion might be, I'll shut it down or ask the mods to do so.

 

[Mech Addict]

Well that was simply out of line. We’re all supposed to be adults here. I think that attitude is a small minority, if it represents anyone beyond himself. But we all make mistakes, and it’s easy to write something that didn’t come out quite right, too. Don’t let one post make you question your validity. Plenty of others on here enjoy your contributions.