Should I replace my manual transmission?

[nalbertasr5]

Hi everyone

I have a 2000 5 speed 4WD with just under 300,000 km on it. I think the transmission may be starting to go. I can feel a vibration on the floor of the vehicle when it is parked or moving and the transmission makes a whining sound when in gear. The gear shifter is also vibrating more. Other than these symptoms it works just fine. Smooth shifts and no slipping. I had a mechanic look at it and he didn't see any bad mounts or anything like that. He thought it is most likely a problem internally like the bearings. I didn't see a lot of info on this on the forums when I searched them so I though I'd ask!

What do you guys think? Should I replace it now or wait? I was also wondering what the best option would be for a replacement. Junkyard donor? Remanufactured? Rebuild?

Any help would be really appreciated! Thanks!

 

[masphx]

Has the fluid been changed? Redline works well.

 

[jkeith.w]

that sounds like mounts to me..?

 

[nalbertasr5]

The fluid has been recently changed. Maybe I should try the brand you recommended?

The mechanic who looked at it didn't notice anything with the mounts but maybe I'll just take it to the stealership to identify the problem since they would be more familiar with the vehicle.

 

[mtbtim]

I agree with what the mechanic said about your transmission. Most likely bearing and gears are worn. Maybe your most affordable route will be to buy a rebuilt one or find a low-mileage used one.

 

[nissanh]

Don't replace your transmission. These manual transmissions are good for life. Fix the simple things.
The lever vibrates due to worn out bushing at the mount. You can get that fixed if you take it to a good machine shop.

Make sure you do few oil drain and fill cycles.
My car has 5 speed and it is 420,000 Km's and runs awesome. You can add a higher grade gear oil to see whether it do anything good. I had SAE 95 and 120 or so. No issues.

You need an OEM transmission mount. Manual transmission mounts wear out much faster than Automatic trans.

Use Valvoline gear oil.

 

[HiLife]

I would just swap it out if you can find another one ready to go.
Other than that I would rebuild the trans that's in there now.

 

[jkeith.w]

I agree with what the mechanic said about your transmission. Most likely bearing and gears are worn.

Have you drained and checked the fluid for material/slurry? Any indication besides a noise and a vibration (also at idle, which shouldn't be transmission, imo) that there is an issue with the gearbox? Does it shift fine? (synchros wear out before gears & bearings, typically)

 

[nobb]

It's very rare for the manual tranny to go bad if properly looked after. If it's making noise AND vibrating, it's probably bad internally and I doubt a fluid change would do much other than maybe allowing you to examine if there's metal filings in the drain. If it was only a bad mount, it wouldn't explain the whining sound. That's a symptom of a bad bearing.

 

[3rzrunner]

If you decide to swap it, look for a low km OEM one. I've got a marlin crawler in mine and i would strongly suggest against them... After finally, actually receiving my transmission from them (which was a big hassle), it arrived with a cross threaded fill plug, which i just brushed off as a one-off.... the worst part is the transmission it self isn't really that great, to catch 4th from 5th on a hill you have to pause in neutral for a split second, you cant go straight from 5th to 4th without the pos grinding :rant: ..idk what they did to 'rebuild' it...

oh and for the record i'm using AMSOIL manual transmission fluid.

their customer support is next to zilch, never answer emails, or the phone, and if you write your problem with their equipment on their forum, they delete it so their rep isn't hurt.

 

[jkeith.w]

It's very rare for the manual tranny to go bad if properly looked after..... If it was only a bad mount, it wouldn't explain the whining sound. That's a symptom of a bad bearing.

I'm pretty sure I have a bad bearing in my transfer case (output shaft) at 275K miles; the OP has 4WD; seems premature to indict the transmission and expect the rest of the drivetrain/mounts, etc. to not be complicit..?

I'd get a second opinion, OP, if it were me.

(on the other hand, if you swap trannys, and need to get rid of that 5-speed, let me know)

 

[mtbtim]

Don't replace your transmission. These manual transmissions are good for life. Fix the simple things.
The lever vibrates due to worn out bushing at the mount. You can get that fixed if you take it to a good machine shop.

Make sure you do few oil drain and fill cycles.
My car has 5 speed and it is 420,000 Km's and runs awesome. You can add a higher grade gear oil to see whether it do anything good. I had SAE 95 and 120 or so. No issues.

You need an OEM transmission mount. Manual transmission mounts wear out much faster than Automatic trans.

Use Valvoline gear oil.

Nothing last forever. Maybe your's has lasted so long because it's been better taken care of. Who know's what the OP's truck's history is. If there was a previous owner, maybe they abused the shit out of it and never changed the gear oil. A whining sound is indicative of a problem and something is wearing out. You could try a different gear oil, but I think it's wishful thinking it's going to do any good.

 

[mtbtim]

I'm pretty sure I have a bad bearing in my transfer case (output shaft) at 275K miles; the OP has 4WD; seems premature to indict the transmission and expect the rest of the drivetrain/mounts, etc. to not be complicit..?

I'd get a second opinion, OP, if it were me.

(on the other hand, if you swap trannys, and need to get rid of that 5-speed, let me know)

Good point. It could be the transfer case.

 

[pluton]

Good point. It could be the transfer case.

It also could be the bearings in the rear diff. A real professional should be able to tell you exactly what is wrong after looking at it for about 10 minutes.
The 5-speeds are basically continuously rebuildable, so you can pay for that, or pay for a mystery used one or "rebuilt".

 

[sport2004]

Interesting discussion...

 

[nalbertasr5]

It also could be the bearings in the rear diff. A real professional should be able to tell you exactly what is wrong after looking at it for about 10 minutes.
The 5-speeds are basically continuously rebuildable, so you can pay for that, or pay for a mystery used one or "rebuilt".

Well from what people are saying now I'm thinking my best bet would be to have a professional transmission shop take a look at it. I'd be afraid of what problems a used one may have. Unfortunately there isn't a shop like that where I live so I will have to take it elsewhere when I have holidays off to visit family.

 

[mtbtim]

It also could be the bearings in the rear diff. A real professional should be able to tell you exactly what is wrong after looking at it for about 10 minutes.
The 5-speeds are basically continuously rebuildable, so you can pay for that, or pay for a mystery used one or "rebuilt".

I'd love to see a rebuild of a manual transmission and an automatic too. I wonder if a write-up or video exists.

The only manual transmission I've seen taken apart was recently for my girlfriend's BMW Z3. A friend of mine who's a long time mechanic helped me out and we pulled the trans at his house in Nevada City because he has a lift in his garage. Getting the transmission apart was a little bit of a mystery but we finally figured it out via a write-up online. I had to go back home to work and my friend did the partial tranny rebuild on his own. The transmission wouldn't stay in reverse, kept popping out. So he replaced the shift fork a bearing or two and slapped it back together. I came back and helped him reinstall it. It was not easy because there's very limited space to get your arms up to the top bolts and a couple of those top bolts also held the starter. There was definitely some swearing going on but I finally got all the bolts in and tight.

One of the points I wanted to make with the BMW story is the transmission's early demise must have had to do with the fact there was very little gear oil in there. I'm kicking myself for not checking over the car for my girlfriend when she bought it from a friend but she said her friend regularly took it to a mechanic and it was well-maintained. When the reverse gear started having issues, I checked the trans fluid level and I couldn't feel gear oil when I stuck my finger into the fill plug hole. When I drained it, only about a cup of gear oil came out. The trans hold around 1 quart.

So, the manual trans on our 3rd Gens, due to reports from members with tons of miles on their rigs, can obviously last a long time when they are well taken care of. Just goes to show how important regular maintenance is for any vehicle. Sorry it took me so long to make my point.

 

[nalbertasr5]

OP Here with an update!

I finally have had the time to have my transmission looked at by a professional shop. The transmission has a worn-out bearing that is making the high-pitched noise it makes when in gear. They have also found the source of the vibration problem: it's the rear diff.

Now for the not-so-fun part: They are now taking apart the transmission and the diff to see what exactly is wrong. Not looking forward to the $$$$ for this (possibly $2000 and up!!!! depending on the issues) but at least they can rebuild the transmission if need be. I feel better going this route rather than using some other used transmission and taking a gamble. I'd like to keep my 4runner for as long as I can.

I won't have my 4runner for a while. It will take them about 4 more days to take it all apart Fingers crossed it's not too bad! I drained the tranny fluid a week ago to see how it looked, and there were no metal shavings and it was relatively clean, so hopefully thats a positive sign of sorts.

Has anyone here had their manual tranny rebuilt before?

 

[pluton]

I had the input shaft replaced on a W56 Aisin trans on a 91 Toyota truck once, but never a big, 'total rebuild'. I think you'd have to mistreat a manual trans for a long time to pile up enough problems for a major rebuild.
In your first post, you stated that the vibration was when parked and moving. There is no way that the rear diff can affect anything if the vehicle isn't moving, right?
Anyway, I hope they sort it out properly for you.