Transmission issues

[c.stratton04]

My transmission recently broke and I want to know the cheapest way to get my car working. Whenever I try and put it into third, it grinds unless I double clutch it. I can't even go into fourth. 1&2 and 5&R work fine. The car is a 91 MR2. Do you guys think I should take it to a shop to get repaired, buy a new tranny online, or try and find one off a totaled MR2 in a junk yard? Also, if i should buy one offline, what is a good site? Thanks.

[MagicRat]

It sounds as if the synchro rings are gone and possibly the splines for one gear are broken.
How long do you plan on keeping the car?
If you will have it for a long time, rebuild the trans you have. Make sure the shop that rebuilds the trans also installs it. That way, if they screw up on the trans, they are also responsible for installing a good one.
It will cost more than a wrecking yard transmission, but you know what you will get.
Junkyard parts always are a bit of a mystery.
Also, with your car, almost half the cost of fixing the transmission is just the removal and replacement. If the junkyard trans is bad, you must remove and reinstall it again, at your cost.
For the same reason, don't buy something on the net. If it's also bad (sometimes it can happen), YOU are sitll responsible for the cost of removing and reinstalling a good one.

[c.stratton04]

we plan on doing the install ourselves, so it might be worth it to try and get one from a junk yard, and potentially save a lot of money... and if it is messed up, we will just have wasted some time, but no money.

Thanks for the reply though...

[BeEfCaKe]

Can you please explain to me, how exactly do you "double clutch" when you "put it into third"(from this statement, I'm assuming you are referring to up shifting).. AFAIK...double clutching is for downshifting...

[c.stratton04]

Double clutching is mostly used for downshifting to get the transmission's rpms up to make it match up smoothly to the engine, but you can also do it when upshifting. before they had synchros they had to double clutch so the gears wouldn't grind as much. when i double clutch, i put the clutch in, move the shifter into neutral, take the clutch out, give it gas, clutch in, shifter into third, clutch out, gas. just like downshifting. because it doesn't grind, i agree with magicrat that is sounds like the syncros are messed up.

[Moppie]

Toyota gear boxs have a reputation for failed scynrhos.

Foruntalty, they are quite easy gear boxs to work on, and if you have the right gear their not that hard to get out.

If you've done a lot of mechanical work before (prehaps rebuilt an engine or two) then theres no reason you can't replace them yourself.
Just make sure you have a proper shop manual with you, and you may need access to a press.


And I have to agree with what MagicRat said. If you want to keep the car for a long time then rebuilt the gearbox.
A used one will only have the same problems, but a rebuilt one will be almost as good as new one and more than worth the higher cost.

[c.stratton04]

do you guys have any guess of how much it would cost for a rebuild?

[MagicRat]

Originally Posted by c.stratton04

do you guys have any guess of how much it would cost for a rebuild?

Thats hard to say because it depends on what has gone wrong. A typical standard transmission is quite simple, and not too much can wear out. I would say $500-1000 to thoroughtly inspect it, change gaskets, seals, synchro rings and the bearing races. Depending on the transmission design, there may be lots of loose roller bearings. Frequently, these are not replaced if they are in good shape.
The problem arises if there are any other damaged parts, such as broken gear teeth, etc. These would be an additional cost to a rebuild.
I might suggest that if you can re and re the transmission, try rebuilding it on your own. Compared to an automatic trans, or an engine, the manual trans is easy to rebuild.
You should be able to get a complete kit, with all new seals, synchros, important bearings etc, and instructions.
Also, change your clutch, if you have the trans out. Even if it still looks good, change it now if you are keeping the car.