Gears Crunching Going From 3rd To 2nd

[koolio1234]

I recently purchased a 94 Corolla Ae101 which has a silvertop 4age 20 valve engine. The engine is running great but the 5 speed gearbox in it seems to crunch when going from 3rd gear to 2nd gear. I think it might be due to a worn out synchromesh, is this correct to assume? If this is the case it means the gearbox will need to come out and get reconditioned which could get expensive.

 

1. would it be cheaper to just buy a 2nd hand gearbox and get it put in

 

2. Could I do it myself or does it require lots of expertise and mechanical knowledge.

 

3. Most importantly, what is the name of the gearbox in my AE101 seca, couldnt find the name anywhere.

 

4. Are there other corolla gearboxes that will also fit and mate up with the silvertop 20v?

 

I'm new here and new to toyotas so any help will be greatly appreciated.

 

thanks

 

:(

[altezzaclub]

Can you double de-clutch when you change down?? First thing the girl learnt when I taught her how to drive. (and the son, 10years back)

 

That matches the revs to the lower gear and the synchros don't do any work.

 

When you're practiced you won't need to use the clutch at all going 3rd to 2nd!

[Hiro Protagonist]

1) If you can come across a secondhand gearbox in decent shape for a decent price, it will most likely be cheaper than to rebuild the current box (for reasons below)

 

2) If you're not handy with a spanner and don't have a good set of tools (you'll need to drop the gearbox or both the gearbox and engine out of the car so an engine-crane or block-and-tackle is fairly necessary) then I wouldn't attempt it, if you've got mates who like beer and have the tools and know how to do it then I'd bribe them with beer to do it for you, or if you have neither of the above then take it to a mechanic

 

3) It'll be either a C52 or C56 gearbox. Very hard to tell the gearboxes apart visually, easiest way is by gear ratios.

 

4) If it's a C52 gearbox, then it's the same box that came out in locally delivered AE102s, as well as AE93 and AE82 4AGE-powered Corollas. Shouldn't be too hard to get your hands on one for a couple of hundred bucks. The C56 is only from the 20v 4AGEs (so AE101 and AE111 imports), but they still aren't super rare and don't command too much of a premium over the C52. C160 six-speeds on the other hand......

[koolio1234]

Can you double de-clutch when you change down??

 

yep, ive been using that technique since I got the car to avoid that horrible crunch, it works mostly but still ocassionally hear the crunch.

 

 

I'll be ok to stick with it for a while until I can source the C52 gearbox at a good price ($200~) or C56 (which i hear has slightly better ratios but costs a little more and harder to track down)

 

 

 

Thanks for the help guys, really appreciate it.

[altezzaclub]

Ok- so you can keep driving without a problem.

 

Try to drive the gearbox you're going to buy, you might find a lot of them have that problem if its a design fault.

 

You would need a couple of tools you might not have like circlip pliers to do it yourself, but the expertise should be on here somewhere.

 

I've had gearboxes apart but never had to put new synchros in.

[koolio1234]

Ok- so you can keep driving without a problem.

 

Try to drive the gearbox you're going to buy, you might find a lot of them have that problem if its a design fault.

 

You would need a couple of tools you might not have like circlip pliers to do it yourself, but the expertise should be on here somewhere.

 

I've had gearboxes apart but never had to put new synchros in.

 

yeah, I've realized this issue has come up a few times for these gearboxes. It seems to be the norm for gearboxes with high km on them or ones that have been thoroughly abused. I'm gonna wait and see how bad it gets. at the moment its still pretty ok, especially if I rev match or blip the throttle a little bit before I drop to second. If it does crunch though, is it actually damaging the gears or something major?

[altezzaclub]

I expect its crunching the little brass teeth on the synchro rings, not the actual big steel gears, so you won't lose a gear.

 

The gears make a different sound when they grind together, much louder and scarier!

[koolio1234]

I expect its crunching the little brass teeth on the synchro rings, not the actual big steel gears, so you won't lose a gear.

 

The gears make a different sound when they grind together, much louder and scarier!

 

Thats a relief, thanks for the help mate. I'm becoming a big fan of the rolla the more I drive it.

[TRD ke70]

I have struck this problem before many times.

If it's what i think it is, there are a couple of things you can try.

 

It comes from the synchro cone polishing the synchro hub, then the cone can't grab the hub to mesh the gears.

I've been told it's to do with the quality of the gear oil that causes this.

 

You could try changing the oil, but i have found this to only last a week or 2 before the problem returns.

 

The only other way is to strip the gearbox and sand blast the synchro hub surface, this puts a rough surface on the hub so the cone can grab it better.

And while you have it apart change the cones.

 

If you have ever heard of using valve grinding paste on the cones and the hubs, it's the same principle!!

[Tazrolla]

before looking at buying another gearbox or repairing the one you have id have a look at the clutch, i know ya saying only between 2nd and 3rd or 3rd to 2nd but might just be a simple clutch adjustment needed or another clutch plate.. thats not to say that it isnt the synchro thingy but this could be a cheaper option to check out 1st

 

I'm not refering to the clutch being worn but more to the point of that its not declutching eg; cable/hydrolics may need to be tighten up or re bleeding

[clubby2084]

Although it's a different gearbox but, my old man's Hilux snags 3rd on the down shift. Just a mild crunch.

He changed the oil in the trans and the problem went away. The manual trans in his Hilux only holds about 2 liters.

That was about 4 thousand kilometers ago. It still seems to be OK.

 

As you recently bought the car, do you know when it was last done, if ever ?.

Can't hurt.

[Satyr]

Hehe, i have the opposite problem. The crunch feels more like it's in the gear selector i.e. just under the leather boot.

 

It will generally only crunch shifting UP to 3rd at around 6krpm or 80km/h. It only happens when i shift quickly though.

 

Running a 7afe AE102R. Thinking it might be slack selector cables.

[koolio1234]

I will do a transmission oil replacement to see if the problem goes away.

 

Can anybody recommend some reasonably price oil to use for the gearbox? I'm not too sure what these gearboxes use.

[Felix]

After looking around a heap on different forums, I am about to try Castrol VMX80 with Nulon G70 treatment in the missus' AE92.. Seems to be the best option before spending stupid amounts of cash on gearbox oils like Redline.

[Satyr]

Yea, everyone i've talked to really couldn't justify the cost of the Redline. If your getting it done for you, shop around, i found HUGE variation in price for getting this done. $60 - $350. Guess which one i chose :)