6 speed LSD Mk1 gearbox build

[kaiowas]

Much appreciated, cheers Paul. I'll PM you my address.

[stragenmitsuko]

Following/reading this thread with great interest .


Assuming I'll keep the stock mk1b differential , is the C60 the only option as a donor .

I think round here , I'm in belgium , a corolla transmission like the c64/65 or the c160 will be easier to source .

Pat

[PW@Woodsport]

Any C series can be used, and will all bolt up to a Mk1b bellhousing.

[kaiowas]

Am i right in thinking that the Celica box *must* be stripped down properly?

I'm aware of a shortcut you can take on the mk1 gearboxes to just remove the bellhousing by undoing all of the external bolts, then you can seperate the bellhousing enough to get a spanner inside to unbolt the reverse selector plate allowing the bellhousing to come off, I did this succesfully when removing the LSD from my 5spd mk3 box and even manged to put it together again afterwards (alhough it was a little like keyhole surgery!)

As I wasn't planning on rebuilding my box i was going to use the same method to build my 6speed however when i tried to open it yesterday i couldnt get any significant separation between the bellhousing and the main casing and looking at your pictures now it appears that the reverse selector is different which presumably means ill need to strip it down from the other end (ive ordered some proper bearing/gear pullers as the pullers i had arent really up to the job)

[stragenmitsuko]

Yes I understand that they all bolt right up to the mk1b bellhousing ,
but what about mounts and shift linkages .


I can imagine that some of them will be plug and play , like the c60 you recommend , while others may , - or may not- need modifications and or custom made parts .

I'de just like to clear that up prior to start searching for a gearbox .
Pat

[PW@Woodsport]

Ok one at a time...

Kaiowas, the celica box must be stripped down properly, there are no shortcuts, it is not possible to just swap the bellhousings over, besides the diff needs reshimming for preload in the new case so it needs to be stripped from the 6th gear downwards.

This is where the years of experience building these comes in, it is not a simple job and requires specialist tools, but it is the only way to do it properly.

If you need any help with the stripdown proceedure just ask.

Pat, think about where all of the mounts and stuff attach to? It all bolts to the Mk1b bellhousing, so the rest of the C series is irrelevant, as long as the new C series has the old 5 speed selector drop arm fitted it will all be plug and play, trust me.

[stragenmitsuko]

Ok Paul , got it . The bellhousing holds all the mounts , and
the 5 speed selector fits and is to be used on the six speed .


Time to go searching for a C six speeed then .

pat

[PW@Woodsport]

Well the 5 speed selector arm only fits when you rotate the selector shaft 180* during the gearbox build, but yes it works.

I have good Celica 6 speeds in stock if you can't find one.

[stragenmitsuko]

Thx Paul , if I haven't found one by the end of next month I'll probably take you up on that offer .
Needs to be shippped to Belgium though ....


OT

You're the inventor of the datsun cherry repair panels rear arch fix if I'm not mistaking .
Luckily I ordered a set a couple of years ago from a site called crashrepairpanes , car body panels or similar . All those sites seem to be gone now , and I doubt the repair panels are still available .

Anyway , do you have pictures of the repair panels , and the rear quarts ready to be welded ?
What I 'de like to know is what section of the rears do you cut away , and how do you weld in the new ones . Overlap , but to but , repair panel on the insde or on the outside .... you know what i mean .
There are several way's to do this , andmost likely you've already found waht works best .


Pat

[PW@Woodsport]

Hi Pat, i don't have many pics of that, and it's taking this gearbox thread off topic.

The Cherry arch method is just the same as any other method, used the outer 2" of panel and tuck under the original, weld and blend.

[stragenmitsuko]

Well I managed to find two C60 transmissions for a very reasonable price
at only half an hour drive away .
One with a "scratching " noise when shifting from 3th to 2nd .
One with high mileage , but supposededly in good condition .

However ,
To my surprise , finding a mk1b transmission seems to be a little harder .

Paul are there any other toyota's that use thesame ( C52 I think ) gearbox ?
MR2's have alway's been pretty rare in Belgium but there are plenty corolla's and celica's .

According to wikepedia the C52 can be found on
Toyota Starlet GT Turbo
Toyota MR2 (AW11) 1986–1989
Toyota Corolla (E90) 1987-1992 with 4A-F, 4A-FE, or 4A-GE engine
Toyota Corolla Levin (AE101) / Toyota Sprinter Trueno (AE101) - early years
Geo Prizm 1990–1992
Toyota Corolla (E120) with 1ZZ-FE engine in Brazil (South America market), Europe and JDM.
Toyota Carina II (AT170) 1988-1992 with 4A-F or 4A-FE engine
Toyota Celica (AT180) 1989–1993 with 4A-FE Engine

Wikepedia know to be not alway's accurate , I thought i'de ask first .

Pat

[PW@Woodsport]

There may be others, but you need to be careful, because you are using the Mk1 Mr2 bellhousing because the slave cylinder mount etc are all in the right place, that may not be the case with a non Mr2 C52.

If you want a Mk1 Mr2 C52 i have one in stock.

[kaiowas]

Pullers etc finally turned up this week so I could crack on again. Got the Celica box stripped down but it's not in great condition so I need to try and work out what's happened to it and whether to replace the knackered parts or get another box and hope for better luck.

When I opened it up there was a lot of swarf in the casing and the 3rd/4th selector fork/sleeve were showing a lot of obvious wear. On further inspection the needle roller bearings on 3rd and 4th have disintegrated, the rollers were all loose and the plastic housings were nothing more than molten remains. The oil feed hole on 4th was blocked with molten plastic but I don't know whether that was cause or effect. The synchro ring on 4th is also pretty beaten up. I haven't stripped down the output shaft yet but the selector fork/sleeve on 1st/2nd are showing similar wear to 3rd/4th although not as bad, the gears are spinning pretty freely (4th was really lumpy so I knew something was wrong before taking it apart) so I expect the needle roller bearings to be ok. The synchro ring on 2nd is cracked though.

At the moment the parts list is looking like:

2nd and 4th synchro rings (might replace 3rd as well given the intended use of this box)
Needle roller bearings on 3rd and 4th
3rd/ 4th selector fork and sleeve (Plus maybe 1st/2nd)

[PW@Woodsport]

By the sound of it you would be much better off with a fresh 6 speed than that one.

[kaiowas]

Slight update,

I've gotten around to stripping down the output shaft. More molten needle roller bearings were discovered. I'm beginning to suspect that this box has been run with very low/no oil at some point to have caused all of these bearings to have overheated. The extra movement in the gears caused by the bearing damage has then subsequently caused the unusual selector wear.

I've managed to clean everything up and source all of the necessary damaged parts from the 5 speed mk3 box and now have reassembled input and output shafts so I'm going to carry on, build this one up and see how it goes. Next step will be the diff preload.

Longer term I'm aiming to build a second gearbox so that I always have a spare on hand (some of our events can be pretty close together timewise so having spares ready to go at short notice is always worth it!), as a consequence I'm not too fussed if this one doesn't last, I'd rather pick up the experience with used components that haven't cost me a lot than spend a fortune on new parts and then break stuff. Depending on finances at the time the second gearbox might be a more comprehensive rebuild with some new parts.

So far I reckon I'm only into this for about £400 and that's including about £150 worth of tool purchases so it's been worth it just for the knowledge gained.

[kaiowas]

Gearbox is all built and sealed up \o/

Will be a few weeks before I get to put it in the car and see if it all works, in the meantime I've refitted all of the Celica selector bellcranks etc and it looks like they'll foul on the clutch release lever (Looking at the 2ZZ bellhousing the clutch lever has been moved further down.) Do you just use the bellcranks from the mk1 box to get around this?

[PW@Woodsport]

I use the Mk1 bellcrank, and make sure the selector rod has been flipped 180*.

I just built and installed a customers 6 speed this week, so it's all fresh in my head.

[kaiowas]

6 spd is finally in!

Couple of issues to look at tomorrow but I've been for a short drive and all gears are engaging without any crunches, bangs or anything trying to exit the casing so that's a start!

One thing I've notced is that the gear lever doesn't seem to be self-centering properly across the gate, it tends to sit somwehere between 1st/2nd and 3rd/4th, do you normally need to adjust this at all Paul?

[PW@Woodsport]

No never, in fact there is nowhere you can actually adjust that, the position of the gate is governed by the position of the gate bellcrank at the gearbox end.

Make sure your cables are clipped in correctly at both ends, make sure both bolts are in the top of the gate selector on top of the gearbox, and that the square selector peg that meshes the two selectors together is there and hasn't popped out.

After that i'm not sure what you've done, because when you use the Mk1 selector arms it should all be centred correctly.

[kaiowas]

Sorted it now. I think the main issue was the bracket on top of the gearbox was slightly bent out of alignment compared to the one that was previously on the car. I refitted the one I had been using and it was a lot better but not quite spot on. I filed out one of the holes to elongate it a touch which has allowed me to fine tune the positioning and it's shifting lovely now.