Gearbox rebuild 4 cylinder

Current unit ok, however I have a spare 4 speed gearbox that I would rather recondition prior to fitment, rather than maybe have to fit, remove, and refit again sometime in the future. Have looked at 5 speed Toyota conversion but costly at £2k. LT77 in a 4 cyl certainly isn't without issues, so does anyone know of a good rebuilder ie do you know someone who has rebuilt your 4 cylinder box to your satisfaction, (I am near stockport but would definitely be prepared to travel to the right man for the job) and can you give an idea of cost. Obviously if the job is cost prohibitive maybe the Toyota is the way to go.
As always any input welcome
 
4 speed boxes are pretty reliable, and not difficult to rebuild, the biggest problem is the price of the rear bearing, (about £175), add I reckon another £50 odd for the first motion and laygear bearings, plus a release bearing, selector striker lever and gaskets and it's expensive before any labour and unforseen hard parts that might be needed, which would tend to make me want to find a known good used box and fit that because it won't cost anywhere near that. You could strip your spare box to see what it needs, but unless you're not going to fit bearings your in for those costs whatever.
 
It's i think about 9 years now that i rebuilt mine at home with some basic tools and following the proper manual, as it was rather noisy in the first 3 gears.
I managed to find almost all the bearings new in the local SKF shop at a very reasonable price. The exception was the rear mainshaft bearing that is available now but at a price. Back then it wasn't, but even if it was, i am not sure i would justify the cost. Anyway, i left the rear maishaft one well alone, and i replaced all the others. Now, 9 years and 185,000 Kms later, i still have a silent gearbox, that shifts nicely with a good quality oil in it.
 
Thanks for the replies guys, from what H says finding a good known gearbox would be the most economical solution, however I would prefer peace of mind that comes with a recon (although with the unpalatable extra cost!) so again if anybody can recommend anyone who can do this it would be much appreciated.
 
It's i think about 9 years now that i rebuilt mine at home with some basic tools and following the proper manual, as it was rather noisy in the first 3 gears.
I managed to find almost all the bearings new in the local SKF shop at a very reasonable price. The exception was the rear mainshaft bearing that is available now but at a price. Back then it wasn't, but even if it was, i am not sure i would justify the cost. Anyway, i left the rear maishaft one well alone, and i replaced all the others. Now, 9 years and 185,000 Kms later, i still have a silent gearbox, that shifts nicely with a good quality oil in it.

Any advice going into a box rebuild Demetris?
 
Any advice going into a box rebuild Demetris?

Steven, as i have done only one P6 gearbox, you understand that i am hardly an expert. Therefore i cannot add anything new to what has already been said. Just to sum up my experience, i have replaced almost all the bearings with new (the best quality i could find) and followed religiously the factory manual, especialy regarding the tolerances. Obviously as you strip you should check everything for wear and replace as necessary, but since you are an engineer you know it better than me. If you need a new mainshaft rear bearing, brace yourself!
 
Steven, as i have done only one P6 gearbox, you understand that i am hardly an expert. Therefore i cannot add anything new to what has already been said. Just to sum up my experience, i have replaced almost all the bearings with new (the best quality i could find) and followed religiously the factory manual, especialy regarding the tolerances. Obviously as you strip you should check everything for wear and replace as necessary, but since you are an engineer you know it better than me. If you need a new mainshaft rear bearing, brace yourself!

This is my first gearbox job I must admit. So you're already one box ahead of me!
I have two spares. One from my old P6, that was quiet apart from an input shaft rattle. Another was a $40 eBay purchase from about 10 years ago. It is in unknown condition. However, the input shaft is nice and stable. I've started with the unknown box as I feel like if I make a mistake I don't mess up a good one. So far it came apart fairly easily apart from releasing the input (primary) shaft and bearing from the bell housing. I think the two crescent plates with two studs each are stuck in the bell housing. So I've left them with KB blaster overnight and will keep at them. the teeth of the unknown box look in very good condition. However, there's some sings of water damage on parts of the box.

Looking at things, I might try moving the good bearing to the good box. They really do feel almost new! It feels pretty good getting to know these boxes better. Its the one area of the car I've not investigated other than a new clutch in the past.
 
By the way @Demetris Have you removed just the box instead of the factory manual approach of engine/gearbox removal? Is it easier in your opinion?
 
Steven, it has been a good few years now so i do not remember details, but following the manual i haven't had any problems taking everything apart. Like you, i combined parts from 2 different boxes and i was lucky to have one box with almost new baulk rings and selectors. I would say that provided that i did my study, it was a pleasant and easy enough procedure, and apart from a DTI gauge it didn't require any special tools. Ah yes, drifting the bearings in and out did not made me very popular with the neighbours at the time!
Regarding removal / refitting of the box, i would say it really depends on your experience and the facilities available.
If you know what you are doing and have the car on a 2/4 post or over a pit it is definitely faster removing only the gearbox under the car.
However i have done it working on my own with the front of the car supported on stands, and it wasn't a pleasant experience, especially refitting. Just because i could not balance the box on a trolley jack at the correct angle to align it properly, i ended up lifting it with my hands and supporting it on my chest to fit. Now the box isn't really heavy, but since i was working in an awkward position it made things more difficult than they should be. Moreover you should take into account that the box wasn't really made to being taken out in this way, so you have to rotate it to bring the starter pinion hump on the top, and even then tolerances are rather marginal mainly at the left of the transmission tunnel. If i had to do it a second time, and had an engine hoist available, i would prefer to remove the box along with the engine. Yes, it takes more time, you have more things to remove / refit, but for me that i am a (very!) amateur mechanic and prefer taking my time, this method just suits me better.
 
The first job that I ever did on a P6 was removing and rebuilding the gearbox - 2000TC a very long time ago.

I didn't have a work bench so had to rebuild it on the floor in my grandfather's shed. I took the box out on its own, then strippped it, and rebuilt it using just basic tools and HBOL. From memory it was a right pig to get out, and back in again, so if you have an engine hoist, take the engine out as well.

I was quite handy with a spanner, growing up in a Motorcycle garage and having access to a very large number of old British bikes to play with, but this was the first time I have ever worked on a car. I'm just saying this, because if a seventeen year old with no training and only limited mechanical knowledge can do it with a few tools and a cheap manual, it can't be that difficult. You may however need a certain level of determination :)

Richard
 
Thanks Richard for the reply.

Finished the spare box last night! All looks good and with luck I’ll have a leak free box to match my leak free engine now.

I’ve had the engine and box out together a good few times having rebuilt the engine, pulled it for engine bay respect etc.

I am considering the box only removal as I have to move the two brake servos on the NADA model 2000TC. But this is good news.
 
I overhauled a gearbox some years back for a friend. If you follow the manual it shouldn't be too difficult and make sure the measurements are adhered to. The only mistake I did was that I didn't fill it up with oil when still on the bench. Unfortunately one of the gaskets had moved slightly when I was putting back together . The gearbox was filled when it was back inside the car and leaked. I offered to help remove it and replace the gasket but the owner was adamant that he did not want to go through the hassle of removing and refitting the engine and gearbox( It seems he had a hard time putting it back in). So he loosened slightly the bolts, applied instant gasket, and tightened and to date it hasn't leaked. I still regret to this day not having filled it, but my reasoning then was that since he needed to transport it back to his place, I avoided the risk of spilling oil while in transit. To repair while on the bench would have been really easy!! On the plus side whenever we meet and the discussion turns to his Rovers , he always says that the gear change on this box is the sweetest he has. Enough ramblings.

Regards
Richard
 
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