Mainshaft Sleeve

[JackIIA]

I've got a brand new sleeve bushing for the mainshaft. This is the brass 'pipe' that the 2nd and 3rd speed mainshaft gears sit on. The tolerances are too small though, and so I will be replacing it.

I'm told by the company that provided it, that Land Rover now replaces such sleeves with a 2 piece unit. I think I may have heard something about this, but if anything I thought it was an older version that was designed this way.

The only new style sleeve I'm aware of is one that is made of better materials, and is identifiable by a groove in the flange (the sleeve in photo on right), while the old style sleeve has no such groove.

Does anyone have such a two piece style - or can shed some light on this?

Thanks

[JackIIA]

well, because i'm a bit obsessive in getting answers to inane questions....I'll answer my own.

If you're doing a rebuild of a series IIA transmission, it appears the mainshaft sleeve went through 3 iterations (according to my research/questions/answers). The first was the ungrooved flange style, which had a track record of wearing out prematurely (whatever that truly means). The next was of better material, denoted by the same style of sleeve, except with a groove on the flange, denoting this fact. And the third, was a two piece sleeve. This last iteration was because the 2nd iteration of sleeve tended to snap in half.

case closed, i hope.

[Les Parker]

Beware on your choice of bushings !
The O.E. is made of phoshorus/bronze.
Most of the replacements I have seen are made of a high content brass.
Thus they do not absorb the qualities of the 75/90 W oil, causing early failure due to lack of heat dissipation.

[JackIIA]

Good to know Les. I think the one I have is genuine, or at least it came in an LR box!

Thanks

[robert wood]

The two piece series III bushing can be used but IMHO it is no better than the one piece type. I've been rebuilding these gearboxes commercially for years. Les is right that you should watch your supplier - there are a lot of very dodgy bushings out there made by our friends in the colonies.

My opinion is that once you have the clearances set up correctly (using the old circlip) you should clean the parts well using brake cleaner and do your final assembly using red 'locktite' between the bushing and the shaft. This prevents both ends of the bushing rotating and largely prevents the common center fracture. Downside is that you make it harder to take apart if ever you have to do it again.

The bush is normally prevented from rotating by a pin driven into the mainshaft. The fit between the pin and the bush is a point contact and even in the best maintained vehicles this frets and eventually fails. The common cause of failure is towing the vehicle with the transfer case engaged.

I am of the opinion that the debate about corrosion in copper based alloy component caused by modern oils is an urban myth. Tho older el-cheapo oils have far more sulphur in them and I've yet to see a component corroded in a gearbox or overdrive!

Ray

[JackIIA]

ray thanks. i had not thought of the locktite approach. it initially sounds counter intuitive to me to use for a bushing on the shaft. but you're completely right, since it's pinned there, why not? i might use locktite blue. don't know if medium strength is good enough, but certainly worth a try and gives me an 'out' if i do need to disassemble.

any reason not to reuse the original bushing as long as the tolerances are OK? There is some sign of wear (circular surface striations, not deep though). I don't know what the composition of the original bushing is - brass or brass alloy. It was a two piece unit. Thanks