Hi, I have a friend that is having issues with his newly assembled motor, the gear box is really tight in first gear, all the other gears are fine.

When you select first it won't turn the motor over going forward, but will turn over when you push backwards

He took it for a test drive and it would only drive in first with full engine power, as soon as you backed of it would lock up

Gear box is a rod change, which has been recently rebuilt

We can't think of anything that could cause this issue so he is looking at engine out to do further investigation

Any suggestions would be appreciated

Mal

moved this out of 'wanted'...

could this be caused by a mismatched laygear & gearset?

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did I tell you that I won a trophy?

whoops sorry not sure what happened their,

doubt it is lay gear issue, it moves fine in reverse and I am sure he didn't replace any gear sets, but will cheeck

what about a missing laygear thrust washer - laygear moves to one end under power and there is a washer there, but when you back off the laygear moves to the other end and grinds itself into the casing

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did I tell you that I won a trophy?

Mal, I had an 1100cc engine that I rebuilt that did a similar thing once. Was in the ute actually.

I had been driving it around for months fine. Then one day out of the blue started playing up

It would drive normal under acceleration until you backed off and the revs came down below (i cant remember what now as it was so long ago) and the gbox locked up and it skidded to a stop. It did this only 3 times and then was OK again.. wierd or what?!!... I continued on my way home only to get a further 30kms and my low oil pressure light came on so I pulled off the freeway, got out and found a trail of oil left behind.

Got a tow home and inspected. The diff pin had come loose and gouged a slot in the rear diff casing. Pulled it out and found the roll pin that holds the diff pin had been damaged. I think I have photos somewhere actually

I never rebuilt that gbox again, I sold it to a fella who rebuilt the diff and put it back on the engine and never drove it.. you dont by chance have that engine say???

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- '74 Clubman Ute project

Photos of what happened to my gbox. It honestly looks like somehow the diff pin rotated and squashed the roll pin and then was able to roam free out the cage...

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- '74 Clubman Ute project

But that was your diff pin issue causing it to lock up in all gears or just first?

I'm not exactly sure anymore

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- '74 Clubman Ute project

reading the first post again, I'm sure I'm right about a missing laygear washer....

it's something that's been left out and something in the 'box is moving into the 'normal' position as long as the engine is pulling the car, when the car is pushing the engine, the 'box is moving to where the missing part is and is locking. It could be selecting 2 gears even....

very curious to find out what it actually is

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did I tell you that I won a trophy?

Well , the issue has been resolved, main shaft bearing outer race circlip was not fitted, whole main shaft was moving and would have been jamming against 1st motion bearing, also possible binding helical gears.
Doesn't appear to be to much damage , and will be back on the road before you know it

M