1991 PZJ77, R151F transmission starting to give a little bit of bother changing 3rd to 2nd (1 Viewer)

[MrThing]

Title is the basics of it. I’m looking for advice on diagnosing the problem, and getting it fixed.

Currently maybe every 10th change down I’ll need to give it a bit of a bump to shift from the middle of the box to the 1st/2nd side of the box. Not a huge issue at the moment, but I am conscious it could get worse.

 

[AirheadNut]

How many km's on it? If I'm understanding you correctly there is an issue with getting the shifter to move sideways from the 3-4 position to the 1-2 position? That might be wear in the shift fork shafts or the shift lever.

 

[MrThing]

How many km's on it? If I'm understanding you correctly there is an issue with getting the shifter to move sideways from the 3-4 position to the 1-2 position? That might be wear in the shift fork shafts or the shift lever.

You’ve understood the issue correctly.

She’s reasonably high mileage at around 380,000kms.

Do you have any advice for diagnosing between your two theories?

 

[AirheadNut]

Unfortunately there isn't a good way to check for wear in the shift fork shafts or shift lever without disassembling the transmission. Here are the parts in question; the shifter goes in a socket in the top of the shift lever, which engages with the slots in the shift fork shafts. Wear in either of those components could make it difficult to move the shifter side to side. The detents for the shift fork shafts could also be worn, making the slots in the ends of the shift fork shafts offset from each other a bit.

 

[MrThing]

Unfortunately there isn't a good way to check for wear in the shift fork shafts or shift lever without disassembling the transmission. Here are the parts in question; the shifter goes in a socket in the top of the shift lever, which engages with the slots in the shift fork shafts. Wear in either of those components could make it difficult to move the shifter side to side. The detents for the shift fork shafts could also be worn, making the slots in the ends of the shift fork shafts offset from each other a bit.

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Cool. Thanks for the input. I might start having a look around for a spare box & have a talk with some transmission shops.

 

[AirheadNut]

Could be something else in the shifter assembly as well, wouldn't hurt to pull the shifter and check the shifter bushing and make sure everything looks clean and nice down there.