Cptsideways
Well-Known Member
Those of you with manual gearboxes in your 80 series may be wondering whats in there & perhaps why they appear so lumpy & reluctant to change gear.
Well as it happens they are the same gearbox as found in Supra Turbo's known as the R154, the R151 is different in ratios, input output shaft & end casings otherwise its the same. Allegedly the LC box has tougher thrust washers too. As I seem to munch a few of these R154 gearboxes on a regular basis (nothing at all to do with 520bhp & 450ftlb of torque of course) I've got to the stage where need to be handy at fixing them. So here's the latest one thats in the garage today.
Now there is a company in the states called Marlin Crawler who make a few upgrade parts for these & its well worthwhile fitting them for the minimal cost & its makes the boxes pretty much bombproof.
Things that break:
Centre Bearing Support Plate: this is made of cheese from the factory in R154's, they are pressed steel & flex under hard use, once stretched the bearing on input shaft wobbles about, if it gets really bad you can't select gears. Wose case it munches everything. Marlin Crawler make an upgraded part thats machined & its a lot lot tougher.
1st/2nd Gear Thrust Washer: These break up due to shear/shock on high performance stuff anyway, usually caused by rapid shifting under load. Allegedly the LC one is not made of cheese, its a different part number to the Supra one but is otherwise identical.
Things that are obviously a bit iffy: Upon investigation, when playing with the selector shafts it noticeable that the indents for the ball bearing detents are not machined well, they have a rough edge to them. This can make selecting rather crunchy I think as they slide through the steel centre plate. Some minor fettling with emery on the slot edges & they slide through the main housing like butter (they were like crunchy peanut butter before)
Anyway some Pics
The Marlin Crawler Bearing plate fitted V the old worn out one
The detent slots that need fettling
The mystery of the gearbox revealed
Well as it happens they are the same gearbox as found in Supra Turbo's known as the R154, the R151 is different in ratios, input output shaft & end casings otherwise its the same. Allegedly the LC box has tougher thrust washers too. As I seem to munch a few of these R154 gearboxes on a regular basis (nothing at all to do with 520bhp & 450ftlb of torque of course) I've got to the stage where need to be handy at fixing them. So here's the latest one thats in the garage today.
Now there is a company in the states called Marlin Crawler who make a few upgrade parts for these & its well worthwhile fitting them for the minimal cost & its makes the boxes pretty much bombproof.
Things that break:
Centre Bearing Support Plate: this is made of cheese from the factory in R154's, they are pressed steel & flex under hard use, once stretched the bearing on input shaft wobbles about, if it gets really bad you can't select gears. Wose case it munches everything. Marlin Crawler make an upgraded part thats machined & its a lot lot tougher.
1st/2nd Gear Thrust Washer: These break up due to shear/shock on high performance stuff anyway, usually caused by rapid shifting under load. Allegedly the LC one is not made of cheese, its a different part number to the Supra one but is otherwise identical.
Things that are obviously a bit iffy: Upon investigation, when playing with the selector shafts it noticeable that the indents for the ball bearing detents are not machined well, they have a rough edge to them. This can make selecting rather crunchy I think as they slide through the steel centre plate. Some minor fettling with emery on the slot edges & they slide through the main housing like butter (they were like crunchy peanut butter before)
Anyway some Pics
The Marlin Crawler Bearing plate fitted V the old worn out one
The detent slots that need fettling
The mystery of the gearbox revealed