1951 Pontiac Chieftain

[AMCrebel]

This is great. I have long been terrified of gearboxes - not even sure how manual ones work beyond a simple understanding of it being different paths through different cogs - no clue how the selectors work. Way off topic (sorry) but my old Volvo 240 had an early 5 speed box. They bolted on an extra casing with the extra gear in to the 4 speed - weird and a bit wank. Later models got a properly redesigned 5 speed.

Back on topic - I appreciate the clear and detailed explanations on here - great thread.

[PhilA]

This is great. I have long been terrified of gearboxes - not even sure how manual ones work beyond a simple understanding of it being different paths through different cogs - no clue how the selectors work. Way off topic (sorry) but my old Volvo 240 had an early 5 speed box. They bolted on an extra casing with the extra gear in to the 4 speed - weird and a bit wank. Later models got a properly redesigned 5 speed.

Back on topic - I appreciate the clear and detailed explanations on here - great thread.

Yup, the JB3 gearbox in my Renault is a 4 speed with an afterthought stuck on to make it a 5 speed, fairly common in the 80's when it mattered if you had 5 gears.

[Hooli]

5th is over an overdrive gear (4th says at 1:1 & 5th goes above that) so a bolt-on bit around the output shaft is a sensible way of doing it.

[PhilA]

5th is over an overdrive gear (4th says at 1:1 & 5th goes above that) so a bolt-on bit around the output shaft is a sensible way of doing it.

True, but the most-used gear sitting outside the case under a little baked bean can doesn't make for quiet cruising.

Phil

[PhilA]

20201120_171852.jpg (2.11 MiB) Viewed 2686 times

Cleaned the body of the other horn down.

20201120_172321.jpg (1.87 MiB) Viewed 2686 times

First couple coats of paint on that side. Gotta do the lid next.

Phil

[PhilA]

20201121_123558.jpg (1.34 MiB) Viewed 2664 times

My loupes arrived. I'm going to pull the gearbox apart again.

Phil

[PhilA]

20201121_160446.jpg (931.63 KiB) Viewed 2647 times

20201121_160906.jpg (1.47 MiB) Viewed 2647 times

Inspected valves, found a couple burrs. Tried to get rid bit it's really quite worn. I may have to pull it apart again because I didn't want to go hog-wild and cause more trouble than I was fixing.

Phil

[paulplom]

Could a machine shop repair that? I imagine it'll be a pita sourcing a new one.

[Hooli]

Looks ready to be trimmed down and a collar fitted to resize it?

[PhilA]

Could a machine shop repair that? I imagine it'll be a pita sourcing a new one.

Possibly, but I can get good used ones- they just aren't particularly cheap.

The design of this is intricate and really non-straightforward. I would worry they'd screw it up. I can probably get this one working acceptably with a bit more work while I save up.

Phil