Tranny problems upon reinstallation

[Michael]

I finally reinstalled my engine back into the engine bay. It’s a Mark IV BBC, now displacing 461 cu in, with a Doug Nash 5-speed (similar to Richmond 5-speed) transmission into a ’78 280Z, Centerforce clutch, Ram aluminum flywheel, McLeod hydraulic throwout bearing. The transmission has been sitting for 5 years.

 

Two problems...

 

1. The shifter appears to be in neutral, but I can’t shift any gears; the shifter simply won’t budge! The clutch is hooked up but not bled yet, so it’s not functional.

 

2. The input shaft is spinning OK (I checked before connecting the transmission and engine) but the output shaft is not! Torque to turn over the crankshaft (spark plugs not installed) is about 30 ft-lbs – same as it was without the transmission installed. Connecting the driveshaft makes the car immobile. Turning over the crankshaft will not turn over the driveshaft.

 

This is an externally-shifted transmission. I checked that there’s no interference between the trans tunnel and the shift rods (trans tunnel has some mods). By my estimation, the transmission is nearly (but not completely) empty of gear oil; most spilled out through the tailshaft when the engine/trans were pulled in October 2000.

 

So, given the above – any hunches as to why would a transmission “lock up†this way?

[Mikelly]

This same thing happened on my brother inlaws brand new Richmond transmission when we installed it in his (Now gone) Olds 442. What ours turned out to be was shifter/ linkage related. We had to completely redo the alignment of the external linkages because they were binding. We replaced all the bushings that the linkage pins ride on, and reset the detent on them and were able to shift the car into neutral and every gear. However, I don't recommend trying to force it. We thought that maybe the tranny was caught between gears. locking up the output shaft.

 

Mike

[Trevor]

I've got a mental picture of the guts of my '66 Mustang's toploader 4-speed, not that that helps, but I think what happened is your shift arms / linkage is engaging 2 gears at once. I happened to me several times with the old worn-out factory shifter, until I replaced it with a Hurst Competition 20 years ago. The external rods (there are 3 right? 1&2, 3&4, 5&R) and arms have 3 positions gear - neutral - gear. Make sure all 3 are in the center / neutral position, and that all 3 of the shifter lever arms are all in the center neutral position then re-connect the rods.

I think you can discount the 5th gear (Isn't this a non-overdrive 5th?) lever position as the suspect, since the input shaft in spinning freely.

[Michael]

You guys are great! Indeed, the transmission was stuck in two gears simultaneously. Evidently what happened was that one of the shifter arms got bumped when the engine/transmission were reinstalled. Working the shifter (Hurst) didn’t help, but wiggling the 3/4-gear lever arm popped it back into neutral. And then both aforementioned transmission problems magically went away! BTW the shifter rods were custom-resized/bent when the car “ran†the first time, in August 2000.