74 Bronco won't go

[user456101]

Where to start .... 1974 Bronco was driving slow - wouldn't go more than 35 mph, then something popped and then no power to the wheels at all. Motor runs absolutely fine, but shift it into gear and nothing, absolutely nothing.  No rattle, no scrape, no crunch, no squeel, no nothing. Nothing moves underneath as far as I can tell.  The drive shafts are fine I think -  will turn 1/8 of a turn and stop.  Same symptom in both 4WD and 2WD but the shifter moves pretty easily between them - too easily?  Broncos are completely new to me. This is my soon-to-be son-in-law's, and he has never worked on it. Where to start? Pull off the transfer case and the transmission and take a look? Throw in the towel and have someone just replace one or both? What should I try first or what do I need to know before proceeding?   I think it is a pretty original (in-line 6cyl, 3 on the tree, drum brakes all around) vehicle.  If it makes a difference, he would like to switch to automatic transmission anyway - now a good time to go ahead and do this? He also wants to go 4-wheel discs.  He has had it 10 years, since he was 18, but has never made progress on it.  Now he has some money but not the time or space to work on it himself so I offered to do some footwork for him and I am handy with a wrench so I can work on it as well.

 

[Bully Bob]

Hi User., welcome..! 

OUCH..!   You didn't say anything about the clutch..?  Does the pedal work/feel the same.?

Try this.., with eng. runn'n.., depress the clutch pedal, put trannie in 1st gear,  slowly release clutch & listen for

any sounds/changes.

If none.., then with trannie in neutral, eng. runn'n, move the trannie gear shifter (slowly) toward 1st. or 2nd. gear,

(NO CLUTCH) JUST to the point of hearing gears touching.  IF you hear them touching, the trannie is likely OK.

If you don't hear gears touching, the issue is  in the trannie shaft &/or the clutch area.

After this.., don't do too much with eng. runn'n as something could catch & cause further damage.

Get all 4 wheels off the ground.  Eng. off, trannie in gear, transfer in 4-high or 4-low.  chock 1 front & 1 rear

wheel from turning.  Spin loose wheel by hand. If they spin & drive shafts rotate, the problem is likely in the

transfer case.  Possibly the in-put shaft has snapped.

(If you have Posi in the rear, don't block a rear wheel.)

Come back after these tests. :-B

 

[Bully Bob]

Also;

"Tactfully" ask future son in law if he did any "desert racer" maneuvers, i.e. "jumping the truck", etc.

These "stock" rigs are not meant for that type of treatment.

Has he kept fluids up in the trannie, transfer, & rear-ends..?

There's four shafts that one or more could be damaged.

Trannie input shaft, adaptor input to transfer case, transfer rear output shaft.

Also, the shaft from the trannie into the eng. crankshaft.

Note: Switching to auto trans is over $1000 in parts, not including labor.

This rig is likely due for a floor 3sp shifter & a "twin stick" replacement for the "sloppy" J shifter on the T-case.

Auto parts have books on this rig.

www.wildhorses4x4.com   www.tomsbroncoparts.com   www.jeffsbroncograveyard.com

These sites have parts catalogs, parts, etc.

 

[user456101]

Thanks.  Will do.

 

[Bully Bob]

"Bronco was driving slow - wouldn't go more than 35 mph, then something popped and then no power to the wheels at all"

BTW.., find this quite strange...!!  That's why I asked about the driving habits & maintaince.

Initially, I would assume something was binding up for some time. Then gave up or caused something else to give way.