transmission

[86broncoman]

i have a 4x4 86 bronco with the 351w in it and a c6 tranny and will not go in to 1, 2, or drive but will go in to park reverse and neutral some one please help me i need to fix it its my only trasportation

 

[miesk5]

A quickie test for most common C6 no/late/soft shifting problems; Check da Vacuum Modulator and its Vacuum Line; it's at the back of the transmission.

also:

"...The different color bands indicate the diameter of the rubber diaphragm inside the modulator. The two COMMON colors from auto parts suppliers are PURPLE and GREEN. These are for CARS. TRUCKS like OURS REQUIRE the BLACK banded modulator, likely from a transmission shop or dealer. This is reguarding the mid/late 80's models, maybe more... Id venture to say any C6 with a slip in modulator. Again, PURPLE and GREEN are NOT the correct units to use, BLACK is the intended modulator as was designed for TRUCKS..."

Source: by MyFullSize (Andrew)

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Trouble Shooting Flow Chart

Source: by jasperengines.com via web.archive.org

"LATE OR NO SHIFT

Check vacuum to modulator - needs 18""

Check kickdown cable or switch

Stuck or dragging governor

Valve body..."

-

Ck shift linkage

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an Overview of the VM/kick down, etc by JGVABronco78

 

[Miss Kitten]

will the shifter physically not go through the forward moving gears, or is it when you put the shifter into one of the forward moving gears that the truck does not move forward?

if it is the latter and the shifter moves through the gears just fine, but the truck itself does not move then you may have blown the forward clutch drum.

if that is the case there is an upgrade availbe on the drum and it's supposed to be stronger (apparently, cuz i still managed to blow up the upgraded drum) but for every day driving should last you alot longer then the stock drum. the upgraded drum is actually from an E4OD

 

[86broncoman]

no the shifter goes through the gears but it just wont move in the foward gears

 

[Miss Kitten]

you may have the same drum issue that i did. unfortunately it means having to drop the enire tranny and paying for a rebuild