3spd w/ OD shift problem, possible upgrade?
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Senior User
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From: NC
3spd w/ OD shift problem, possible upgrade?
Ok, so, I have a 1987 F-150, 4.9L, 3spd w/ OD manual transmission. Transmission will not shift into 3rd gear with engine running, however if engine is stopped, will shift into 3rd no problem, at which point engine can be started and vehicle will pull in 3rd. I'm basically new to transmissions, but the little bit I know is leaning towards a synchronizer? Maybe? I don't know.
Whatever the problem is, it's something I want to try and fix/upgrade myself. I have always wanted more gears, so I thought about upgrading to a 5spd manual, if whatever this problem is would require a rebuild/replacement. However, I don't know what kind of cost or other parts I may need.
Even if I deem the 5spd conversion too expensive/complicated, I will probably find a junkyard 3spd/OD to rebuild, then just swap in, in order to keep truck on the road and also to make it less of a rush to get the transmission fixed. Any help, thoughts, ideas, pointers, tips, basically anything is appreciated.
Whatever the problem is, it's something I want to try and fix/upgrade myself. I have always wanted more gears, so I thought about upgrading to a 5spd manual, if whatever this problem is would require a rebuild/replacement. However, I don't know what kind of cost or other parts I may need.
Even if I deem the 5spd conversion too expensive/complicated, I will probably find a junkyard 3spd/OD to rebuild, then just swap in, in order to keep truck on the road and also to make it less of a rush to get the transmission fixed. Any help, thoughts, ideas, pointers, tips, basically anything is appreciated.
Lead Driver
Joined: Nov 2002
Posts: 9,556
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From: Concord, NC
I swapped the same transmission out of my truck and installed a ZF 5-speed from an F250. You will need to change the hydraulic line for the clutch, a new slave cylinder, change the floor pan insert, the transmission cross member and you'll need to have your driveshaft modified to the correct length. Depending on which speedometer drive gear is in the transmission, you may need to change the driven gear on the VSS too. You will want to swap in a transmission from an 88-91 truck - anything after that will not have provision for a mechanical speedometer drive.
Can you double clutch and rev-match to get it into 3rd with the engine running? I had trouble downshifting to second with my old transmission, but a double clutch and a blip of the throttle would let it fall right in.
Can you double clutch and rev-match to get it into 3rd with the engine running? I had trouble downshifting to second with my old transmission, but a double clutch and a blip of the throttle would let it fall right in.
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From: NC
On my way home last night I figured out how to maneuver into 3rd, I either have to go past third, making sure to kind of scrape by it, like I'm moving something out of the way, and then go into 3rd, or I have to drop into OD and then back up into 3rd. From what little I know, sounds even more like a synchronizer, correct?
I didn't think to mention I have a 4x4, will the ZF from an 88-91 mate up with my transfer case just fine? Also I have a 4.9L L6 engine, will the ZF mate with that?
I didn't think to mention I have a 4x4, will the ZF from an 88-91 mate up with my transfer case just fine? Also I have a 4.9L L6 engine, will the ZF mate with that?
Lead Driver
Joined: Nov 2002
Posts: 9,556
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From: Concord, NC
It could be something worn in the shifting mechanism if it feels like you are moving something out of the way.
There are three ZF cases, one for small block engines, one for big block engines, and one for diesels. You will need to get the small block version to bolt to your 4.9. I have a 4x2 so I don't know for sure about the transfer case, but from what I have read, most will swap directly to the ZF. You can also disregard the part about the speedometer drive gear, as those are in the transfer case on 4x4 trucks. You'll have to measure for the driveshaft too - I don't know how the length of the 4x4 version of the 3+OD compares to the length of the 4x4 ZF.
There are three ZF cases, one for small block engines, one for big block engines, and one for diesels. You will need to get the small block version to bolt to your 4.9. I have a 4x2 so I don't know for sure about the transfer case, but from what I have read, most will swap directly to the ZF. You can also disregard the part about the speedometer drive gear, as those are in the transfer case on 4x4 trucks. You'll have to measure for the driveshaft too - I don't know how the length of the 4x4 version of the 3+OD compares to the length of the 4x4 ZF.
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