Swapping transmissions
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Swapping transmissions
I have a 2WD 1980 F100 with a 300cid, 5.9L, straight six and a four-speed manual transmission.
Several of the gears disengage/pop out of gear when I decelerate.
Since it will only get worse, I'm thinking about swapping in a new manual tranny.
Does anyone have any suggestions about which manual transmissions might make suitable and reliable replacements?
Thank you in advance.
Bran
Several of the gears disengage/pop out of gear when I decelerate.
Since it will only get worse, I'm thinking about swapping in a new manual tranny.
Does anyone have any suggestions about which manual transmissions might make suitable and reliable replacements?
Thank you in advance.
Bran
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Joined: Apr 2004
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Was your tranny standard 1st, and OD 4th?
Or low first, direct 4th?
Were you ok with the ratios?
Do you have a juice clutch or linkage?
The 5 speed OD options use juice clutch. M5OD or stronger ZF.
These have integral bells so you have to go juice clutch.
T-5 with adaptor will work, don't drop the clutch with a load in the bed.
T18 or T 19 for low geared 1st 4 speeds.
SMOD or SROD for OD 4 speeds.
Top loader Ford car trans, first is a little high and 4th direct.
These 4 speeds are bolt up and use your existing bell and clutch set up.
Or low first, direct 4th?
Were you ok with the ratios?
Do you have a juice clutch or linkage?
The 5 speed OD options use juice clutch. M5OD or stronger ZF.
These have integral bells so you have to go juice clutch.
T-5 with adaptor will work, don't drop the clutch with a load in the bed.
T18 or T 19 for low geared 1st 4 speeds.
SMOD or SROD for OD 4 speeds.
Top loader Ford car trans, first is a little high and 4th direct.
These 4 speeds are bolt up and use your existing bell and clutch set up.
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New User
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From: San Diego
1st is standard, not a granny gear. 4th is called overdrive & reverse is up and to the left. I'm ok with the ratios.
The clutch isn't hydraulic, it uses linkage. I'd rather not have to put in a hydraulic clutch, I want to keep it simple.
It sounds like, from your post, that (since my 1st isn't geared low) I should go with the SMOD or SROD. I still want to be able to haul moderate loads, so it sounds like the top loader Ford car trans might not be quite what I want.
How do I know what tranny I have currently? Is there a brand or tag somewhere on the tranny? I want to be sure that I don't install the same kind as what I have already.
What vehicles can I get a SMOD or SROD out of and how can I tell that it is a SMOD or SROD?
Thanks for putting up with all my questions.
Bran
The clutch isn't hydraulic, it uses linkage. I'd rather not have to put in a hydraulic clutch, I want to keep it simple.
It sounds like, from your post, that (since my 1st isn't geared low) I should go with the SMOD or SROD. I still want to be able to haul moderate loads, so it sounds like the top loader Ford car trans might not be quite what I want.
How do I know what tranny I have currently? Is there a brand or tag somewhere on the tranny? I want to be sure that I don't install the same kind as what I have already.
What vehicles can I get a SMOD or SROD out of and how can I tell that it is a SMOD or SROD?
Thanks for putting up with all my questions.
Bran
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Joined: Apr 2004
Posts: 34,505
Likes: 2,822
SMOD is a side-mounted linkage 4 speed OD tranny. The shifter is bolted to the tailshaft housing and uses external rods like the old days
SROD is a single rail 4 speed OD tranny. The shifter sits in a cast part of the tranny case and shifts with an enclosed rail, like most modern trannys. This unit is usually aluminum and is the weaker of the two.
Look under your truck and see what you've got.
I was quoted $500 offhand to rebuild mine, which is only making noise in 1st and 2nd off and on. These are seen as undesireable due to lack of low gear, gaps, weakness etc. You should be able to score one for under $500 at a yard.
Confirm what you've got first, then search. Might as well swap an identical unit if you are happy with it.
SROD is a single rail 4 speed OD tranny. The shifter sits in a cast part of the tranny case and shifts with an enclosed rail, like most modern trannys. This unit is usually aluminum and is the weaker of the two.
Look under your truck and see what you've got.
I was quoted $500 offhand to rebuild mine, which is only making noise in 1st and 2nd off and on. These are seen as undesireable due to lack of low gear, gaps, weakness etc. You should be able to score one for under $500 at a yard.
Confirm what you've got first, then search. Might as well swap an identical unit if you are happy with it.
Last edited by 85e150; Jan 1, 2005 at 12:13 AM.
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From: East Coast
Transmission Swap
I have to replace the flywheel in my other 78 ford with a manual 3 speed with a 300 in it. I also have a 1985 4 speed OD manual trans and what it looks like from your discrpition the SROD. Since I have to drop the trans to replace the flywheel would I gain anything (gas milage, wear & tear) if I put the 4 speed in?
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I think you'd get better mileage. You'd be able to travel at higher freeway speeds more easily. Be sure to consider all the details and possible changes that you might have to make. Also, get the stamped numbers off the sides of each tranny and referencesites like Motive Gear and 5 speeds to be sure you positively ID the trannys and what they're gearings are. After you positively know which model you have, which model you're considering switching in, and they're respective gearings, post that in the appropriate forums and see what people's inputs on the issue are. Good luck.
