Ford 4000 transmission

Tequila · Oct 1, 2011

Can a SOS be interchanged/replaced with an 8-speed manual transmission?

keh · Oct 1, 2011

I'm not an expert, but my cousin who has owned both is. You have to have an 8 speed transmission case, a new rear end, including housing, and a new clutch assembly and flywheel, as I recall. Don't remember about the axles and housings. Best solution is to find an 8speed with a bad engine, but not so bad you can't drive it and check the transmission condition, then put your good engine in it.

KEH

Fordfarmer · Oct 1, 2011

KEH has it right. (or you could gut the rear end and swap in new ring/pinion, etc. ...)
Somewhere I just saw an ad for a 4000 8-speed/rear end. (found it - searchtempest - St. Cloud MN craigslist)

Bob N.Y. · Oct 1, 2011

Are you talking about a 3 cylinder or 4 cylinder 4000? It makes a difference.

RodinNS · Oct 1, 2011

As long as you're dealing with a 3 cylinder chassis tractor... yes, you can make that change. As noted it will require the transmission and clutch/flywheel along with a rear axle change. Keep in mind that on 4000 S-O-S tractors the PTO is located in the transmission. In 8 speed tractors the PTO is located in the axle center housing... so you have none of the guts in the S-O-S center housing and they probably can't be fitted... So short answer... you need the entire back half and flywheel off a 4000 8 speed... or just find one with a bad engine and swap your engine.
It's not as simple as it first sounds.

A 5000 would be a very easy swap because the PTO is in the axle on all models although the rear end ratio may still be different...

Rod

Ultradog MN · Oct 1, 2011

As has been said you are better off changing the entire tranny and rear end. Here's the deal:
SOS has hyd pump on the side of the engine. Gear stick model has pump in the rear end housing. The same shaft through the tranny that drives the hyd pump also drives the pto. PTO on SOS and Gear stick are completely different so you would be switching a LOT of other parts besides the ring and pinion which on an SOS model is much lower speed. If you do buy a complete tranny and rear end you MUST also get the flywheel and clutch with it. SOS flywheel will not work.
Where are you located? My pal Kenny has a complete clutch, 8 sp tranny and rear end that he would like to find a junk SOS 4000 to put it into.
FordFarmer, that 4000 tranny and rear end on St. Cloud CL is Sold. I talked to the seller last night.

Tequila · Oct 3, 2011

thanks everybody on the 4000 info. Looks like I will stick with the sos.

Ford 4000 transmission

Tequila

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keh

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Fordfarmer

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Bob N.Y.

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RodinNS

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Ultradog MN

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Tequila

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