700R Auto Trans

Joined
Apr 15, 2007
Messages
2
I have restored a couple of fj40s recently and I'm wanting to do a V-8 conversion with a 350 TPI serpintine belts and a 700R transmission. I have been told a 700R can't be used because it is too long. Can anyone help with info? Thanks Eric
 
Joined
Feb 19, 2007
Messages
99
it is possible to run a 700r4 in a 40. i put a 700 in a cruiser using downey offroads adapter. requires a bit more work and costs alittle more than advance adapters but the adapter is shorter by around 5.75 inches and wont break . downeys adapter is 1" thick. A/A's adapter is 6.75 inches. i have seen a few of A/A's th350 adapters break and they are 5.25 inches in length. the downey kit requires a new front output flange and slip on the drive shaft. do it right and you will be pleased. hope this helps.
 
Joined
Nov 21, 2006
Messages
478
Location
H.B. CA
One of my friends used the Downey adapter behind a GM Vortec Crate engine (330 something horsies and somewhere around 400 LBS torque) in his '73 FJ40 with downey 4" springs, and 35 inch tires. Snapped the downey conversion shaft that was installed in the tranny (broke clean in two) This happened on the street with his foot in the skinny pedal pretty good, and just the slightest little bump in the road to give us a little bounce... BAM!! and then no more gears. had to walk back to my house and tow his 40 home... This was only a month or two after getting the thing running, and Downey did not honor their warauntee, and my buddy had to buy another $$ downey shaft and have the whole tranny torn down again... Really disapointed in Downey over that one. Got a close look at the shaft again not too long ago, and it snapped right at a big stress riser cut into the shaft right behind one of the splined ends- looks like a groove cut for a snap ring or something. If going the Downey route, make sure you know what you are getting into... see if they have redesigned the shaft, and how they will treat you when you come back with broken parts.
My friend's rear shaft was pretty short, but everything seemed to function when it wasn't breaking...
 
Joined
Feb 19, 2007
Messages
99
it is always good to hear everyones opinnions , i have not came across this problem but it is good to know. i have seen in the last 16 years at least 4 advance adapters adapter housings break , some from mild rollovers to broken pinnions , where the drive shaft hit the frame and the th350 adapter broke from the shock load put on it. i feel the longer the adapter the more chance of it failing, its only cast aluminum. now input shafts are another story.
 
Joined
Apr 27, 2005
Messages
379
Location
Hanford, CA
I have been using the Downey 1" adapter with TPI 305 with no issues yet.
My 40 is SUA with 37 MTR's stock axles, and 3 speed t-case. I know not what
most on this site would run but low budget, but getting ready to SOA and real
lockers. I"m happy with the adapter and hope to have a MC toybox soon.

Jerry
 

TJDIV

UP of MI.
Joined
Jan 28, 2003
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UP of Michigan
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www.roamwherever.com
I did it in my old 1970 FJ40 and it was a nightmare.

I would recommend seriously researching other options. I had it all done at a professional shop, all the tools, etc. Ultimately, if I were going to do it again I wouldn't have done it on a SOA rig and I'd have eliminated the fan for an electric fan and cut the radiator mounts and relocated it as much as possible.

I would have LOVED the rig if I had gone with a 5 speed manual or something similar. The auto really bugged me at stops too...I always went to N because it was always raring to go.

Up to you. I'd avoid it.
 

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