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4R70W Flexplate. Any suggestions?

kholding

Bronco Guru
Joined
Sep 6, 2010
Messages
2,209
Loc.
Las Vegas, NV
Time to get a flexplate for my 351W. I am bolting it to a 4R70W. Anyone here have any suggestions on what I need or the best place to purchase?
 

DEEPWOODS

Contributor
Bronco Guru
Joined
Jul 29, 2007
Messages
1,100
I think our bronco 28 oz. are correct . I have a 50 oz. explorer and a old 28 oz. bronco In the basement I will check for you
 

DEEPWOODS

Contributor
Bronco Guru
Joined
Jul 29, 2007
Messages
1,100
I checked and my old bronco 28oz. flex plate matches the 50oz. from the explorer the teeth and torque converter holes are correct. The old bronco is 28oz.so you can use on a 351w it if you have one.
 

rcmbronc

Contributor
Bronco Guru
Joined
Dec 15, 2003
Messages
2,725
Loc.
Tomah WI
Anyone have a pic of what a 28 oz flexplate looks like comared to a 50 oz. I have a flexplate that fits my 4R70W but not sure if it is 28 or 50.
 

DanWheeler

Bronco Guru
Joined
Nov 8, 2005
Messages
2,549
Loc.
Kirkland, WA
I looked at mine last night - its sitting in my parts pile. I think I took it off my 302 when I sold it because the buyer had a manual. It was on the 302 with the 4R70W. When I got my 5.0 I just re-used the flexplate that came with it.

so I'm pretty sure its a 28oz, 164 tooth flexplate. I'll try to take a pic tonight.
 

EricLar80

Bronco Guru
Joined
Jun 14, 2001
Messages
2,170
The 4R uses a 164 tooth ring gear and a 11.4" bolt circle, so you should be good to go with a C4 flexplate unless you have one of the odd years.

Eric
 

mattt

Bronco Guru
Joined
Sep 23, 2006
Messages
3,810
Anyone have a pic of what a 28 oz flexplate looks like comared to a 50 oz. I have a flexplate that fits my 4R70W but not sure if it is 28 or 50.

Don't take this as the bible, but I think I know how to discern a 28oz from a 50oz. In the pic, disregard what is written in Sharpie on the clean one.....both plates have a weight at about 9 o clock. The clean one also has a "window" in it that is 180* out from that weight...at around 3 o clock. My understanding is the 50oz plate has that window 180* out from the weight and the 28oz does not. So in the pic, the top one is 28oz and the bottom one is 50oz. I have a spare, new Pioneer FRA-205 flexplate I could sell $50....it is the correct one for 351/older 302 and C4, AOD, or 4R70W, 28oz, 164t, 14.23" OD, 11.xx~" converter pattern.

The other thing that people always ask about is how to tell the difference in offset between C4/AOD/4R70W and C6/E4OD flexplates. The second pic shows the difference in the torque converter mating surface offset. Look right where the ring gear meets the plate....one steps down, the other steps up. The one on the left is C4/AOD/4R70W...the one on the right is C6/E4OD.
 

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FSD

Jr. Member
Joined
Feb 14, 2011
Messages
100
I bought a flexplate from WH for a C4 auto, from what I've read and been told it works for the stock 302. I don't know 351W needs though. On a side not, did anyone ever find a block and inspection plate for the 4R70W?
 
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