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4wd binding up

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Old Jan 13, 2010 | 09:29 PM
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94 ranger tyson
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4wd binding up

hello all, new to forums. just put a salvage yard front diff in my 94 4.0 ranger. when i checked it, I drove it a couple of feet and it seemed to bind up. got a little worried and just disengaged 4wd. I think my rear diff is a 3.73. is it possible I got the wrong front one to match. The rear has tag to id but the front doesnt. please help!
 
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Old Jan 15, 2010 | 10:20 AM
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99F150
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If the tags are missing, only way to be sure is to count the teeth on the ring and pinion gears.

You can get close by jacking up truck and rotating a front tire while counting how many times the front drive shaft turns to one wheel rotation, then do the same in back.
Have tranfer case in two high with hubs locked and transmission in fourth gear for the 1:1 ratio.
 
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Old Jan 15, 2010 | 05:06 PM
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thanks 99 f150. Turns out the rear is a 3.27. Checked the truck I got the front diff off of and it is a 3.73 limited slip. I am going to get the rear from the truck I got the front from. Is limited slip is better than not having it? I was told it is better. Should the rears change out without any problems? Its coming off a 94 4.0 ext cab. Mine is a 94 4.0 standard cab. Any help would be greatly appreciated
 
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Old Jan 15, 2010 | 06:42 PM
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limited slip will allow both wheels to pull instead of just one. You will need the speedo gears from the donor truck too.
 
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Old Jan 15, 2010 | 07:55 PM
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I will be getting the intire rear axle. Are the speedo gears included in that? Where are they located?
 
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Old Jan 16, 2010 | 09:28 PM
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Installed rear today to match the front diff. All went well except will be looking for new driveshaft monday. Sore subject. Anyway, want to change fluids in front and rear diff. Can anyone tell me what fluids and how much go into a 3.73 limited slip diff. And does the front get friction modifier also? Also want to change fluid in 5 sp trans and transfer case.
 
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Old Jan 17, 2010 | 11:32 AM
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Traction Un-lock?

Originally Posted by 94 ranger tyson
Installed rear today to match the front diff. All went well except will be looking for new driveshaft monday. Sore subject. Anyway, want to change fluids in front and rear diff. Can anyone tell me what fluids and how much go into a 3.73 limited slip diff. And does the front get friction modifier also? Also want to change fluid in 5 sp trans and transfer case.
You only need the F/M in the rear dif. but i recently read a post where someone said they were putting F/M in the other gear cases to hopefully reduce wear in those components. I don't think it will make any difference as the F/M is engineered to assure that the clutches function properly. Without the F/M there would be more slippage in the clutch pack making the rear dif into a traction-unlock.
 
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Old Jan 17, 2010 | 04:33 PM
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Originally Posted by Moto Mel
..... Without the F/M there would be more slippage in the clutch pack making the rear dif into a traction-unlock.
Actually, I think you have it backwards. The friction modifier is called for to prevent clutch chattering, which would indicate that it makes the clutch slip easier.
 
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Old Jan 17, 2010 | 06:12 PM
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Thanks for all the helpful replies. Today I put valvoline 85-140 in rear diff with 4oz friction modifier. This info came from local dealer. In the trans and transfer case I put mercon5. I found this on a previous thread. Does all this sound correct? Right now I have 80w in front diff but am considering changing it because someone told me front diff fluid should match the rear diff fluid. Think this is necessary?
 
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