I'm doing the auto to manual conversion,and i just got my manual diff(4.1) ,but is there way to make sure that i have a diff from a manual,i bought this part in the partstrader.The guy stated it was the 4.1 but,for all i know it could be a 3.9 rear end,And to pay my mechanic to install it and find out it to be 3.9 gears,that's my luck!I noticed some numbers on diff, if any one could tell me the difference, it would be greatly appreciated

 

first, look at the companion flange...the auto flange is thinner (plate) and the manual is thicker..this is due to the manual driveshaft being about 15mm shorter than the automatic.

the manual uses #"8" braces on the web gear while the auto uses #"7". The pinion on the auto is marker a different number than the manual and so is the webring stamping.

I know, I just took them both apart and am trying to rebuild it. how much did you pay for the diff?

 

I'm not sure what you mean by #7 and # 8 on the braces.Is that the size of bolt used. I'm also not sure the name of the parts either,like web ring stamping.I'm at work and can't look at it till tomorrow,but i think it has three bolts that go to the drive shaft,and the rest is in the casing.i can see where the axle goes.What am i suppose to look for,and how did you bolt up your auto drive shaft to it?Thanks

 

The brace stamps are inside the diff...you would have to take the diff rear cover and the 4 bolts that hold the braces to the web ring....please do not do that but that would be a way.

The diff has four bolts that attach to the driveshaft...where the driveshaft connects to the diff is called a companion plate...it has four bolt holes. YOU CANNOT USE THE AUTO DRIVE SHAFT WITH EITHER THE 5 SPEED TRANNY OR THE FIVE SPEED DIFF (unless you change the companion plate ont he 4.10) Look at your auto diff the companion flange is thin becasue the auto drive shaft is longer than the manual. The manual diff has thicker companion plate...

The drive shaft are very different from auto to manual....the splines/teeth whatever on the part that enters the tranny are different for the different trannys...the auto splines are thicker and chopped off more at the tips than the manual driveshaft...if you are doing the tranny swap, get the manual driveshaft.

Now if you are just using a 4:10 on an auto tranny...you would have to replace the companion flange on the manual diff...pretty easy with an airgum to remove the bolt and the companion flange will come right out....

The swap is a very involved...i guess to do it right. I have cleaned, wire brushed every nasty part I removed...my diff is repainted and rear hub is polished...but that is not necessary...recommend highly that you buy the manual engine harness...only thing I have left is to replace the guages...which I will buy new anyway.

 

Hey Silver,

I have a 4.33 ring and pinion that I will be dropping in my manual diff.

If ur interested let me know.

I like break even on the labor which I have no idea.

This may be a month or so until i get the parts off the car.

Make me an offer if ur interested.........

 

Count,,, Turn driveshaft flange (pinion gear) and count the axel turns....4.10 of pinion =1 turn= 4.10 gear. However if it only turns 3.90 times, you have a 3.90 to one rear gear,,, Carter

 

are the auto axles different from the manual ones?

 

no axles are the same