What size drift punch to use to drive in/out diff roll pins?

[Racer X]

As the topic states, what size drift should I use to remove and reinstall the roll/ tension/ spring pins in my stock MTX differential?

 

[Off Road SHO]

Anything smaller in diameter and softer than the diff carrier like brass or aluminum. A wooden dowel will work also.

Tom

 

[93rev2sev]

Why not run a tap and thread in some hardened steel screws? I bet they wont back out?

I'm sure this has been asked before but seems like good idea.

 

[AREA 91]

BE VERY CAREFUL!!! 1 Wrong move ='s SHO BOOM!

Change 1 roll pin at a time.

Drive the old roll pin out from the speedo gear side of the diff using a 5/32 drift punch. Be careful as you get real close to the speedo gear.

Drive the NEW roll pin from the opposite side of the diff with a 7/32 drift punch.

Measure the depth of the installed roll pins, to make sure they are centered with the pinion shafts.

Again be very careful, and change 1 at a time. If you use the wrong drift punch (too big) the diff will blow up.

Now is the perfect time to have the diff "reinforced"!!!

 

[SASHO91]

Why not run a tap and thread in some hardened steel screws? I bet they wont back out?

I'm sure this has been asked before but seems like good idea.

How will the diff get lubricated then?

 

[AREA 91]

The entire trans is "splash lubed" from the ring gear spinning in the fluid. The ATF fluid is then slung up the trans case following a channel that then feeds the lubricant funnels on the engs of the gear shafts.

 

[Racer X]

BE VERY CAREFUL!!! 1 Wrong move ='s SHO BOOM!

Change 1 roll pin at a time.

Drive the old roll pin out from the speedo gear side of the diff using a 5/32 drift punch. Be careful as you get real close to the speedo gear.

Drive the NEW roll pin from the opposite side of the diff with a 7/32 drift punch.

Measure the depth of the installed roll pins, to make sure they are centered with the pinion shafts.

Again be very careful, and change 1 at a time. If you use the wrong drift punch (too big) the diff will blow up.

Now is the perfect time to have the diff "reinforced"!!!

I'll be careful.

I don't know any competent machine shops in the area yet, and I don't feel like waiting another 3 weeks to get my car on the road and send out the diff for welding. I'll replace the roll pins, and go easy on "das droppen die clutchen".

On the pin install...

You said a 7/32 drift for install. If the replacement pins are 3/16, wouldn't a 7/32 be too large for the slight countersink? Or is the bore large enough to accomodate a 7/32 drift?

 

[TYSHO]

You said a 7/32 drift for install. If the replacement pins are 3/16, wouldn't a 7/32 be too large for the slight countersink? Or is the bore large enough to accomodate a 7/32 drift?

You can't drive it in with the same size or the chance of messing up the roll pin and opening it up is pretty huge, like 99.9% chance. You use the big drift to insert the roll pin from the opposite side of the speedo gear, as the opening is much bigger to allow for the larger drift. The drift should also be stopped by the smaller opening further down, and that is a stopping point I use with 1.5" long roll pins. Area 91's post is a great post on replacing them and what drifts to use, those are the same ones I use. If you're having a hard time finding the drifts in the correct length to reach all the way through, go to Lowes or Home Depot as both carry a set for $11-13 and they're coated blue. I believe they're Dayco if I'm not mistaken.

As for the reinforcement, it doesn't take that long to do. I can get one and turn it around in one day and have it at someone's door within 3 days of me receiving it. If you have a welder, I got the material and braces already made that I can ship out via USPS Priority 2 day. You can also have a machine shop or welder make you the brackets if they have the correct material, it's not all that hard. You really want it reinforced so you don't have to worry about the differential blowing when tracking it or just plain out driving it hard.