Yet another posi question

[DRIVEN]

Certainly can't hurt to soak it. I just figured since it was run, the friction material had already been saturated at some point. Either way, you'll probably be fine.
I've never had any serious issues with not having enough of the friction modifier additive in the way of broken parts, just some ugly noises.

Edit to add: At the last shop I worked we used Mopar additive in most everything, whether Chrysler, Ford, GM, or Jeep. No issues. It was cheaper by the case and meant only stocking 1 part number.

 

[84 W40]

If it was in storage for 20 years i would take it apart and inspect it and soak the clutches just to be on the safe side.

 

[Rktpwrd]

Certainly can't hurt to soak it. I just figured since it was run, the friction material had already been saturated at some point. Either way, you'll probably be fine.
I've never had any serious issues with not having the friction modifier additive in the way of broken parts, just some ugly noises.

Good to know, thanks. My experiences with posi carriers and differentials is somewhat limited. I can do bearings and seals, r&r ring gears, pull C clips etc, but I’ve never rebuilt a posi with the clutches.
Without the additive it should chirp and shudder when going around corners, much like driving a truck in 4 wheel drive on dry pavement. I’d just like to avoid that if possible.

 

[Rktpwrd]

If it was in storage for 20 years i would take it apart and inspect it and soak the clutches just to be on the safe side.

I’d like to try and avoid that if possible, but if the general consensus is that’s what it needs, then I’ll bite the bullet and do it.
Thanks.

 

[84 W40]

I’d like to try and avoid that if possible, but if the general consensus is that’s what it needs, then I’ll bite the bullet and do it.
Thanks.

Its not hard to rebuild those carriers but i understand. My concern is the spacers or shims between the clutches if there is any rust on them that had bonded to the clutches. If your friend was a Ford Tech have him take it apart.

 

[Rktpwrd]

Its not hard to rebuild those carriers but i understand. My concern is the spacers or shims between the clutches if there is any rust on them that had bonded to the clutches. If your friend was a Ford Tech have him take it apart.

Yep, that’s already what I’m considering doing. He’s pretty easy going and likely wouldn’t have a problem doing it. I’ll be right in there like a dirty shirt giving him a hand too trying to absorb as much info as I can. I like having the knowledge to do things myself, I don’t like having to rely on other people. Been let down too many times that way.

 

[pontiacgp]

As for the additive I use synthetic oil which does not need additive. I use this oil

https://www.mil-specproducts.com/Documents/1214_PDS27.pdf

 

[olds307 and 403]

I know one builder does not like synthetic for Clutch type posi. He is also of the old school to run 85W140 dino oil as his preferred gear oil. Most gear oils have the additive built in, read the bottle. As far as brand, I have used the Co-op 75w90 synthetic in my 8.25" Dakota with the clutch Trac-lok posi. I am thinking of Royal Purple or Penzoil 75w140, can't find the Amsoil severe gear 75w140 locally anymore, supposed to be the best and maybe picking up a tube of the CRC posi additive from Canadian Tire. I have some clunking here and there in the truck, could be other issues but the posi works when pushed. Even though I am fuel truck driver for Co-op, after having the piston rings stick on an Olds 350 running their DMO 15w40 oil, lifter noise with SN 10w40 and now a failing 8" ifs front diff in Dakota using the synthetic 75w90, makes me wonder how good their lubes are? They use the POA good base synthetic's, maybe just bad luck on my part. Either way, I need to call my local wrecker for a 97 to 99 Dana 35 ifs, so I can have posi, front and back.