I was set to refill with ATF, until I saw this warning “5W30 oil. ONLY!” Seems to be some controversy here with people I talk to. Some say go ahead and use Dex ATF others say use 5W30 oil only. I also believe the factory fill was non synthetic. What should I refill with?

 

Is this really the .... w .... ww.... wo.... worl .... [ppppppppuuuuuuuuuuuuuuuuuuuukkkkkkkkkkkkkkkkkkkkkke] sorry, I just can't bring myself to utter that PIT Team, Total Quality, Six Sigma, 80s BUZZZZWORD without enduring SEVERE digestive upset ... aka 2nd design T-5? Look at the front countergear bearing, post a pic of it if you don't know how to tell.

 

You know, now that you mention it, I assumed it was a WC, but it's possible it's non-WC in '87.

 

I'm thinking non-WC but here's a video which shows the front around 36 seconds.

 

When you posted this instantly my mind said World Class, they had that in 87? I thought 88 was the first year. I didn't look into it any further then just that popping into my head though.

As to what lube it says 5w-30 right on it so I guess that is probably what you should put in it.

 

That's where I'm leaning. I wonder if 5W30 synthetic is ok? IIRC, the non-WC had some sort of an issue with synchros needing more friction, which is why they had gear lube. I can't imagine the factory fill not being conventional oil.

Also, I should probably change the title.

 

The non- w ... w ... wo ... [ppppppppppuuuuuuuuuuuuuuuuuukkkkkkkkkkkkkkkkkkke] ... yeah, the 1st design T-5, had brass blocker rings, same as any/all 3- & 4-speeds since the dawn of synchronzied transmissions. Therefore need the same lube.

Looks like in 87 the CAFE team won the closed-door cigar-smoke-filled conference room debate which was moderated by the "Finance" group. Since THE PARTS are the same as all those other transmissions for all those years, I'd use the same lube, as all of them did for ... what, half a century?

Which would be, gear lube. My go-to for the 1st design T-5 is (was) Mobil1 75W-90. Glad I don't have to deal with those POSs in my car anymore.

Assuming of course, that yours is the 1st design. I have of course no way of knowing that; it's too dark out now for me to see your transmission through my monitor.

 

Since the fluid currently in it is probably the factory fluid, you could drain it to see what comes out, and then decide what you want to put into it. I suspect ATF will come out. That's what was in mine, even though mine also has a 5W-30 tag on it.

 

The sticky at the top for T5s has pics to show you which T5 you have NWC/WC. In there people go back and forth as to what type of lube to use in it.

 

ANY lube (almost) is better than NO lube.

At some level it's hair-splitting to worry about which one is "original" or "right" or "best". Especially with a 1st design T-5; they leeeeeek SO MUCH out from around the front countergear bearing, the best thing to do, is KEEP EM FULL. With whatever you've got or can get quickly.

 

Screen shot from the above video. Looks a lot like a WC,

 

No kidding. Interesting.

 

Yeah, looks more like the 2nd design. So, not original to the car. Not that that particular detail matters all that much, beyond just IDing it.

2nd design T-5 has composition material on the blocker rings; same basic stuff as automatic transmission clutches. It also has tapered roller bearings with preload, rather than straight rollers with thrust washers and end play.

Use ATF. Best fluid for the blocker rings which are auto trans clutches in miniature. Of course, putting what the cap says in it, while maybe not in accordance with the TRANSMISSION MANUFACTURER'S recommendations (B-W's, not GM's), is probably OK enough; better than letting it run dry, if maybe not ideal.

 

You got better vision than I do.

 

Now you'll get an "interesting" from me, Chaz. Throughout all these years, it's never occurred to me to compare mine, so I just crawled under to take a look, and it's also like the WC in the bottom picture. And mine IS original to the car, 100% guaranteed.

With 1987 being the first model year the T5 was bolted up to the ~300 torque TPI engine, it would've made sense for GM to use the new "stronger" WC instead of the old "weaker" NWC. Or maybe the WC was used on V8s only, or it was a mid-late model year changeover leading into the full release for 1988. OR maybe the NWC doesn't look like the one in the top picture.

Edit: I was typing while Airwolfe was posting his pictures, and it appears that his picture of the NWC is probably the accurate one, and our NWC cases look the same across the bottom as the WC, so we can't go by that.

 

The plot thickens.

 

What was the manufacture date on your car?

 

There's a vin number on the engine and transmissions. Not hard to check if original.

 

If B-W ran out of the 1st design near the end of 88 MY production, then since they were already supplying the 2nd design to Frod & Xler, AND already had all the case dimensions and various other data for GM transmissions (and probably had the drawings and tooling ready to go), AND had a contract for the 2nd design for 89 MY production, it would have made sense for them to talk GM into taking the first run of the 2nd design a little early, rather than drag out the old tooling one last time. Especially since the 2 designs are absolutely interchangeable in the installation. I don't know that it happened here, butt that's the sort of thing that happens at the MY changeover. Either the last few leftovers get consumed à la the few 90 cars w 9-bolt rears, or they dip into the new ones if they run out.

And BTW you can see in my pics that somebody posted up there, that the 1st design has the bell housing flange only just barely surrounding the CG bearing and then leaves a gap between the BH and the bottom front of the rest of the case, whereas the 2nd design has the whole front of the case in that plane, with the triangular cutouts. The screen grab matches the 2nd design case butt is quite different from the 1st design.

 

December 1986 on the door jamb label. Invoice shows several dates, from the 19th through the 25th.