🔧 BUILD Upside-down M90 GTP build thread

[GTPpower]

I don't. Do you think that would help much?

 

[Turbocharged400sbc]

yup. the diff has no pressure lubrication like most gears and bushings, the only source it has is splash lubrication /initial lube from sitting and all the fluid fills the trans to just above the axle seals.

the only lube is bleed by on the plantary gears/sun gear.

burnouts sling all the oil away and leave you with nothing while you start to gall the pins and really heat everything up.

the 4t65e has output components that stay the same size/reduce in dia as it nears the diff. oil slung out from the controlled hydraulic leak known as a auto trans doesnt drain towards the diff.
the 4t80e on the other hand has output drive components that get substantially larger as you get to the final drive (and Tq load increases). so oil slung from its planets/clutches at least can "run downhill" towards the FDR planetary attached to the diff and at least bathe the sun and ring gear.

id still probably run a squirter if i planned to do burnouts ..... though the 80e allows for enough room that i believe i have a far better chance at fitting in a true LSD/mech locker.

ive already experimented with a welded 80e.....unfirtunatly a tight turn with 295 mt's on the front of the riv shreeeedead the inner cv....fortunatly being locked you could still drive it with 1 wheel drive

i am especially interested in trying my hand at a real cheap idea i saw once. but its kinda hokey. basically its a sprung snapon toolbox caster on a skate that one side of the front end rides on to and from the lanes/topend.

i aint gonna lie though, easy diff acess so we can change out the FDR planets/diffs is designed in. i believe my main headache/fuse ill find is the passenger stub shaft breaking

but yeah id weld em and rollerskate to the line if it ever becomes necessary. i dont think it will be. im sure that 10secnever would agree with me on the "cross that bridge when we drive it there"

 

[GTPpower]

For whatever reason, most tracks around here have a 90° turn into the water box, so I'm sure with slicks I'd snap something if the diff was welded.

Think I could tig weld a diff squirter in? I had a transmission once that had it brazed in. But I think I've only brazed once in my life, and that setup is out at the farm.

 

[Turbocharged400sbc]

You can braze using a TIG welder

 

[GTPpower]

Huh....I didn't know that. That's interesting. I think I may give it a shot.

 

[Turbocharged400sbc]

If I recall it's kind of messy aiming the discharge nozzle end the easiest way with that is to cut the tubing at a really sharp angle braze it closed and then grind it until there's a tiny opening but you can stick a sewing needle through

 

[Turbocharged400sbc]

If I recall its 3/16 tubing that was braised on to our governor line

 

[GTPpower]

That sounds about right from my memory. I have some pics of it. I should have kept that case.

Did some more reading on it. Tep claims that with his fluid recipe, the diff squirter doesn't help much because the fluid sticks much better to the diff gears.

 

[Turbocharged400sbc]

yeah, overkill is best kill, its all powdered metal near net forgings....gears are brittle.

 

[GTPpower]

I'll look at it some more and see how easy this would be in the car.

 

[Rdrnnr]

Whoa. How have I missed this thread?

 

[v6buicks]

Whoa. How have I missed this thread?

Now you have some reading to do. ? I'll have to send you a couple links to my favorite builds on here.

 

[Turbocharged400sbc]

Ain't nothing around here but some rusty ass Buick V6 powered stock junk with a bad spark plug wire.

 

[Rdrnnr]

Rusty bucks with bad plug wires are totally my thing tho [emoji23] idk what it is bout em but id rather play 3800 than ls any day

 

[GTPpower]

I've been holding off on this update for awhile, waiting for parts.

I wasn't sure what to do about the diff, then I happened to stumble upon a gmr torsen a guy was selling in Canada. Luckily, he was willing to go through the hassle of shipping it to me. After about 3 weeks, it showed up today.







It was installed in a transmission by prj about 10 years ago. I'm trying to see if it has the bronze (or brass... can't remember) washers installed. Anyone know if there should be a washer on each side of the planetaries?

 

[v6buicks]

Oh helllll yeah!

 

[Turbocharged400sbc]

They arent called planetaries they are worms and Spurs.

The worm gears put a lot of side loading onto the Spurs. That doesn't quite look like bronze but you're going to have to get a small magnet and test

 

[Rdrnnr]

Whatever witchcraft that is, it's beautiful.

 

[GTPpower]

They arent called planetaries they are worms and Spurs.

The worm gears put a lot of side loading onto the Spurs. That doesn't quite look like bronze but you're going to have to get a small magnet and test

There should be one bronze and one steel, correct? For each side of the spurs?

 

[Turbocharged400sbc]

I'm fairly certain that it should be bronze on both ends the worms wood likely provide thrust loads in both directions although maybe not....
only in one direction it would see loads for the most part....with you in reverse, The bronze washers wouldn't be as necessary in those thrust positions

 

[GTPpower]

Ok, I talked to Paul about it. He didn't think it looked like the bronze washers were in there. But this diff is the updated version that has the lube channels cut in, so that helps a lot. He did say that one needs to be on each side of the gear, against the gear, and the metal washer against the housing.



He also gave me the part number, so I got those ordered.



p/n for washer kit is K75906A

 

[Turbocharged400sbc]

I'm at the point now with my lathe and milling machine but I guess I could just put an ARB air Locker into a 80E differential half.... since gm hydramatic was so nice to make the planetary section it's own part, due to the 3 final drive ratios being done with the final reduction planetary.

The Ford 9in has some of the smallest and most compact Locker setups out there I just need to get up to the Janesville swap meet since I'm probably never going to see the Schaumburg drag expo ever again.

I can tell you this much from comparing the design of the GM Torsen with the quave I would go with the Torsen any day of the week they actually have thrust loads surfaces for the helical gears where is the Quaife the helical gears butt ends and just seem to kind of grind each other away

 

[GTPpower]

A quaife did just sell online for $750, but I don't know what kind of condition it was in. I had already bought this one too.

The day will come that I sell this and ditch the 65e, so if I can assist with your 80e locker project, don't be afraid to ask.

 

[Rdrnnr]

Ok now I see where this is goin...if anybodys ever gonna build an 80e fwd tranny I'll put 20 on it bein here and you two havin your hands in it tho.

This is the kinda stuff that makes me miss the days of runnin around forces old yorba linda shop gettin yelled at for pickin up girls and sneakin off at the track to have a smoke.

 

[GTPpower]

Finally got the right washer set for the diff. 3rd times the charm, I guess. That was way more difficult than it should have been. Update coming soon!