Ok. Nearing the end of all my projects this year. Need to pick a trans oil to use for the up coming season(s?)
Car: 1987 Pontiac Sunbird Turbo GT Convertible
Engine: 2.0 OHC Turbo - LT3
Trans: Getrag/Munice HM282 MG1 - 5spee
Stock for my year the car calls for 5w30 oil for the trans. That's it. I had been running Castrol GTX 5w30 in it. In the year the trans was made they didn't really have synthetic oil availible, so everyone ran conventional.
It got me thinking maybe I should run a full synthetic in it, like Mobil 1 5w30?
Another guy I know runs Gear oil in it, synthetic, like 75w90.
Someone else told me later applications of the HM282, GM switched to using Synchromesh in them. GM uses Synchromesh in nearly all their newer manual transmissions, so it wouldn't suprise me. However, I can't find the specs on it, such as viscosity and construction...
So I'm all sorts of "hmm" now.. lotsa options, all of them probobly "work", just which one would be best? I'm more concerned about protection/longevity of the tranny vs "shift feel" but smoother shifting would be nice.
I have the 91 MG2 5 Speed and have run nothing but synchromesh in mine. In my opinion if GM called for 5W30 oil then thats what I would use. BUT, I would use the 5W30 Mobil 1 due to it increased lubrication, heat resistance, and longer life span. Just my 2 cents worth.
gm changed to syncromesh in the late 80s. my 1990 tranny says to use syncromesh, ive seen an 88 that said to use syncromesh. im in the middle of rebuilding my tranny, and the syncro/bearing kit is the same 86-92, and nothing realy changed in them.
now from my experiance, ive run 5w30 in this tranny, it worked ok, a bit notchy. i put in some manual tranny aditive, seemed to help and it actualy worked not to bad. once i put in gm syncromesh, the thing shifter like butter and i could actualy power shift with a lazy clutch foot. i would highly recomend using syncromesh in your tranny, even though it doesnt call for it.
it realy doesnt matter what you put in them, it will lube the bearings. the big thing is the syncros. if you put to thick of an oil in it, it will be notchy, because the oil cant be pushed out from behind the syncro fast enough. if you go too thin, you run the risk of burning up from lack of lube.
Sharkey, are you talking about HM282's here? Because GM did use a few other trannys on the v6's.. I'd be reffering specifically tot he MG2 derivitave of the HM282 which is the v6 bellhousing version of my same trans. GM also used the HM284 and NVG 550 IIRC on the v6 jbodies.
At the moment I'm actually thinking I'm going to use Redline MTL or Royal Purple Syncrhomax (likely the Sychromax, as it even says it's for trannies originally calling for 5w30 conventional oil). Both are full synthetic but spec'd for applications similar to mine. A fellow mod on a local forum I moderate, a hardcore Dodge turbo guy, and a great backyard mechanic that trust very highly, had this to say:
Quote:
DO NOT use synchromesh in a trans that was originally spec'd with motor oil.
A co-mod of mine on www.turbo-mopar.com used synchromesh in his A555 (Getrag trans built for Dodge.... VERY similar to yours, darn near identical in design) that was custom built with a quaife and a tall 1-5 gearset and a 3.50 FD and it did not provide the proper lubrication... 2nd gear and I think 3rd welded themselves to the transfer shaft and required 2 new cores (A555 and A520 with the 3.50 FD) to rebuild it. Quaife was ok cause its rated for that kind of fluid.
use the Royal Purple or the MTL or CONVENTIONAL motor oil. the synchros werent designed for synthetic (read slippery) motor oils and have a tendency to grind gears when shifting fast with those fluids. mine ground like crazy and then I switched back to 5-w30 conventional and everything is fine now.
Slasky has a A555 and he uses the RP synchromax and it works great for him (again, same vintage Getrag gears and synchros as yours...)... I might even switch to it sometime.
Makes you think eh? Hmm....
gm never used the 284 in a j-body, it was only used in luminas and grand prix 91-93 behind the 3.4l tdc motor. and for the record, the chrysler a555 is actualy the same guts as a gm muncie/getrag 284. now the 282 and 284 are simular in design, however they dont share any parts, and the 284 is way beefier. now the new venture gear (nvg) 550 was actualy just a renamed verion of the 282, but that had an internal slave cylender. it just like when they renamed the th125c, they called it a 3t40, but it was the same tranny
i am talking about the getrag 282. the syncros are all cloth type from factory, they work well with synthetic. in my rebuild kit, it had cloth 1st and 2nd, and brass 3, 4, and 5. as i said, the bearing kit is the same 86-92 (only reason 92+ is different is because the input bearing is different for the internal slave). the design didnt change. by 88, gm had figured out a specific fluid that worked well with thei manual trannys, so they speced it for everything.
As for the RP synchromax, its just a replacement for for GM synchromesh. I wondered my self if it was any better than synchromesh and had a local oil company rep call them to find out for me, he talked to Royal Purple and told me it was their replacement for sychromesh with additives to make it more slick for smoother shifting. What is the difference between the MG1 And MG2 trans anyway, just curious?
91z24audio wrote:As for the RP synchromax, its just a replacement for for GM synchromesh. I wondered my self if it was any better than synchromesh and had a local oil company rep call them to find out for me, he talked to Royal Purple and told me it was their replacement for sychromesh with additives to make it more slick for smoother shifting. What is the difference between the MG1 And MG2 trans anyway, just curious?
Uh... Sychromax is actually considerablly thinner then 5w30 motor oil, and synchromesh is thicker then 5w30 motor oil. They don'pt say anywhere on their site or white papers about synchromax being a replacement for synchromesh. They say it's a replacement for cars running ATF, or multi viscocity motor oil.. Of which synchromesh is neither...
Oh and the MG1 trans is the application of the HM283 for the 2.0 OHC turbo. It has different gear ratios, final drive, and most importantly the proper bellhousing with teh starter on the firewall side of the motor. The MG2 trans has different gear ratios and final drive and has the starter hole on teh front, for use on the 2.8 v6
i haven never heard anything called a getrag 283. mg1 and mg2 are the RPO (regular production option) codes used at the factory. now i know there are different ratios for the 282 transmissions, but they are still all hm282's. here is a list of them
Quad 4 Getrag
89
1st...3.50
2nd...2.19
3rd...1.38
4th...1.03
5th...0.72
FDR...3.61
1990
1st 3.50
2nd 2.19
3rd 1.38
4th 1.03
5th 0.81
Axle 3.61
1991
1st 3.77
2nd 2.19
3rd 1.38
4th 1.03
5th 0.81
Axle 3.61
1992-1994
1st 3.50
2nd 2.05
3rd 1.38
4th 1.03
5th 0.72
Axle 3.94
1991-1993 W41
1st 3.50
2nd 2.05
3rd 1.38
4th 1.03
5th 0.81
Axle 3.94
V6 Getrag
All years J and L body
1st 3.50
2nd 2.05
3rd 1.38
4th 0.94
5th 0.72
Axle 3.61
W Body V6
1st...3.77
2nd...2.19
3rd...1.38
4th...1.03
5th....0.81
FDR...3.61
Sunbird/Grand Am 2.0l turbo
1st- 3.50
2nd- 2.19
3rd- 1.38
4th- 0.94
5th- 0.72
fdr- 3.61
you can see that the only difference between the v6 and 2.0t is 2nd gear. everything else, including the fdr is the same.
Sharkey, I had a typo. I meant to say HM282, and wrote HM283. I fat fingered it heh.
As far as the gear ratios and final drive being different, I messed up. It's the automatics that differ v6 to sunbird turbo, and n/a sunbirds to the turbo version. The gear ratios / FD also differ between the MK7 n/a trans and the HM282 for the sunbirds as well
You're right, it' just the 2nd gear that's different between the MG1 and MG2. I don't even get why they changed it, maybe the casing change for the bellhousing required it? The difference isn't much... With my tire size at 6500 rpm redline, that's a 4 mph
difference in 1st gear.
that slight change in the gear ratio actualy keeps the turbo spooled, as oposed to dropping out of boost with the v6 ratio between gear changes.
