Guest TurboSedan Posted March 22, 2004 Report Share Posted March 22, 2004 can anyone tell me what an 'ATMM' memcal is from? it is from an '89 GP SE with a 5-speed but i'm not sure if it is a 2.8 or a 3.1? thanks joshua Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted March 22, 2004 Report Share Posted March 22, 2004 All early 88-89 5speeds should be a 2.8. Quote Link to comment Share on other sites More sharing options...
4spdz34 Posted March 22, 2004 Report Share Posted March 22, 2004 i belivie thats a 3.1 chip Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 22, 2004 Report Share Posted March 22, 2004 anyone know for sure? i want to try swapping my current memcal out for this one to see if my speedo becomes accurate again - but i don't want to do it if it is for a 2.8 since it might make my 3.1 run lean (??) for some reason the '90 3.1/5-speed memcal i'm using right now makes my speedo read about 11% too fast. it was fine when i had the '90 Getrag 282 in my car, but ever since i swapped in the '88 Getrag 282 the speedo reads too fast :?: if this 'ATMM' memcal is for an '89 3.1/5-speed it might fix my speedo problem? maybe i'll swap it in for a very short period and see what happens.... i've tried going to this site: http://www.cruzers.com/~ludis/p4xref.html#1227727 but i still couldn't find anything about an 'ATMM' memcal :? thanks for the replies - any more help would really be appreciated joshua Quote Link to comment Share on other sites More sharing options...
rudefyet Posted March 22, 2004 Report Share Posted March 22, 2004 did you ask over at 60degreeV6? Ben a.k.a. SappySE107 has a nice little database of MEMCAL #'s maybe he can help Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 22, 2004 Report Share Posted March 22, 2004 I thought that the 5-speeds were only available with the 2.8s (and 3.4s). From the cars I've seen at the wreckers (automatic) the 1990s got the 3.1. On the site here it says that the 3.1 didn't recieve a 5-speed. http://w-body.com/firstgen/grandprix.html whatever chip you have make sure you got the matching VSS. the 3.1 did recieve a Getrag 282 in '90, *maybe* even some in '89 i'm not sure :?: i know some NA 3.1 '90 Grand Prix STEs came with a Getrag 282. also, the 2.8 was discontinued in early '89, and the 3.4 (and Getrag 284) wasn't available until '91. i bought a '90 3.1/Getrag 282 combo from brian89gp on this forum a couple years ago - he said it was from a Grand Prix. the memcal i'm using right now was from that car too. i tried swapping the VSS that was in my '90 Getrag 282 into my '88 282 - no change at all...it even had the same part # on it. apparantly the difference is the exciter ring inside the differential (which gives the VSS its signal), that's the only thing i can think of. i guess earlier cars had a different memcal to make up for a different exciter ring?????????? i wish i knew.... the speedo used to be dead-on accurate with the '90 Getrag 282, but the '88 Getrag 282 fucked it all up. i'm using the same tires, the same wiring harness, same ECM/memcal, the same VSS as before...the only thing that changed was the tranny itself. i'm beginning to think the only way to fix this speedo problem is to buy equiptment and learn how to use gmpcm.com software, then go in and edit the speedo function in the chip....or swap in the extra '89 282 i have and hope that works.... maybe the '88 282 is the oddball one since it was used with MAF systems. can you tell this speedo problem is driving me nuts? joshua Quote Link to comment Share on other sites More sharing options...
brian89gp Posted March 22, 2004 Report Share Posted March 22, 2004 I thought that the 5-speeds were only available with the 2.8s (and 3.4s). From the cars I've seen at the wreckers (automatic) the 1990s got the 3.1. On the site here it says that the 3.1 didn't recieve a 5-speed. http://w-body.com/firstgen/grandprix.html The site is wrong. The switched the type of VSS sensor and pickup the Getrag uses in the 89-90 area. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 22, 2004 Report Share Posted March 22, 2004 i went out to my garage and compared the exciter ring on my '90 and '89 282s - they look the same but then again i didn't measure the distance between the 'teeth' or anything. i didn't check the ring in my '88 282 - i probably couldn't see the ring anyway even with the VSS pulled out since it's in the car right now. joshua Quote Link to comment Share on other sites More sharing options...
Corpse Posted March 22, 2004 Report Share Posted March 22, 2004 I remember reading that in 89 they changed the VSS in the HM282. but, i thought that it had read that they also changed the VSS unit to a different style of pickup... I know I read that, a long time ago, could be incorrect though. -Dave Quote Link to comment Share on other sites More sharing options...
4spdz34 Posted March 22, 2004 Report Share Posted March 22, 2004 maybe u got a different final drive in that trans Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 22, 2004 Report Share Posted March 22, 2004 hmmm, i guess it could have a different FDR, but i've always read that all V6 Getrag 282s had the same FDR. the VSS that i took out of my '90 282 was exactly the same as the one in the '88 282. same part # even. i also put the VSS from the '90 282 into the '88 282, and the speedo still read 11% too fast. it would be nice if the '89 5-speed memcal i have would fix the problem, but i doubt it will be that easy. joshua Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted March 22, 2004 Report Share Posted March 22, 2004 Didn't u get the 88 trans out of a Corsica? If so I thought they have a different than a W-body. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 23, 2004 Report Share Posted March 23, 2004 Didn't u get the 88 trans out of a Corsica? If so I thought they have a different than a W-body. nah it came out of an '88 Grand Prix. i used to have an '88 Corsica with a Getrag 282, but that was about 10 years ago. i destroyed that tranny (synchros). people say the Getrag 282 is strong, but i've somehow managed to blow 2 of 'em without even beating on them :? joshua Quote Link to comment Share on other sites More sharing options...
Corpse Posted March 23, 2004 Report Share Posted March 23, 2004 Well MR. Trannykiller, I think you need to be nicer to your HM282's. But, nonetheless, I'm sure you already know but, always make sure to use Syncromesh type fluid. -Dave Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 23, 2004 Report Share Posted March 23, 2004 i dunno - i've kinda lost faith in them but i still like 'em. it's not like my 215,000+ mile 3.1 is putting out a whole lot of power. i've always used GM Syncromesh. i blew the '90 282 at 210,000 miles, but it had been rebuilt once before i got it at 164,000 miles. the tranny fluid looked perfect up until the day it blew. i was just driving along normally at about 30mph in 3rd when it started making some horrible noises. it got worse FAST and the fluid turned black. i was loosing gears completely one by one. when i finally removed the trans i found big chunks of alumnium blown out of the bellhousing area. my brother said it looked like the intermediate shaft carrier bearing went but i really don't know. i still have the trans so i'll try to get some pics of the carnage. the '88 i have in the car now has about 115,000 - so far it's been great (knock on wood). well, it's great besides the speedo being way off thankfully i have an extra 282 sitting in my garage that i can put in the car if (er...when) this one goes out. joshua Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 24, 2004 Report Share Posted March 24, 2004 i just went out and pulled the VSS out of the '88 Getrag 282 in my Cutlass. surprise surprise: the exciter ring's teeth are much closer together compared to the exciter rings in my blown '90 Getrag 282, and the '89 Getrag 282 in my garage. this obviously means that the VSS will pick up more pulses per mile and is the reason my speedo is reading too fast. the VSS sensors themselves appear to be exactly the same for all three 282s. so...if anyone here is planning on doing the 5-speed swap, try to avoid using an '88 Getrag 282 unless you are also using a 'matching' '88 MAF 2.8 engine and it's respective memcal (or swap the exciter ring if that's possible). since the 'ATMM' memcal i have is from the same car my '89 Getrag 282 came from, i already know it won't work to fix the problem. i will be using my '89 Getrag 282 once i get the TGP engine ready to install in the car....not sure what i will do with my '88 Getrag 282. i wonder if editing the speedo function in the chip would even work to remedy the problem? oh well. until then i guess i'll have to live with it. thanks for all the replies. joshua Quote Link to comment Share on other sites More sharing options...
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