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Is there any diffrence between 1987 and 1985 5Y gearbox?
Hi,
I have 944 (118kw 160hp) produced September 1987 with 5Y transmission. My transmission needs replacement. By mistake seller sent me AGM trans from 944s, i wanted 5Y trans, so he proposed me a 5Y09105 which was found in 1986 model year UK car, i don't like it but i would like to get objective opinion is there any difference between late 5Y and the early from October 1985?
I'd have to check the workshop manual for any minor specific differences, but AFAIK they have the same gearing.
Regardless, it will definitely fit and bolt up properly.
October 1985 should be a "late" version (1986), but get a picture of it to be sure - it should have the black plastic plug for the speedometer pickup. Your car (September 1987 makes it a 1988, no?) needs a "late" transmission. The early ones from 1983-1985.1 don't have the speedometer pickup.
Last edited by FRporscheman; 07-12-2017 at 02:54 AM.
All 5Y transmissions are the same.
I don't see a AGM transmission, maybe he meant AGP? The ratios on that aren't that different, and would work just fine.
Correct, they are the same ratios, etc. There were minor production differences, some undocumented, but none would affect use. Around 85, Porsche did add a steel scattershield over the end cover (rear aluminum section) for what they termed "crash protection." You can easily swap from your '87 to the earlier gearbox if it's missing: two bolts. Good luck!
As far as I know, the AGP (and other S transaxles) uses the same stronger case as the Turbo and S2 transaxles, but the same weaker ring/pinion as the regular 8-valve transaxle. So, yes, it's stronger than a 5Y but not as strong as a Turbo/S2.
The gearing will probably give slightly better acceleration if you use the AGP transaxle. There's not much reason not to use it if you already have it on hand and it's in good condition.
As far as I know, the AGP (and other S transaxles) uses the same stronger case as the Turbo and S2 transaxles, but the same weaker ring/pinion as the regular 8-valve transaxle. So, yes, it's stronger than a 5Y but not as strong as a Turbo/S2.
The gearing will probably give slightly better acceleration if you use the AGP transaxle. There's not much reason not to use it if you already have it on hand and it's in good condition.
Looking at the ratios posted above, wouldn't the S be taller geared? I.E. the torque multiplication values (teeth of driven gear divided by teeth of drive gear) are smaller, but the FDR is the same.
The 944S ring and pinion are different from that used in the eight-valve normally-aspirated cars (eg, the 5Y version). The pinion shaft is longer, to accommodate the thicker gears common to the S/2/T gearboxes, and the pinion is a bit stronger. That said, the gearing of the 5Y and AGP is almost identical as measured as road speed.
Looking at the ratios posted above, wouldn't the S be taller geared? I.E. the torque multiplication values (teeth of driven gear divided by teeth of drive gear) are smaller, but the FDR is the same.
Whoops, yes, I think you're correct. Had a bit of a brain fart.
Ok, so APG also rattles but is the most silent out of 3 gearboxes installed on my car in the last 7 days so I leave it for now and go for holidays.
However, APG gearbox makes 944 souless, don't do it, as fast as my 5Y is fixed I'll put it right back where it was, unfortunately it will be at least 3 months. Ratios are worse than on the paper, additionaly I don't get Porsche engineers, why they made all the ratios from 1 to 4 longer and left the 5th the same as in 944 8v. They should leave 1-4 exactly the same and make 5th longer for more pleasent highway drive and top speed.
07-11-2017, 02:46 AM
Is there any diffrence between 1987 and 1985 5Y gearbox?
it makes knocking noises on neutral when warmed up. No, it's not a torque tube fault.
