what kind of gearbox would i have if i have an 89 sunbird turbo with 3spd auto. i heard that we have the F16 or F18 with either a close or wide ratio.. how do i figure out what kind i have without ripping my tranning apart?
1989 Pontiac Sunbird GT - LT3
those transmissions are in europe behind the lt3 engine (over there itrs named cet20dt or something like that)
your 3 speed auto is a TH125c. its the same auto used behind all j-bodies from the 1.8l ohv all the vay to the 3.1l v6. there are different versions of coarse. yours will be basicly v6 internals with a 2.0l bellhousing. im not sure of the RPO code for it.
so would the TH125c be stronger than the F16/18 or are they the exact same thing? and would i be able to swap them?
1989 Pontiac Sunbird GT - LT3
I don't know anything about the Euro trannys but your 125 should be a PPC code if it's
the turbo version. I believe there's a paper label near the top of the side cover but if that's missing it'll be stamped on the case somewhere.
Everyone bad mouths the 125 but they're actually pretty durable. I'd advise a shift kit and a cooler to help them live until you bite the bullet and have it rebuilt and modified. You'll also want to adjust the TV cable properly. There is no B&M type "Street and Strip" shift kit available. The ones that are available are what they call a "shift improver" which is designed to repair problems common to that tranny.
They're available through Superior or Gil Younger (who founded TransGo)
I know you didn't ask but in case you're wondering our torque convertor stall speed is about 2900 (it's like 2892) RPM and the axle ratio in all auto trans Turbo Sunbirds is 3.18.
Tony
Tony
1987 Sunbird GT turbo convert
Ported intake, Fiero 53 MM TB, 52 lb inj, ported and flowed head, tube header, Mitsu TD06, ARP rod
bolts/head studs, adj cam sprocket, 4" x 12" x 31" FMIC, Paxton AFPR, modified 125 trans/LSD
unit/3.42's, custom chip tuning, Alky Control Methanol injection
13.61 ET at 101.44 mph, 262 WHP/350WTQ
2009 Pontiac Solstice GXP roadster, 2.0 turbo w/GMPP exh, CAI and turbo upgrade, 290 hp/325 ft lbs
1969 Olds 442 convert
400 Eng, 200-4R trans, 3.73 posi, power everything, OAI
thx guys for all the info, i was planning on putting in a 5spd in my car with this 350fwhp kit. but i just wanted to kno if the 125 could handle the power or if i had to swap a modified F16/18 in. 2literturbo where did you get the LSD unit?
1989 Pontiac Sunbird GT - LT3
the 125 will handle the power if properly built, but for how long is the question. even the best 5 speed you can get wont last that long behind that kind of power.
your best bet for a 5 speed would be the getrag from a 2.0l turbo. its the only north american tranny that will bolt up and hold any sort of power. its actualy pretty decent, its realy the same tranny they put behind the v6's
yea i heard that the 125 could handle up to 380hp. so i wasnt really expecting the tranny to last long. and eventually i was planning on upgrading to a modified transmission eventually but im not holding any big bucks at the moment
1989 Pontiac Sunbird GT - LT3
http://www.engineered.net
That's where I got my LSD. It was recommended by Colin (I think he's HO660 or something close to that) on this site. He's had good luck with his too.
Tony
Tony
1987 Sunbird GT turbo convert
Ported intake, Fiero 53 MM TB, 52 lb inj, ported and flowed head, tube header, Mitsu TD06, ARP rod
bolts/head studs, adj cam sprocket, 4" x 12" x 31" FMIC, Paxton AFPR, modified 125 trans/LSD
unit/3.42's, custom chip tuning, Alky Control Methanol injection
13.61 ET at 101.44 mph, 262 WHP/350WTQ
2009 Pontiac Solstice GXP roadster, 2.0 turbo w/GMPP exh, CAI and turbo upgrade, 290 hp/325 ft lbs
1969 Olds 442 convert
400 Eng, 200-4R trans, 3.73 posi, power everything, OAI
I'd definately get a shift kit and tranny cooler. One person has already toasted a stock 125c behind a 3400 and they are only doing about 220ft lbs/190horse.
^^thats kind of wierd, did it have alot of miles on it? cuz i head they can undle up to 380horse. but yea im gunna do a 5spd swap, no auto for me
1989 Pontiac Sunbird GT - LT3
