4 speed trans in an 85 Fiero, originally an SE V6 173 (Page 1/1)
Biggest_of_A MAR 17, 04:50 AM
SC3800 swap done by owner previous to the one who sold me the car. It is a 4 speed, I assume a Muncie MY17?

The stamping on the case 14073796-GM CFM-8 does this number or the additional photos provide any further clues as to what I am working with?

Thank you in advance!

[This message has been edited by Biggest_of_A (edited 03-17-2020).]

Gall757 MAR 17, 08:31 AM
It looks like a M-17, which could possibly be the original trans. for that car.

Manual Transmission Identification with Pics

[This message has been edited by Gall757 (edited 03-17-2020).]

fierofool MAR 17, 08:36 AM
The webbing around the output shaft seals indicates it to be an 85 or 86 4-speed transmission. Another visual check is the presence or absence of cable attachment points down near the VSS. If it has those, it will be an 84.

Also, the plastic tag indicates the use of 5 w 30 motor oil. That was installed in the early transmissions. Later, a TSB was issued, replacing 5 w 30 and the newer cars came with Synchromesh Manual Transmission Fluid. Drain the transmission, get 3 quarts of Synchromesh and put 2.5 quarts into it. You will realize a much smoother shifting transmission. Pennzoil and other shelf brands are equivalent to the more expensive GM brand. Save some money.
Biggest_of_A MAR 18, 03:24 PM
Thank you for the valuable information in both responses. I have been operating under the assumption it is an M17. It does not have the cast in cable brackets of the 84 trans and instead has a bolt-on cable bracket. It does have the ribbed case.

There is unclear evidence in the paperwork that came with the car. Unlike the purchase of the SC 3800 and related parts, there is no clear receipt for purchase of the trans, but some entries from a salvage yard that could be, except also there are new purchase receipts for clutch, flywheel a clutch pedal and bushing was purchased in 09. Don't know if that indicates swapping in a manual trans because clutch and slave cylinders were also purchased, or if this was just the normal replacement of wore out parts.

So maybe it started out as automatic and they changed it to a 4 speed or perhaps the 4 speed is original.

Car is up on the lift now. I hope to check out the RPO sticker.
fierofool MAR 18, 07:24 PM
Does the steering column have the little ignition switch lockout paddle? If not, it was an automatic. Many who do the conversion don't change out the column.
Biggest_of_A MAR 25, 11:15 PM
Thanks, investigated further as per suggestions.

It is an original 4spd Muncie car as per the RPO sticker, I took a photo of this and decoded it using info available online. Also, It does have the lever by the ignition switch.

Will be changing the slave cylinder and oil pan gasket on the SC 3800, once the parts arrive next week, so will change the trans fluid then.