Hi...I just bought what I believe to be an 87 IROC 700R4. I want to install it in my 83 Z28. How can I confirm what I have? Are there some numbers or identifiers on the trans that indicate the vehicle it came from, the year of manufacture and that it is, in fact, a 700R4? Thanks, Gary.

 

Yes, there are some numbers. I forgot how to decode them, but on a 700R-4 they're in the passenger side, toward the rear of the pan, just above the pan.
As for what it is, 700R-4s use a basically square pan gasket. There's a bit of a concave curve along the front.

 

You'll want to check the number of splines on the input shaft. Older 700's were 27 spline (1984-1986) and the newer ones are 30 spline. The newer ones ('87-92) are much improved in many respects. So much in fact, that rebuilding the older style 700r4's isn't even worth it in my opinion. Also, if you pull the pan, the newer style trans have a crossover tube running across the valve body. If it has a golden rooster (the shifter plate with the gear detents that pivots with the shift shaft, it is most likely from an iroc. If it is plain steel color, it might not be from an iroc.

 

Thanks for your replies. I checked the oil pan and it's square with a concave in the front and the input shaft has 30 splines. I haven't had the pan off yet so haven't checked the cross-over tube. The shifter lever is steel. There is a number inside the bell housing: 8654732 so I think it's an 87 or newer trans. I appreciate your responses to my posting. Here's a photo of my 83. Thanks again, Gary.

 

'82-'85 was 27 spline, '86-up was 30 spline. '87 was better than '86, for sure, but '86 was 30 spline. I checked my '86 IROC-Z when I pulled the 305.

 

700R4 identification number... http://www.hotrodders.com/articles/T...ification.html

 

Thanks Louie, this was very helpful. I checked my trans serial number to learn that it is an 87 from a TPI 305. I appreciate your help. Gary.

 

The spline count is 27 from 1982 - 1984 1/2. Late 1984 & up is 30 spline. Starting in 1987 there were many updates throughout the transmission. Early 1987 used type I valve bodies, and the late 1987 & up, use the type II valve bodies. The late 1987 & up units are the ones to start with. Starting in late 1991 there were some minor changes made each year till its demise.

 

Thanks for your reply. I will check to see which type of valve bodies I have. I hope they're type II....!