I HAVE A 350 CHEV TRANNY WITH R4 on the top of the housing. what does it stand for? --lew
10-30-2002 06:20 AM
Are you sure it's not a 200 with an 4R? Never saw R4 on TH350 tranny..
11-01-2002 02:56 PM
The r 4 is used to identify that particular case casting. if they found the r4 casting was defective the could trace it back to the particular casting core and repair or replace it.The core is the mold they made that particular casting from at the foundary.I hope that answers you're question. bob
11-01-2002 03:23 PM
I think it is just a regular production option (RPO) code. Is it a 350C (lockup)? They started making them in 1980. If you are trying to identify the transmission you should check the 1-2 accumulator cover. This would mean it is a Buick built 350 69-72. Codes on the governor cover mean it is a Buick built 350 or 375B 73-81. If it is a Chevy built 350 the code should be stamped directly beneath the oil pan flange on the oil pan for 69-72 and either on the governer cover or pan for 73 and later. The second digit should be a number corresponding to the last digit of the year (ie 5 = 75 or 85). 82 and later Buick built 350Cs the code is stamped on a riveted plate last 2 digits being year. The only problem for all of these codes is that they can be removed and replaced. If you find a code and placement. I can probably decipher it. Not a VIN code though which is stamped into the case. The only way to truly know is to know the car or take it apart and inspect the parts. Hope this confusing info helped.