part numbers for 7/8 chain assembly

**02SSL32** · 06-12-2012

looking to see if one of u guys could help me getting ready to order parts for my transmision from gm. and looking to see if anyone knows the part numbers for gears and chain on the 7/8 chain kit. thanks

**BillBoost37** · 06-12-2012

Since you are asking about 7/8", I assume you are talking about the 4T60E trans?
There was no stock 7/8" chain ever available for the 4T65E. You would need to source at least the gears from a vendor. Then figure out which chain matches up to the gearset you have. There are two different chains.

**02SSL32** · 06-12-2012

yeah i know the 7/8 chain came from the 4t60 guess i just figured the gear set from the 4t60 would just work in the 4t65e.

**BillBoost37** · 06-12-2012

To my knowledge the reason the vendors charge so much is that the gears have to be machined.

**02SSL32** · 06-12-2012

yeah i failed to read the explanation of the parts included in the kits. hmmm think i might just go with the factory two chain from the 5.3 i read somewhere that its heat treated and i show through gm that its the same part that supercedes the original chain that came in my transmision

**Anthony Smith** · 06-12-2012

The GXP design chains had hardened pins but their still puny little bicycle chain looking pieces. The only way to go for a car that is modified or even stock and driven hard is a single chain conversion. The sprockets used for the single chain conversion are just 4t60 pieces with the thrust surface on the driven sprocket machined down and the holes for the reluctor drilled into the drive sprocket. I made my own out of core parts for free + the $40 for a brand new 15/16ths chain

**BillBoost37** · 06-13-2012

Anthony, is there a 7/8" chain also available from the 4T60, I thought that is where it came from. 15/16ths are known for snapping.

**Anthony Smith** · 06-13-2012

The wbody vendors generally characterize transmission chains by their width being either 7/8th or 15/16's but the width of the chain has a lot less to do with the strength than the pin type, being either rocker joint or round pin. The width measurement is just an easy way to tell them apart. Dont quote me on this but I believe the 15/16ths chain is the round pin style and came in 4t60's until 1993, the 7/8ths chain is the rocker joint style and came in transmissions from 1994 until they went to the dual "gemini" style chains in the 4t65's. Another issue is that the early and late sprockets for the two different chains are not interchangeable due to a different pitch between them. Basically a "7/8th" chain will not sit over the teeth of a "15/16th" sprocket.