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Hi, new member here and new to LS engines as well. I'm in the process of planning a 6.0 and T56 swap for my 1997 GMC Sonoma. It's a fun little truck with the 4.3, NV3500 5 speed, ZQ8 sport suspension and 3.73 truetrac, but it's pretty much reached its full potential with bolt ons and it seems a waste of time to add a cam, supercharge it, swap to a newer ECM to tune it, just to barely hit 300hp, plus the NV3500 isn't great for performance.
I've located a CTSV T56 for a good price, has the shifter already in the front position which will work, or come close with minor cutting, to the stock shifter location in the truck. The trans was pulled from another S10 with a mildly cammed 5.3 that I've got to hear/watch videos of running and driving. It's supposed to have no functional issues but the mileage is unknown and there are some visual issues with the trans. I don't know much about these transmissions to tell anything from the pictures so I wanted to post them here to see if anyone could give me any feedback.
known issues
1. Bellhousing was cut a bit to make bleeding easier.
2. Two of the sensors are either broken/melted/damaged - seller says both were not used in his install with a current performance conversion harness (I'll be using the same company for the harness). What are these sensors for?
3. Rear adapter for driveshaft might need to be replaced per seller - I can't really see why, is this a custom machined item or something I can order off a shelf?
4. One of the flanges was grinded down by someone prior to the current owner, he said it wasn't an issue with his install.
5. Input shaft shows some where, but I'm not sure what's an acceptable amount?
Here are some pictures, I'd love anyone with experience on these transmissions opinion on it.
Thanks
Last edited by 97Sonoma; 06-05-2018 at 09:48 PM.
Reason: added pics
First thing is if you dont already you'll have to run a custom cv driveshaft with that setup. The enlarged hole for the bleeder isn't a problem. Clutch appears to have seen it's better days. Not positive but that one sensor is likely the vss which you want for speedometer operation. How much is he asking for it and why did he pull it out of the vehicle it was in?
First thing is if you dont already you'll have to run a custom cv driveshaft with that setup. The enlarged hole for the bleeder isn't a problem. Clutch appears to have seen it's better days. Not positive but that one sensor is likely the vss which you want for speedometer operation. How much is he asking for it and why did he pull it out of the vehicle it was in?
Seller pulled out the harness pictures (harness had everything labeled). The Reverse lock out, VSS, back up lights are still in tact, as well as one other unknown sensor.
He had his installed in an extended cab with the 2 piece driveshaft. Mine will be one piece being a regular cab I imagine. Is a CV driveshaft considerably more expensive? Or could I swap this transmission to camaro tailhousing or something else that will give me the required slip.
The price is $1600. Most of the T56 I find for sale locally are around $2000, same unknown mileage or no way of verifying (at least ive seen video of this one running) and would need me to convert the shifter location still.
Iff-n it was me,, I'd buy it ,, and at very least I'd have a new input shaft installed and have the shop check the guts while they are at it,, I think the last one I dealt with the shop hit me about 800 to do a rebuild with the transmission carried in to them, I paid for a master rebuild kit for it (Bearings, sleeves gaskets) It turned out the only wear in mine was the input shaft splines and the bearings were showing some wear.. Since your other options are 2 grand, you buy this one with the intent to have it freshened up and your at 2400 with way less doubt on how it will work.. Most of the Aluminum five speeds wear the input bearings and counter shaft bearings out first, so I'd see what a local guy would charge for a go-through and freshen up on it.
Last edited by pdxmotorhead; 06-06-2018 at 06:02 PM.
Iff-n it was me,, I'd buy it ,, and at very least I'd have a new input shaft installed and have the shop check the guts while they are at it,, I think the last one I dealt with the shop hit me about 800 to do a rebuild with the transmission carried in to them, I paid for a master rebuild kit for it (Bearings, sleeves gaskets) It turned out the only wear in mine was the input shaft splines and the bearings were showing some wear.. Since your other options are 2 grand, you buy this one with the intent to have it freshened up and your at 2200 with way less doubt on how it will work.. Most of the Aluminum five speeds wear the input bearings and counter shaft bearings out first, so I'd see what a local guy would charge for a go-through and freshen up on it.
Thanks, I'm thinking that might be a good idea as well.
My only question now is if I'm getting myself into a mess when it comes to driveshafts with that CTSV yoke. If the drive shaft setup is going to be headache, expensive, or require me to swap out the tailhousings, that added with a $800 rebuild + parts, It's going to start approaching the $3300 mark for a new trans.
No matter what, your probably going to need a built to fit driveline.. in my neck of the woods thats 2 to 3 hundred bucks if you provide nothing but measurements..
I thought there was another application that used u-joints, you'd just need the output flange then,, You might just see what other vehicles used that transmission, some quick searching around with : CAMARO FIREBIRD 1993-97 DRIVESHAFT shows one on EBAY for 100 bucks or less.. Its a standard U-joint drive line.. NO CV, so a drive shaft shop can set the length for between 100 and 200 most likely.. It would require a little research but it looks like the output of the T56 is the same for both the Z28 and the CTSV, just the yoke is different, but I couldn't find an exact part number for the tail section and output shaft for the two.. Good Luck!
No matter what, your probably going to need a built to fit driveline.. in my neck of the woods thats 2 to 3 hundred bucks if you provide nothing but measurements..
I thought there was another application that used u-joints, you'd just need the output flange then,, You might just see what other vehicles used that transmission, some quick searching around with : CAMARO FIREBIRD 1993-97 DRIVESHAFT shows one on EBAY for 100 bucks or less.. Its a standard U-joint drive line.. NO CV, so a drive shaft shop can set the length for between 100 and 200 most likely.. It would require a little research but it looks like the output of the T56 is the same for both the Z28 and the CTSV, just the yoke is different, but I couldn't find an exact part number for the tail section and output shaft for the two.. Good Luck!
The only way around a cv two piece driveshaft to my knowledge is to do what i did with my cts-v t56. Buy a gto mainshaft and gto/f-body tail shaft housing. This trans is a mn12 and f-body stuff wont work except for the tail shaft housing.
Thanks guys. I guess with the price and how supportive the seller has been (any pics I ask for, and answering any question I ask, I trust him), I'm going to go ahead and pull the trigger on it. I still have plenty of research, sourcing and time to wait on the custom harness that I can probably figure out the rest by then, and worst case it's a good enough price I can resell it if it's not for me.
Pdx the problem with trying to run a slip yoke on the cts-v trans is there just isn't enough spline on the output shaft. Maybe only a 1 1/2". I think $1600 is a little high for the trans imo. For a $1000 I'd jump on it.
Pdx the problem with trying to run a slip yoke on the cts-v trans is there just isn't enough spline on the output shaft. Maybe only a 1 1/2". I think $1600 is a little high for the trans imo. For a $1000 I'd jump on it.
The cheapest T56 I've seen advertised around me was $1200 and it said it needed to be rebuilt. Most seem to be asking around $2000
The lower fitting looks like it might have been an oil temp sensor ? (and also drain bung )
And can you not get some sort of kit to adapt the output to a slip yoke ?
AT $1600...a trans that still doesnt fit perfectly, needs remedial work and could need internal work, it still doesnt sound mega cheap. Although obviously as a package with clutch, slave, BH price is maybe better if you intend re-using those parts. Certainly that clutch cover has seen better days...would you re-use it ?
Input shaft doesnt look perfect, but if the clutch disc moves smoothly on it, I probably wouldnt change it just for the sake of it, it doesnt look that bad.
When a brand new generic Magnum is around $3200...wont need any work, is already setup for a slip yoke and needs no internal work. It has to sound like a better option despite the added cost ?
Or any of the shaft makers could make you a shaft with a plunger style tripod joint which will allow fore/aft movement
I've been there and done this guys. I'm not speculating i know what I'm talking about. It's real ******* simple, if you want a slip yoke get a gto main shaft and tail shaft housing. Simple. Otherwise you can't run a slip yoke because of the limited amount of spline length. Doing this will likely add $200-400 in parts plus probably at least $400 in labor. Do yourself a huge favor and buy yourself a brand new Magnum t56.
06-05-2018, 09:38 PM
Help evaluating a CTSV T56 for purchase 
