Ok this forum seems to cover the 700R4 to TH350 swap religiously yet I've seen but 1 thread through 3 pages of searching that dealt with someone swapping a T5 out in favor of the TH350

I need to make sure I have all the bases covered before continuing on. Yes, I do realize that I will learn from mistakes and such but if I can avoid them then I will try my damndest too. I'm messing with my daily driver here and downtime is somewhat of an issue.

Just to cover base, here is what I gathered from the 700R4 to TH350 swap.

1. I get this kit
http://www.bulkpart.com/Merchant2/me...ore_Code=MDITP

2. I go to a junkyard and find myself a 700R4 tailshaft. Will it matter what 700R4 it came from?

3. Have my driveshaft lengthened 3 inches. I do not know the difference in length between a T5 driveshaft and a 700R4 driveshaft. What I gathered from the 700R4-th350 swap threads, if its a 6 inch tailshaft TH350, the driveshaft needs lengthening by 3 inches in order to be long enough to fit into the transmission.

4. Speedometer. I read that using the 700R4 tailshaft will allow the person to go without doing any modifications. But since this car is a T5 car, what, if any, modifications are needed to make sure the speedo is working correctly.

Thanks for any replies and advice I receive, I definitely will appreciate it.

 

there are 3 diffrent sizes of tailshaft on a TH350(I forgot the accual sizes), one gives the same length as our TH700r4, in which case you will not need any adapters or special legnth driveshaft, also the speedo hookup is the same as long as it's a mechanical speedo on the old and new transmission, you will need someware to bolt the tourque arm to, and a crossmember that has the tranny mount point in the proper location, this crossmember http://www.spohn.net/product.cfm?productid=1303 from Spohn fixes both problems, also remember to hook up the vaccume kickdown on the th350, also if the TH350 dosen't have the right legnth tail shaft, you will either need a new driveshaft to compansate or that adapeter (it seems too complicated....I'd just go with the diffrent legnth D/S)

 

Thanks, you know how much something like lengthening a driveshaft would cost?

Also, the speedo hookup, anyone have anything to add about that? If the T5 I have is mechanical and the TH350 is mechanical, shouldnt i be able to hook up the speedo to the TH350 without any problems?

 

the only thing you have to worrie about is getting the right speedo gears from gm for your rearend, find the ratio out and tell them you need the a speedo gearset for a th350 with you rear gears and they should be able to hook you up...as for the driveshaft....I have no idea...I'd say around 150-200, but it would be a guess.

 

You cant just bolt a different length tailhousing onto the TH400. Well you can, but it won't work. You need to change the tailshaft also. That requires tearing the whole tranny apart and swapping tail shafts. Not very hard to do on a TH350 (couple of hours of work), but I am not sure it is something you will be able to tackle. Just get a driveshaft from a Camaro that orginally had a TH200. All 1982 automatic equipped Camaros have them. I have one, but I am not sure I want to part with it. What is it worth to you?

Martin

 

sorry to revive a dead threat but i am doin the same swap and am a bit confused as well. so i will have to change the crossmember for the trans mount location? and what of the kit B&M 30299? is this useless to me here? and the five speed drive shaft is too long/short it too must be replaced?

 

I went from a t5 to a th350

It's not that bad of a swap. Basically you will need a torque arm kit from b&m to bolt the factory torque arm to the th350 tailhousing. It's $99 from summit. Then you will need a crossmember, you can either get a custom one from sphon or umi for ~$100 or get a used stock 700r4 crossmember and use the supplied bracket from the b&m kit above. In fact, I have an extra one you can have for free. Then you will need a shifter, I would deffinately go with a b&m console megashifter because it looks nice and comes with everything you need plus instructions, brackets, and a cable. It's ~$200. You will have to use a couple of home fabricated brackets to support the front of the shifter since there is a big hole where the 5 speed shifter used to go, it's not that bad though, I have some extra steel brackets you can have too with holes already in them. You will want to run a transmission oil cooler. I use the supercooler from b&m, it cost me ~$70 from summit. You will have to run your own tranny cooler lines. Some brake line coming from the tranny with rubber line going to the cooler will be fine. Depending on whicn th350 you get you may need to have the driveshaft lengthened. The "long" (medium) tailshaft th350 is the most common and is a direct fit, however if you have a short talhousing th350, you will need it lengthened. It cost me about $170. Keep in mind that your speedometer gears will most likely be off also so if you want your speedo to work right you will want to swap them before the tranny goes in.