studlybilly

Hello, I've just acquired a 94 Z28 that shat out its 4L60E (figures since I hear there notorious for it). I've done some research and see that yall (other F-body owners) are surpassing this tranny with TH350's and 400's. I intend to do heads/cam/stall/12 bolt rear geared and posi'd (I will be spraying it). I need a tranny suitable to take abuse, but not pro-mod punishment lol. I'd like a 700R4 for the 4th/OD gear, and understandably they seem more reliable than 4L60E's (then again I hang around a TH350/400 crowd lol). I'd rebuild it with red clutches, shift kit and redo the valve body, also swap out the oil pump. I guess with this novel I'm asking for some insight? What all is involved in the conversion? Mostly being concerned with the speedo and computer problems... I spose I'm considering the overdrive/ final gear for the from a roll races

Thanks,
Billy

jxaxsxoxn

iTrader: (2)

I don't see the point. A 700R4 has the same internals as a 4L60E except for the valve body, pump cover, and a few other small things.
You'd be swapping out the oil pump with the one out of a 4L60E.
You could swap parts out of a 4L65E into either a 700R4 or a 4L60E and have a stronger trans.

studlybilly

Ok then, I wasnt to sure on the 700R4. Are the TH350 and TH400 the same eaze to install? Or does one possibly bolt in as oppossed to the other? Sorry just trying to cover all bases before investing into something that wont work.

studlybilly

Well after researching some more it seems I've narrowed my choices to the and TH400 (banking on the Th400 from hearing of its strength factors). With this i've developed a few questions that I'm researching for. I'm banking that I can use my stock flexplate with the swap? However, I'm unsure of whether I buy a TC for a Th400, or is there a key TC matching the splines thats a popular choice? Last and foremost, how much of a bolt in swap is this, as in saying will I be able to use my 4L60 xmember or will I have to alter/fabricate it?

Through reading the Th400 FAQ thread (god that thread was a brilliant idea to bad I didnt see it until after I posted my first question), I saw that it is possible to retain the stock shifter and I do plan to do so. I'm not going reverse Manual valve body as I will regularly drive/downshift this car and dont feel like rebuilding valve bodies yearly. I will simply use blue/red friction clutches, a shift kit, and a new pump.

Last and Foremost, I would love to keep my speedo and in check at that. I spose I should ask if in 94 they had a speed sensor in the trans and rear end or just possibly the rear end? If both then I'll need to look into a reluctor ring/speed sensor setup in the tail shaft. Any insight/suggestions are greatly appreciated at this point

93LS1RX7

iTrader: (8)

Check out a 200-4r from a Grand national. That is what I have behind my ls1 and it works great.

The 400 and 350 are great because they are cheap and strong but they have no overdrive so if you drive the car a lot it will get old going down the road at 3500rpm.

studlybilly

Are they the same at the 200R4's that were put behind S10's etc.? Or is there a distinct difference being behind the grand nasty? (I'd guess because I heard 200R4's are weak?

93LS1RX7

iTrader: (8)

BIG DIFFERENCE.

The 200-4r's that were behind the Monte Carlos and S-10's etc are weak.

The GN 200-4r are much stronger, have much better pumps etc. They wont last forever like a well built 400 but there are a bunch taking 3600lbs GN's into the 9's.

You will be in the 500 hp range and I would venture a guess a well built 200-4r will last you a long time.

studlybilly

Tin Fer, Imma look into that, not sure if I can find one, I can find TH400's for 150 bucks all day and get friction rebuild kits for 220 bucks with valve body components (possibly less). I'd love OD though.

studlybilly

So I spose the remaining questions are:

What modifications will I need to do if any to the stock cross member in order to bolt a Th400 in (if any)?

Will I be able to use a 10" Torque converter made for the Th400?

If it came off of a Chevy v8, the bellhousing should bolt onto my LT1 correct?

With this being a 94, do I have computer concerns or anything of that reason going to this Th400?

and lastly, Will the slip yolk work with the Th400 or will I have to adapt a Th400 slip yolk?

93LS1RX7

iTrader: (8)

If it is like the LS1 then yes you will have to reflash the PCM to a M6 setup. Otherwise the PCM will be looking for inputs from the 4L60e and you will have some issues.

studlybilly

Ya, my guess is the LT1 isnt to much in difference than the LS1, I'll call around to some local shops and see who can reflash it.

insaneclown

If I were you I would not move to a different tranny. I have a 92 camaro that for all intended purposes shat its tranny behind my 355hp motor. I was seriously looking at a built up TH350. But then I started looking at what it would take to convert. You need at least $100 in brackets/crossmembers and then you would need to throw at least another $100 at the speedo issue. And then you have to pay for a CORE of a TH350 or TH400. You are talking a very easy $300 additional on top of the stout rebuild... and THEN you are stuck WITHOUT OVERDRIVE!!

My uncle who owns a tranny shop told me that the 700s can be built just as strong as the 350s and 400s. Granted it might be a little more money but you should be able to make that up since you already own your core.

studlybilly

As of now I'm looking further into options for the 4l60e's, I've talked myself into giving the tranny a chance. I'm going to put an unbreakable sunbelt spindle in it, 5 pinion planetary's, corvette servo, master rebuild kit with red clutches and kolene steels, complete oil pump (of course), and transgo shift kit.