IROCZ28dan

I dont know if anyone will have an answer for me. I talked to a guy at pro-built about my 700 and their shift kit (trans-go with vette servos, boost valve, and accumulator to allow soft shifts at part throttle while firm ones at WOT). He said the shift kit works well with 88+ transmissions, only because of their upgraded valve body. he says the 86 and before valve bodies are different, and causes the working of the shift kit to be hit or miss, either it works well or it shifts goofy. he called 87 the bastard year. early 87s got 86 valve bodies. late 87s got 88+ valve bodies. my door sticker says 4/87 and i figure thats late in the production year, as new cars tend to come out in september. i dont have the ability right now to tear off my transmission pan, as the transmission isnt in the vehicle and so it makes it harder to work on. however, im anxious to know what kinda valve body i have. can someone give me a clue if they know?

also, my vin is 1G1FP21FXHN151651...the decoder is broken...but its my understanding that the last 6 numbers are the production number. but on here it says only 137,760 were produced. so wtf you know? can someone give me a hand?

88 350 tpi formula

iTrader: (9)

you need to get the numbers off the side of the trans. there located on the side just above the pan.



there is a casting mark on the side which would let you know however I think I would confuse you first. the best way is to get the numbers

IROCZ28dan

8663549 on the trans...whats that mean?

dont tell me the first 2 numbers mean 86 .

im hoping it doesnt mean 86 transmission, 63549th one produced.

88 350 tpi formula

iTrader: (9)

note 88 would just be "8"

IROCZ28dan

oh
definitely not where i got my number
mine was cast into the transmission...directly on the side...about 6-7 inches above the pan.

the number im looking for is on the trans pan? what will tell me if its an 88? just the number 8?

88 350 tpi formula

iTrader: (9)

it should be like 8ykmy00248949267a similar the first digit "8" this is the example my 88 manual shows (slightly differant than the 91 I posted but, still same digit shows year)

IROCZ28dan

so the number i got eithe a. says that i have an 88 valve body, because the first number is 8...or b. the number i got is null and void because its not where you specified. at the same time..you showed a 91 4l60e...whereas i have an 87 700r4...could the ID process have changed or no.

88 350 tpi formula

iTrader: (9)

no same thing the 88 just shows more information (it has some extra numbers after the trans type and build date.

IROCZ28dan

so i gotta look for that number by the pan...

whats the number i got?

also...im not looking for an 88 transmission, ive got an 87 one. i need to know if the internal is an 88 valve body like late model 87s got. would that mean it would have the 88 transmission ID?

88 350 tpi formula

iTrader: (9)

I just think you would be better off getting the number by the pan I will decode it for you. I say this because most of the autos are not original and assuming so is just going to lead you into trouble. I mean look how old your car is. the only 100% sure way is to pop the pan off but, you said it was too hard right now so the next best thing is to see when it was made. those numbers will show the day of the year and shift it was made. give you a better idea. so if it says it is a 86 then you know, if it says 92 then you know if it is an 87 well then it is a hit or miss still and you need to pull the pan.


but, like I said it may have a differant trans

IROCZ28dan

ill get back to you on tuesday then when i get to work on the car. im positive the transmission is all original.

firebirdjones

I just went through this with my 88 Iroc. I installed a B&M shift kit in mine a couple weeks ago. According to B&M the change to the 700R4 was made sometime in the 88 model year and I had to determine which one I had because it made a difference in the placement of the valve body *****.
My car is a very early model, made in September of 87, it has 50,000 original miles and still runs the original trans, I checked the numbers above the pan on the passenger side just as described and found that I did infact have an early 1988 trans that closely matched the build date of the car.
When I removed the valve body I was able to further confirm this by checking where all the ***** were in the valve body according to the diagrams I had and sure enough, they matched early 1988 diagrams, at some point for what ever reason GM changed a couple of the ball locations in the valve body in the 88 model year from what I have found. So I followed the instructions in the B&M shift kit for the mid 1988 and back model year. Everything worked perfectly with no problems. Just my experience with it. Hope that helps, Larry.

firebirdjones

Just to add, B&M did not specify when exactly in 88 the change happened, no dates etc...so in order to confirm exactly for me, I pulled the valve body, (had to anyway for the shift kit) and checked all the ball locations in the valve body, this confirmed for me that I had the early 88 valve body, since your car is an 87 I would say you have the early style, if in fact your trans is original. Hope this helps, Larry.

IROCZ28dan

the change didnt happen in mid 88...it happened in mid 87...the guy at probuilt automatic transmissons told me, and a chevy dealership confirmed it.


anyways...i searched high and low on the transmission, and there was no identification number besides the one i already posted.

however, on both sides of the transmission housing it said "8" really big, and on the passenger side just behind the bellhousing it said MD8. there was a tag on the driver side top behind the bellhousing, but it just looked like a piece of plastic, no writing of any sort. doesnt look like there had been either.

firebirdjones

I tend to disagree only because I just recently had mine apart and verified the older style via the check ball positions in the valve body, which were the same as the 87 and back transmissions yet my car is an early 88 with the original trans still in the car. Plus the fact that B&M states the change was made sometime in 88, my car was proof of this, being an early 88 and having the 87 and back check ball positions, so in my case the change had not accured yet when my car was manufactured. Anyway it does not matter, if your trans is original and in an 87 car I would think it is safe to say you have the older setup. Just my experience with this particular 88 F-body, only way to know for sure is to open yours up and compare the check ball positions, I have the diagrams I can scan and e-mail you if you like. Hope this helps, Larry.

Apeiron

The changed happened in 87. Look for the auxiliary valve body under the pan. Later models have it, earlier ones don't. Doesn't surprise me B&M is wrong.

firebirdjones

That is not the change I am talking about, I know all about the auxilary valve body, the change I am talking about is main valve body ball placement, that was also changed mid 88 model year, they moved the ***** to different holes sometime in the 88 model run, if I knew how to post pictures I would show you what I mean. It makes a difference on the shift kit which is what the original post was about if I am not mistaken so I wanted to throw this out there hoping it would help since I just went through this myself. Larry.

IROCZ28dan

nah. the shift kit i'm talking about is a trans-go not b&m...might be different somehow. ive never heard about anyone having problems with a trans-go. but the probuilt guy told me that ebcause of the way this thing is setup, pre 88 valve bodies may have difficulties shifting properly. im assuming because of the 1-2 accumulator, making soft part throttle shifts and hard WOT shifts...

he explained it to me specifically and i assume its because of the auxillary valve body.

firebirdjones

that is very possible, I guess if you are going to have probuilt do the trans, I would assume it will come with some kind of warranty so if it is not to your liking it can be fixed again? I know that does not sound good.
The B&M kit I just installed was pretty easy, on the 1-2 accumulator they give you spacers to install in place of the springs, (remove both springs) also there is a spring to remove in one of the valve body pistons, new pressure regulator spring, drill 3 holes in the valve body plate, and move some of the ***** around according to year of transmission. That was about it, real easy and I didn't have to do anything with the auxillary valve body. Anyway, this thing hits hard at part throttle and full throttle and I don't have that "flareup" shift problem that alot of people complain about, shifts firm everytime. I hope you can get something done to your trans that you like with minimal hassle. Larry.

IROCZ28dan

probuilt isnt building it. they just sell the kit. and for 10 more bucks than what summit sells only the trans-go kit for, its a steal.

im getting the trans-go shift kit...part# TRG-700 from summit
corvette servo and boost valve
and trans-go 1-2 accumulator allowing soft part throttle and firm WOT like i said.

its worth it, the probuilt site just says 88+, so i called and asked why. which is why i posted here.

firebirdjones

Oh I understand now, that would have me asking too as to why it is certain years, sounds strange, since the B&M I just bought is for all 82-93 700's that are non electronic, it comes with many pieces for all different years (applications) and good intructions as to how to verify what you have. Makes it real easy. The trans go kit has me puzzled too. Let me know what you find out. Larry.