Hopefully one of you can help me out here. I am in the process of changing my speedo gears. I needed to go with 15 tooth and 44 tooth speedo gears. My car (88 IROC) came from the factory with really high gears (2.73s I believe). From research I found that I needed to change the sleeve to accommodate the new 44 tooth driven gear. I got the new sleeve (part # 25512339) for the driven gear. All was going fine up until right after I installed the new drive gear and bolted the tailshaft back up. I then went to put in the new sleeve and found that the diameter of the new sleeve (where it seals against the tailshaft) is much smaller than the original sleeve. It doesn't come close to filling the hole where the sleeve goes in. Its just too small :/ All research I have done shows this is the right sleeve though, I am totally baffled!!! Since it is an 88, its a cable driven setup. The original (bigger) sleeve was plastic. The new one is aluminum and it looks exactly like other photos I've seem of the 25512339 sleeve, which is supposed to be the correct sleeve. Any ideas? Any help is greatly appreciated, I am at a total lose. Thanks in advance!

too small as in ... needs an o-ring? Or too small as in ... is about 1/2 the require diameter? The GM sleeve for the 700-R4/th350-C/th250-C 44 tooth driven gear was discontinued whenever I tried to get one, so I don't know what you ended up with. I have a few of the correct sleeve I bought from a trans. supply place. Lemme know if you need one.

Too Small as in "even with an o-ring it isn't gona fit right" lol I definetly ended up with the wrong part somehow. The original sleeve was just over 2 inches in diameter. The new one is just under 2 inches in diameter. I think I may have ended up with a sleeve to fit a TH400, which I have heard is slightly smaller in diameter. I don't know yet if the GM part number 25512339 that I have read about is just consistently listed wrong on sites & boards, or if they screwed up the packaging of the part.

I'll get it to work, and I'll post back with any updates.

Thanks for the offer about your extra sleeves. I'll let you know.

I have the aluminum sleeve that fits my 45 tooth driven gear, I assume 44 tooth would be the same. With the O-ring it is a PERFECT fit. If you want I still have the box with part number at home. I just bought this sleeve a month ago from a local Chevy dealer after an aftermarket plastic sleeve was too damn tight in the tranny tailshaft housing.

You can e-mail me or I can just post the number here after work. Let me know.

If you could post the part # that would be great - Thanks!

I think I found the right part # today though...I'll see and post the results when I get a chance to work on it again.

This is what I originally ordered based on info I consistently saw regarding this application:







I am still thinking this is the sleeve for a 400

Damn, I got a 25512339 myself and it fit perfect. Not to question your ability but are you sure you used a new GM O-Ring? Mine is loose without the O-Ring. You are using a 700R-4 Tranny, not a T-5? Just asking, never can be too sure.

It is a 700R4 and this part is definetly too small. They may have just packaged the wrong part in the right box. I believe the correct diameter should be 2.1 inches. This one is a little less than 2 inches in diameter. I was also told that the 400 sleeve (which this may be) looks almost identical to the aluminum ones for the 700, but they are smaller in diameter. I'll see what happens with the new parts.

Thanks

There is a sleeve for TH350.

There is a different sleeve for TH350-C, TH250-C, and 700-R4.

The o-ring groove is located differently.

How do I know? I used a TH350 sleeve in a 700-R4. It leaked and was "loose."

Not sure off the top of my head what you have. But it's not a 700-R4 sleeve. Might be TH400.

The correct one I installed doesn't leak.

-Matthew

I had the same problem of course my car was cable driven. I tried a TH400 sleeve and it was too small, probably what they sold you. I know if you search around this page you can find the correct VSS and cable driven GM part numbers or you could go to www.700r4.com/ they sell all the parts you need or use to.

THIS USE TO BE PART OF THIS SITES TECH ARTICALS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
http://www.eecis.udel.edu/~davis/z28...edo/sleeve.jpg
It should be once again.

Just to be clear, this is the correct offset housing for 43+ or so I forget but its what I used when I had problems finding the correct part. Funny because the dealer told me there was no such thing, found this that night after 2 hours of searching went back the next day gave them the part number, had it by 12 noon. It was in there warehouse all along. SOBLS

I've always heard it was 40+, not 43+.

Hopefully this is a simple question--I replaced my stock 2.73 gears with 3.23's and a zexel torsion posi. A couple of third gen guys told me i only have to replace one of the speedo gears to get my mph right again. What part # do i need to order? Any help woud be greatly appreciated. P.S. i have a 700 R4 4 speed.

It might be, it been a few years since I had to do this so my brain is quite a bit fuzzy. I do remember that some of the aftermarket units were hinkey and fit increments of 3 or somthing funny like that. The factory made 3 different sleves for 700R4's one I doubt anyone with a 3rdgen in mind would ever use, small (for big honking monster truck tires) middle (our cars and most GMs) and this one for low ratio axles (numericly high ratio).



iroczz89.

You need to use the tire diameter, drive gear tooth count and current driven gear to find out what setup you need. You will need a higher tooth count driven gear at the least, maybe another drive gear, its hard to say. If you add 1 tooth to the driven gear it slows the speed reading nearly 4mph. If I had to guess you will probably need a driven gear with 3 more teeth to be close to accurate.

Your 15 tooth drive gear is pn 8642620. The driven sleeve & gear assembly is pn 25522495.

BTW, the 25512339 sleeve fits M29, M33, & M38 trans, all TH350 derivatives, not a 700R4.

I disagree.

Gee whiz, I guess the current GM Electronic Parts Catalog is wrong then. Maybe you should call the General & tell him about it & all those customers I sold that exact part # to for their TH350s back in the 70's &80's.

Rick,

Is it possible the 700-R4 sleeve fits the TH350 tailhousing well enough to work, whereas the TH350 sleeve doesn't fit the 700-R4 tailhousing well enough? I've tried the latter, but not the former.

Possibly, I have the 25522495 in my car as we speak & no leaks.

I'm not saying your wrong, just that the 25512339 fits perfecto in my 700R-4. Hard to argue with it when it works.

Oh crap Mike we must be blind, we had to have been leaking massive amounts of clear transmission fluid for years


Actually Rick the 25512339 is a cable driven sleeve are you sure your not giving the number for VSS? Maybe the number you have is a new listing or somthing. I do know 25512339 fits only TH375 & 700R4's that is fact.

You gotta admit that the clear tranny fluid is pretty funny, Rick! :rockon:

Ricktpi, hell for all we know GM could have two part numbers for one part. I know that the smaller the tooth count the smaller the gears mainshaft. Does 25522495 list for a different tooth count other than 40+ teeth maybe, or could the sleeve come with a gear?

http://www.eecis.udel.edu/~davis/z28...p/misc/speedo/


More information from this page, quite usefull. Anyone know if this guy is still around these boards? This information did save my butt a couple years back I'd like to thank him in public. :hail: Mike Davis.

The 25522495 is a 44 tooth driven gear & plastic sleeve assembly for 700R4 transmissions & cable driven speedos. This info is right out of the current GM EPC. If you don't believe me check it out with your local GM dealer.

The difference is problably the Aluminum vs a Plastic sleeve. Good info Rick!

OK Problem solved!

First, I tend to agree with RickTPI that 25512339 is not made to fit the 700R4. #1 Because as you can see from my pics, I bought the 25512339 for my 700R4 and it just did not fit. #2 based on the diameter specs I got as required for the 700R4, it did not match. #3 Parts guy at local GM dealer said the 25512339 was for vehicles made back in the 70s (I forget the exact years he mensioned). The only way this could not be the case if they put the wrong part in my box (which had this listed as the part number).

Anyway, I scratched the idea of going with another GM part since I have gotten a ton of different "correct" part #s. From websites, to boards, to tech guys, to the GM part dept, all give different answers...not to menstion the GM parts are pricey. So I went and got myself a TCI part # 880023 from Summit (less then $10.00 - It was 9 dollars and a few cents versus GM LIST: $59.07 for the 25512339). TCI said it was for a 700 and there are NO variations in the required diameter of the hole in the tailshaft. They said they are all 2.1 inches, which is what I was measuring as being required. So I got it and it arrived today. Popped it in after work and it fit like a glove!

One other thing some might ask about one day that I discovered in my application (didn't see this mensioned anywhere else) is that the stock driven gear sits on a steal shaft, which supports it. The new driven gear eliminates the steal shaft, as the shaft is part of the gear itself. That may be due to the fact that I had such a small driven gear to start with (car came with 2.73s in the rear). I posted a coupe more pics below.

The solution part:


The original gear with the steal shaft:


The new driven gear:


Thanks to all for the offers of advise, help, etc... Glad this is now complete!

PS Based on my findings, the info on the sites below are just flat out wrong regarding the sleeve to use. They both say to use the 25512339 part #. That really threw me off (again, unless they packed the wrong part, AND the GM parts dealer is wrong as well).

http://www.chevytalk.com/tech/transm...edo_gears.html

http://www.transmissioncenter.net/SwapInformation.htm