Car slips out of gear

I have a 7.5 rearend with 3.73 gears at the moment
Oh, then you could definitely use an overdrive! I feel that the 2004R is a better choice than a 700R4 due to personal experience and because of the slightly different gear ratios, especially the transition or "gear spread" between first and second gear- the 700 spread is atrocious. On the flip side, custom 2004R planetary sets sometimes get used in th350s for better acceleration but it's not cheap.

The 200 will be ok with your current driveshaft length, the 700 isn't.

To properly rebuild a 700 or 4l60 you ABSOLUTELY MUST MODIFY OR REPLACE THE VALVE BODY. Period. The entire hydraulic circuit is a giant leak to begin with and the bodies are aluminum so they wear out as the assorted plungers and pistons do their thing.

G Bodies made before '83 need a frame rail extension for a 200/400/700 transmission crossmember.
 
Oh, then you could definitely use an overdrive! I feel that the 2004R is a better choice than a 700R4 due to personal experience and because of the slightly different gear ratios, especially the transition or "gear spread" between first and second gear- the 700 spread is atrocious. On the flip side, custom 2004R planetary sets sometimes get used in th350s for better acceleration but it's not cheap.

The 200 will be ok with your current driveshaft length, the 700 isn't.

To properly rebuild a 700 or 4l60 you ABSOLUTELY MUST MODIFY OR REPLACE THE VALVE BODY. Period. The entire hydraulic circuit is a giant leak to begin with and the bodies are aluminum so they wear out as the assorted plungers and pistons do their thing.

G Bodies made before '83 need a frame rail extension for a 200/400/700 transmission crossmember.
Which year for the 2004r do you recommend?
 
I think the '86-87 BRF versions are supposedly better, though I'm not a transmission expert, so for that question I refer you to a member by the name of Oldsofb. I don't know how to make his name a blue hyperlink so he's notified/ you could start a conversation though.
 
I think the '86-87 BRF versions are supposedly better, though I'm not a transmission expert, so for that question I refer you to a member by the name of Oldsofb. I don't know how to make his name a blue hyperlink so he's notified/ you could start a conversation though.
Thanks really appreciate the help!
 
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First off, I'm NO transmission guy.

If it were me, I would take it to a trans shop I trusted and have them diagnose the issue. After knowing what the issue is, then you can make an informed decision on rebuild or replace.

The BRF's came in 86-87 Turbo Buicks, and supposedly had a different valve body, servo, and torque convertor.

Hutch
 
Okay, I suggested the 4L60, not the 4L60E. The reason that I did suggest the non-electronic version is that you don't need a controller for it so you don't have to deal with the hassle of finding a place for the box and its wiring harness. it is actually closer in operating requirements to the 700R4 you mentioned in that it uses a TV cable assembly that, like the -R4 gets attached to the carb 9or throttle body if that is your bag) and which has to be set and adjusted in the same fashion as the one on the -R4. After, well a fast google search inundated me in how to vidoes. Most of them dealt with the E version but there were some others that discussed the non E. Were this my project, what i would be looking at is the flexplate, is the one I have going to be compatible or do I need to get one? Did whoever installed that 350 in the first place use an adapter plate or did they manage to do a direct bolt up with no adapters needed? The reason that I'd want to know about the adapter is that it comes with an extension that fits onto the boss on the converter in order to bridge the greater length/distance between the t-box and the block due to the adapter being there.

So what you may probably have to do is get the ride up on jack stands and slither under to see what's to be seen. If there is some kind of bolt pattern adapter in residence, you should be able to see it fairly quickly. Once its presence/absence is established, then you can go about collecting all the bits and pieces you may need to do the swap, depending on what you elect to acquire, and how deep your secret stash of project cash happens to be.

After thought, my 700R4 is in my van and it has 3.08's or somewhere around there. Lousy mileage in town but jack the bear on the interstate. My personal 1-2 is decently long, due I suspect to the fact that my -R4 came out of a C-10 and was built accordingly.



Nick
 
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Okay, I suggested the 4L60, not the 4L60E
You did, but the 4L60 has essentially no advantage whatsoever above the 700 because they're mechanically identical. A 4L60 (non-E) is a 700R4, they just changed the name and nothing else.

Like the other 2, the 4L60e is also trash until you put over $1k into it in parts alone at the very least, and that's before getting into using expensive mechanical diodes or the $1k Sonnax valve body. You can easily drop $5k on a 4L65E build if you're not careful, especially if you don't have a core.

Sadly, if you don't spend big bucks it often doesn't matter who rebuilds it because it's never going to last half as long as the factory unit did, which is expected to be at least 100k miles but often makes it just past 125k before failing. Unless you know someone who's extremely familiar with the valve bodies, knows the 200 minor changes in flow paths and parts over the course of 20+ years, and is willing to put together a unit comprised of parts spanning even longer since some good stuff is in the '04^ models. You'll want this case, that valve body design, the hardened shaft from these models, the later 5 pinion planetary, put this rebuild kit into that pump, etc.. Certain clutch materials are pointless and some are detrimental, different shift kits achieve the same result in different ways and not all mods are compatible.

Rebuilding these things correctly to handle any amount of power or to last 100k miles or more takes waayy more skill than most "rebuilders" I've had the displeasure of speaking to could even imagine. In my experience over 90% of them are nothing more than parts replacers.

The 200 has a cult following in the Turbo Buick world and therefore has infinite support for high power builds as well as testimonies to their durability even in stock form.

I'm no transmission expert myself, I've just grenaded a dozen 700s and researched the ever-loving snot out of the subject for years in an effort to stop doing that. Mostly because I only want to go through the pain once for my truck. It's taken me over a year to even find a builder I want to trust because I've been burned by half the shops around.

OP: Swap it to a manual if you truly want it to last- it'll cost the same in the end. If you do stick with an auto please don't even think of buying a cheap torque converter.
 
First off, I'm NO transmission guy.

If it were me, I would take it to a trans shop I trusted and have them diagnose the issue. After knowing what the issue is, then you can make an informed decision on rebuild or replace.

The BRF's came in 86-87 Turbo Buicks, and supposedly had a different valve body, servo, and torque convertor.

Hutch
Thanks man, I'm going to a shop tomorrow to make sure before I start buying a transmissions. The 2004R is kind of hard to get especially up here in Canada.
 
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First off, I'm NO transmission guy.

If it were me, I would take it to a trans shop I trusted and have them diagnose the issue. After knowing what the issue is, then you can make an informed decision on rebuild or replace.

The BRF's came in 86-87 Turbo Buicks, and supposedly had a different valve body, servo, and torque convertor.

Hutch

BRF and CZF 2004Rs both use D5 torque converters. BRFs I think used the biggest stock servos but have lower shift points to match 3.42 rear gears in the TRs. CZFs have higher shift points matched to the 3.73 rear gears in MCSSs.
 

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