Burb Needs a New Transmission

[shiftpro]

Get a new wife and then you wont have the nice vs cost constraints to deal with.

Lose the wife and do whatever you want.

 

[idahovette]

Gonna cost a lot of money to lose the wife...........nay not have any left

 

[Rusty Nail]

My 700R4 has some quirks, but it still holding on, however one day I know I'll be in the same boat. I've thought about going to a TH350 cause I hear it's an easy swap. I don't wanna steel the OP's thread but I do want to ask @Rusty Nail when you went from the 700R4 to the TH350 did you notice much of a mileage change? I do spend sometime on the freeway and also like the low first in the 700R4, but to me reliability is most important.

Search me. The Previous Genius beat me to it - part of the reason I bought that truck was because 350/350 is the combo of choice. I rebuilt the modification Sir.
I would NOT have bought the Blazer with a 700r4
Cant truss it!

xc_hide_links_from_guests_guests_error_hide_media

It sure as hell doesnt scream at 55 lmao... Matter of fact we can line em up if you wanna hear it scream go on the green light.
You can see my dual exhaust real good back there - I bet.



I bought one (turbo350) obviously because in my experience they are inferior to a 700. Especially in my application.
BECAUSE I am never in stop and go traffic or making short trips in open loop. I dont quantify another transmission gear -sacrificing durability, longevity, strength, and dependability so I can pretend to save a nickel running 11 miles down the highway, one way to work, three days a week.
2400 included the previously mentioned 1300 rpm heavy duty th400 convertor, a new detent cable and two ujoints.

Ill build it tough and buy more gas, it's not for girls. I chose to eliminate the reason they break...so I can drive it like I want. which is mostly in 2nd gear. AT THE SELECTOR!
Third gear is for the highway..

 

[RecklessWOT]

You're the first to mention the gear ratio and then what happened? He wants to run 33" tires. Absolutely needs to gear down. You know how the 700 doesn't like to be lugged. Even with the lower first gear is too much strain on it, and nuclear temps will cook it. AND he want to tow... eesh. Gear down brother!

I ran a 700R4 with 33s ans 3.73s for years, towed with it and everything. It was gutless, needed shorter gears for sure (I have a set of 4.56s that I'm swapping in when I fix the engine) but it never burned up. Yeah it didn't like being lugged, but if I kept my foot in it the thing was fine. I also have an aftermarket B&M trans cooler and temp gauge, and I've never even really seen it get hot. When towing a car trailer through the mountains in nasty late August heat it got a little "warm" on me once, so I slowed back down to 75-80 or so and it was fine after that. I absolutely ******* HATE the 1-2 shift of the 700R4, but man oh man is overdrive nice...

 

[SirRobyn0]

Here's what I don't understand. Here this guy has a wife that WANTS to drive a square body and just because she doesn't want a stick you guys all suggesting to get rid of her?!?!?!

 

[bad_idea]

Get a new wife and then you wont have the nice vs cost constraints to deal with.

LOL. Nah, she's a keeper. I have 5 cars in my driveway that I play with. I wanted a square body suburban and talked her into it by telling her it's for her. She takes good care of me, I have nothing to complain about.

 

[bad_idea]

I will add a trans cooler and temp gauge.

When/if I go to 33s, then I will regear. It is currently on 31s - what was stock? No idea what gears are in the axles, just haven't gone that deep into it - yet. Baby steps. For now I just want to get the trans right. I want to make sure the trans I install is capable of handling my plans for the vehicle. Looks like a built 700r4 will get it done.

I'll look into bowtie overdrive. I'll ask around if there is a good shop that builds them locally. Thanks all.

 

[shiftpro]

I ran a 700R4 with 33s ans 3.73s for years, towed with it and everything. It was gutless, needed shorter gears for sure (I have a set of 4.56s that I'm swapping in when I fix the engine) but it never burned up. Yeah it didn't like being lugged, but if I kept my foot in it the thing was fine. I also have an aftermarket B&M trans cooler and temp gauge, and I've never even really seen it get hot. When towing a car trailer through the mountains in nasty late August heat it got a little "warm" on me once, so I slowed back down to 75-80 or so and it was fine after that. I absolutely ******* HATE the 1-2 shift of the 700R4, but man oh man is overdrive nice...

Well imo your an odd case, in a good way. Lesser men than you have roasted greater 700s than yours, with less effort than what you put your through.
Your experience in my experience, is way beyond what is to be expected.
I suggest you do your fellow truckers a favor and don't share this info... I'm thinking you have the opposite of a Wednesday lemon... whatever that would be called. Plus you probably have some magic (talent) with your foot, because for example old ladies can roast an auto faster than a 20 yr old.

I like to gear and drive a 700 like a 4 speed. I don't think of that final gear as an overdrive to drop revs on the highway, I look at it like 4th gear...
if that makes any sense. I want my truck to still pull in 4th (overdrive), including climbing.

I'd would like a 4l80 with a Gear Vender, low gears... really low gears!
My fav one ton combo with 35" tires and a 4L80 are 4.88s.

 

[RecklessWOT]

I like to gear and drive a 700 like a 4 speed. I don't think of that final gear as an overdrive to drop revs on the highway, I look at it like 4th gear...
if that makes any sense. I want my truck to still pull in 4th (overdrive), including climbing.

I'd would like a 4l80 with a Gear Vender, low gears... really low gears!
My fav one ton combo with 35" tires and a 4L80 are 4.88s.

That was my intention when I decided to go with the 4.56s. I'll still be able to drive on the highway in OD (though not at a friggin zillion MPH anymore like the way I prefer), 1st will become an extremely low gear, and the other two will actually be usable for real life

 

[gmbellew]

I will regear my burb someday - it is also 3.73, 700r4, 33s. it is manageable now, but I would like to at least get it back to the stock ratios with the bigger tires. I was leaning toward just going to 4.10 to keep RPM manageable at 75mph and hopefully help from unlocking the TC on long mild inclines and from downshifting on slightly bigger hills. 4.56 seems like it would limit the highway a little bit unless you run 35s...

 

[SirRobyn0]

That was my intention when I decided to go with the 4.56s. I'll still be able to drive on the highway in OD (though not at a friggin zillion MPH anymore like the way I prefer), 1st will become an extremely low gear, and the other two will actually be usable for real life

I don't really want to hijack his thread but are you currently running 4.56s? If so I need to ask you a few questions. Though I'm running a wider tire, mine are the factory 31" tall, which RPM wise is not that different from your 33s (mine would be about 200RPM higher than yours). My C20 is a factory 3.41 700R4 truck and it's just terrible with my 18 foot trailer. It's marginal with a light load but getting up around 5K of weigh (load and trailer weight combined) and it's terrible in the mountains, like going over the pass. Getting up to speed is ridiculously slow. I'm torn on 4.10s vs 4.56s. I've run the numbers and I can see how the ratios for 3rd and OD are a really great combination for highway towing w4.56s. I can see how the really low first gear could be great getting a load going as well. Do I have that about right, any other advantages or disadvantages you can see? But how is first gear when your not loaded, like around town? I use the truck to haul for the farm a lot but also drive it to the shop in the city which involves at least some traffic. Thanks.

 

[RecklessWOT]

I don't really want to hijack his thread but are you currently running 4.56s? If so I need to ask you a few questions. Though I'm running a wider tire, mine are the factory 31" tall, which RPM wise is not that different from your 33s (mine would be about 200RPM higher than yours). My C20 is a factory 3.41 700R4 truck and it's just terrible with my 18 foot trailer. It's marginal with a light load but getting up around 5K of weigh (load and trailer weight combined) and it's terrible in the mountains, like going over the pass. Getting up to speed is ridiculously slow. I'm torn on 4.10s vs 4.56s. I've run the numbers and I can see how the ratios for 3rd and OD are a really great combination for highway towing w4.56s. I can see how the really low first gear could be great getting a load going as well. Do I have that about right, any other advantages or disadvantages you can see? But how is first gear when your not loaded, like around town? I use the truck to haul for the farm a lot but also drive it to the shop in the city which involves at least some traffic. Thanks.

Currently the way the truck sits, the 4.56s are in a box on the passenger seat. It is hiding in the garage with what I hope is just a very blown headgasket lol. Before I put it back on the road I plan to swap the gears.

I had 31s on it for about 2 years (I believe it had like 225 70/15s on it from the factory or something stupid little, ditched those within a month of owning it) Mine had 3.73s and it was sluggish for sure, but within reason. With 31s I always felt I would be fine just switching to 4.10, but ever since I got the 33s it was just a dog. Sure 4.10s would be better but if I was already going in there to change them I wanted to make a real difference.

That's a tricky one. With 33's I went with 4.56s and feel it was a no brainer. With your 31s, they might feel a little too short, though not by a lot. I do drive fast on the highway for long distances and kept that in mind when choosing. I suppose the 4.10s and 31s combo could probably feel the way my stock baby tires and 3.73s felt on the highway, and even that was fine. The truck came from Colorado, for my maiden voyage I loaded it up with roughly 2000lbs inside the truck (tons of squat) and drove cross country from CO back to NH, through the Green mountains in VT and the White mountains in NH. It wasn't a powerhouse, but was a pleasant enough drive, I don't remember sitting there with my foot to the floor crawling up hills and swearing at it (heck, I never even had that problem really with 31s and 3.73s, though it was lacking on big grades for sure I can only imagine how frustrating 3.42s must feel lol). With that original gear combo it felt like a normal vehicle driving around town, shift points were reasonable and some power was there when needed in first. I didn't leave it way for very long and it was years so I don't remember too too clearly. I guess it all depends on your primary use for the truck. If it's mainly a working rig and you tow heavy loads with it a lot I don't think 4.56s would be at all out of line, though 4.10s could be fine for something you also like to just cruise around in sometimes too. I feel like even if it is a tad on the lower side and 1st gear is really short, you'll just be shifting to 2nd a little early, and on a 700r4 1st was always kind of intended to be a shorter gear anyway, hell it just might make the dead spot between 1st and 2nd feel like a real gear around town lol.

Doing the math, with my 33s I should have gone with 4.27s to put myself back to the way the truck felt with factory tires and gears, and I decided to go just a tad shorter, so we'll just have to see how it feels. Is this something you're determined to do right away, or is this one of those "man one day I really want to" sort of things? If I get around to it any time in the next couple of months (which is the plan), I'll let you know.

 

[yevgenievich]

I seem to like 3.73 with 33" tire for higher hwy speeds. If doing more towing 4.10 would be preferred. But that is with a big block and 4l80e

 

[SirRobyn0]

Currently the way the truck sits, the 4.56s are in a box on the passenger seat. It is hiding in the garage with what I hope is just a very blown headgasket lol. Before I put it back on the road I plan to swap the gears.

I had 31s on it for about 2 years (I believe it had like 225 70/15s on it from the factory or something stupid little, ditched those within a month of owning it) Mine had 3.73s and it was sluggish for sure, but within reason. With 31s I always felt I would be fine just switching to 4.10, but ever since I got the 33s it was just a dog. Sure 4.10s would be better but if I was already going in there to change them I wanted to make a real difference.

That's a tricky one. With 33's I went with 4.56s and feel it was a no brainer. With your 31s, they might feel a little too short, though not by a lot. I do drive fast on the highway for long distances and kept that in mind when choosing. I suppose the 4.10s and 31s combo could probably feel the way my stock baby tires and 3.73s felt on the highway, and even that was fine. The truck came from Colorado, for my maiden voyage I loaded it up with roughly 2000lbs inside the truck (tons of squat) and drove cross country from CO back to NH, through the Green mountains in VT and the White mountains in NH. It wasn't a powerhouse, but was a pleasant enough drive, I don't remember sitting there with my foot to the floor crawling up hills and swearing at it (heck, I never even had that problem really with 31s and 3.73s, though it was lacking on big grades for sure I can only imagine how frustrating 3.42s must feel lol). With that original gear combo it felt like a normal vehicle driving around town, shift points were reasonable and some power was there when needed in first. I didn't leave it way for very long and it was years so I don't remember too too clearly. I guess it all depends on your primary use for the truck. If it's mainly a working rig and you tow heavy loads with it a lot I don't think 4.56s would be at all out of line, though 4.10s could be fine for something you also like to just cruise around in sometimes too. I feel like even if it is a tad on the lower side and 1st gear is really short, you'll just be shifting to 2nd a little early, and on a 700r4 1st was always kind of intended to be a shorter gear anyway, hell it just might make the dead spot between 1st and 2nd feel like a real gear around town lol.

Doing the math, with my 33s I should have gone with 4.27s to put myself back to the way the truck felt with factory tires and gears, and I decided to go just a tad shorter, so we'll just have to see how it feels. Is this something you're determined to do right away, or is this one of those "man one day I really want to" sort of things? If I get around to it any time in the next couple of months (which is the plan), I'll let you know.

Well the answer is I'd like to do it tomorrow, but have already put it off for damn near a year. A couple of things are slowing me down. I currently have the 14B semi-float and have thought about swapping to FF, then deciding between 4.10 or 4.56. I guess I've delay it because I can't make up my damn mind!

I seem to like 3.73 with 33" tire for higher hwy speeds. If doing more towing 4.10 would be preferred. But that is with a big block and 4l80e

If I was running a 454 there would be less of a decision to make because I'd 4.10 it. I have a 99 class C motorhome with 454 & 4.10 and it pulls that along reasonably well. So I also like to keep in mind the future with my gears. Currently has a 305, it's a good running solid 305 and I'm not going to ditch it until it's warn out. But what will I do when it's done, likely I'll go with a 350, it's a straight forward swap the 454 requires a little more work. I think that the 305 and the 350 would do well with 4.56's for my purposes but until I get around to doing it, I like to get first hand opinions. In the 60's and early 70's they 4.56'ed 1 tons with the TH400 from the factory, I had a friend with a 72 like that. The only thing was you didn't drive it much over 60mph. With OD I'd think it would be a lot less limiting.

 

[SirRobyn0]

Nothing to see here was a double post.