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Lets go round two on a Tranny....

Avery4jc

Avery4jc

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All right guys I've been searching for hours and haven't been too impressed with what I've found other than what eveyone keeps telling me, SM465 blah blah blah as if there are no other good transmissions on the planet. Well I can tell you right now that I won't be going SM465 so lets talk about some other options....

If you are all addicted to magazines like I am you may have picked up the latest issue of diesel world. They have an article in there about the new Allison Tranny backing up the new duramax diesel for GM. It's a new 6 speed with gears 5 and 6 both being od. Pretty cool stuff. Has anyone ever put an Allison into an old chevy like ours? Are there bell housing size issues?
My dad thought I was crazy because they are some of the best transmissions on the planet and would cost too much for me to do but with the new 6 speed coming out I thought I might be able to find someone with more money than brains who just has to have the latest and greatest out there in which case I might be able to get the "old" Allison 5 speed auto for not too much. Anyways that was one option I was dreaming about but wanted to get ya'lls opinions first....

The next option I was looking at was a TH400, I want to do a little more research on it but it seems to be a little more keep it simple stupid style. 3 gears but tuff as nails if built properly as I have seen from Branndon's burnouts and such. LMK what you think about that if you have any opinions...

Finally there is always the option of a newer verison of mine since I do drive on the street mostly and will be doing trips to Pismo fairly often in which case I drive for 80 miles, pull a few miles of 6% grades then drive the last 70 miles in which case it would be nice to have od. Something like a 4L80E I believe its called now.

I just wanted to get a fresh Transmission thread going and have some discussion on the ones listed above and of some that I'm sure I forgot.

I don't have a huge budget but to me some things are worth saving for and after this trip the Tranny will be one of them. I'm on a time span of about a month since school starts towards the end of August and I have to be able to drive this year. Senioritis is already coming over me, whoot whoot!

-Avery
 
The Turbo 350 transmission is not exactly a week transmission. I have had several over the years, which held up fine behind 300 HP. You should just take your truck to a good transmission shop, and have them rebuild yours with a Master kit. A good Master kit has all new steel bands, clutches, bearings, reverse band, and seals. Put this together with a shift kit, transmission cooler, and your Turbo 350 will handle any normal use without a wimper.

I would advise not to mess with these modifications some people are talking about. These people have the knowledge, tools, and money to get exstensive modifications done to their trucks, so it is real easy for them to say "yea, go ahead and do it"; plus, their trucks are probably not their DD's. If you are not that knowledgable, have minimum tools, and your truck is a daily driver, You are just asking for trouble, if you start exstensivly modifying it. I garauntee that modifying your truck will be a monster that feeds on itself. One modification will lead to another, and another, until it becomes a money pit, which rarely gets driven.
 
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for the amount u drive i think a 4L80E would be the best bet. it is basically a t-400 w/ overdrive. u would need a tranny controler to run it though. the alison imo would be pimp but i don't think u could do it nearly as cheap as a 4l60e.
 
I know an Allison would require a stand alone computer to control it, beyond that I have no idea how it would be done. I can say that I am very happy with my TCI 700r4 truckmaster/B&M 2400 Holeshot combo though.
 
Avery, It all depends on what you inted on doing with your tranmission. The TH350 is a very capable transmission if it is re-built by the right person. Granted, the TH400 is stronger but sometimes it is best to work with what you have. $$ And time occordingly.
The alison and the 4l80e are going to require stand alone computer systems to work. There is a manual valve body available for the 4l80e but it requires you to shift the transmission. (unless something new has come up) The alison, as beautifull as it is would take BoooKooo $$ to get going in our vehicles.
If I were in your shoes I would rebuild what you have, it simplifies things and if done right can give you years of enjoyment. With me personally as I am having transmission problems as well I am rebuilding my 700r4. A lot of people would think I am crazy but I like having my OD and my low first gear. I have also seen a lot of 700r4's as well as TH350's behind big blocks on the race track.
Strength of any part in your drive train comes down to how you drive. One of the biggest culpret's of breakage is shocking the drive train. I am an easy driver and don't do much rock crawling, burn outs, or soft to hard pack terrain changes. My vehicle spends the majority of its time exploring back woods and sand dunes. I hadly EVER shock my drive train, therefore the 700r4 with my 10 bolts will last me a long time.
I don't know what you have for gears but if your truck has big tires and factory gears it will be hard on your transmission. Look at the whole picture when you take this into consideration its all expensive! lol Anway, thats just my 02 and Im done babbling. Good luck my man.

~Brian
 
if you aren't going SM465 then just rebuild the tranny you have with a shift kit.
 
Ok guys I just woke up and read the replies, thanks for the input. There is some confusion though in the first few posts, I have a 700r4, not a th350. If I had a th350 I would just rebuild it.

I really do like having od but with the problems I've already had with the 7004r and then it finally puking its guts on me on the highway I really don't trust it even rebuilt seeing as I'm eventually going to get this thing off road. I was also reading and found that I believe it was 1987 and up the 700r4 tranny was built differently and held up better so some people were saying that it wasn't even worth using mine as a core to rebuild and if I want a 700r4 to get a newer one.

boz42: you mentioned the 4L80E and then the 4L60E, typo or are there two? Oh, and yeah the Allison would be pimp which is why I mentioned it. Plus I haven't found anyone who has one in a late model chevy like mine.

Something else I was considering in all this mess was my old plans for the summer. I wanted to get a d44 in the front and a 14b in the rear then save for new wheels and tires and have it all done before school started so that I could drive it. Now with all this mess going on my dad said that I might want to consider regearing my 10b axles and then dumping my time and money on tranny and possibly a 205 tc since I'll have it all gutted anyways.
I know you guys all swear by the 14b and I would love to do it but for the time being all I do is street and eventually sand which isn't too hard on drive train compared to rocks.
Or I was thinking that I could find a k20 to gut the tranny, tc, and axles out of. Do you think that would be a better idea? Then I would have a better core tranny to rebuild and when I had the tranny out being rebuilt I could rebuild the axles with a seal and bearing kit and pop them under before the tranny came back. Ok too much writing I'll sit back and listen to some opinions again. Thanks!

-Avery
 
I figured since your truck was a 1985, it still had a Turbo 350, with a carburetor. Those 700R4's do suck. This also means you have one of those computer controled carburetors too. The problem with this is your engine has an ECM, and the 700R4 probably has a speed sensor tied into it. Since you live in smog Nazi country, this presents a problem. Almost anything you do to your truck to change it may cause a problem with smog. A manual body Turbo transmission would be nice, but how does that square with your ECM, which needs a speed sensor tied into it.

My recomendation, since you live in smog Nazi country, is to sell that truck, and go buy a 1-ton or an older truck, if you want a truck with a tough drivetrain.
 
Avery4jc said:
Or I was thinking that I could find a k20 to gut the tranny, tc, and axles out of. Do you think that would be a better idea? Then I would have a better core tranny to rebuild and when I had the tranny out being rebuilt I could rebuild the axles with a seal and bearing kit and pop them under before the tranny came back. Ok too much writing I'll sit back and listen to some opinions again. Thanks!

-Avery
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I think this is your best bet if you can find a good deal on one in the time frame you're talking. As far as regearing the 10-bolts, you could find a set of 3/4-tons with the gears you want/need for the around the same price. Might as well beef up with your money spent. What gears are looking to go to? It might be hard to find a set with anything lower than 4:10's, but that wouldn't be a problem if you went to a 465. :wink1: Just razzing ya. If you really want to stick with an auto, then go that route, but if you're really wanting to build the truck for reliability off road, even if it is a ways away, then do the manual swap now. No point in spending money twice on the same thing.
 
Ok now I'm really going nuts on options. I think you are right fabjunkie about the axles but I think that was one reason I blew my 700r4 so I would need to do the axles before I ran w/ my new tranny. I was thinking about 4.56's

I really think that I need to find a k20 and go from there. I spoke with my friend from school (he's actually an old physics teacher, drives the bronco, I think I've spoken about him before) and he said that he personally likes the 700r4 and for what I do he was thinking that it would be my best bet. On bowtieoverdrive they sell 700r4's that are supposedly indestructable. I know not all of you like it but for the reasons that 1-ton brought up and more I might be better off rebuild my 700r4 with as much beef as possible.

I won't do too many serious off roading trips in this truck and being honest with myself the only thing this truck does and will do is drive around town, drive the highway taking me to school and ocassionaly driving the highway to play in the sand at pismo. None of which should blow a properly built 700r4 right?

One other factor we haven't thought about was the p.o....

there is no way of knowing what he did to this transmisison and I guarantee from what I know about him he didn't put any work into the tranny so were talking about a 21 year old bone stock tranny running 38.5's on 3.08's. I don't think I could expect it to hold up much longer than it did. How about 4.56's w/ the new axles and a properly built 700r4?

-Avery
 
With a tire that large and a 700R-4 I'd go 5.13...wouldn't even consider anything else. Anything much taller than that is just going to contribute to another tranny failure.

It's so easy to bolt up the big tires, but it's a lot more work and $$ to make the truck work correctly with them.

Rene
 
Ok, I'll be interested to hear everyone else's opinions on the subject over the next few days but from what I can gather from you all I should rebuild the 700r4 and get my new axles put in w/ some 5.13's.

I'm afraid 5.13's would be a little too low for me since I'm on the road though. I really like this site (http://www.4lo.com/calc/geartire.htm) and according to them I should run in the range of 4.56

What size tires did stock k10's come with, in the 28-30" range?

-Avery
 
38.5's, 700R-4, 5.13's, 65 mph = 2037 rpm

Ideal IMO, and a combo that pretty much ensures you're not going to bake another 700R-4.

Try this page: http://www.4lo.com/calc/geartable.htm

Multiply any of those 'rpm's' by 0.70 to get the final rpm's your truck will be doing.

Rene
 
Sounds good to me.

JP0863 lives in Clovis (a city right next to Fresno) and told me about a local tranny shop which he has used and trusts their work. I spoke with my old teacher this morning and he has a shop that would put most out of garage builders to shame. He said that if I want I can bring the truck over and he'll help me drop the tranny and then we can take it over to the tranny shop to be rebuilt.

I think I'm going to go that route. Now that the tranny problem planning is solved (at least on paper) I am going to hunt down some axles.

-Avery
 
Avery4jc said:
Sounds good to me.

JP0863 lives in Clovis (a city right next to Fresno) and told me about a local tranny shop which he has used and trusts their work. I spoke with my old teacher this morning and he has a shop that would put most out of garage builders to shame. He said that if I want I can bring the truck over and he'll help me drop the tranny and then we can take it over to the tranny shop to be rebuilt.

I think I'm going to go that route. Now that the tranny problem planning is solved (at least on paper) I am going to hunt down some axles.

-Avery
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IIRC, go look at Bowtie Overdrive again regarding rebuilding the first gen. 700. BTO won't take them as cores, defective design. My '85 700 is still out in the back yard, can't throw it in the trash.
 
IIRC, go look at Bowtie Overdrive again regarding rebuilding the first gen. 700. BTO won't take them as cores, defective design. My '85 700 is still out in the back yard, can't throw it in the trash.
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I remember when GM had a huge recall of the first few years of the Turbo 700R. It caused GM huge financial losses.

I read somewhere that the problem was a retaining clip, which locked a planetary gear in place to the mainshaft, failing, thus allowing the planetary gear to wobble around on the mainshaft, and eventually destruct.
 
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roadnotca said:
IIRC, go look at Bowtie Overdrive again regarding rebuilding the first gen. 700. BTO won't take them as cores, defective design. My '85 700 is still out in the back yard, can't throw it in the trash.
Click to expand...

Either way the fact of the matter is I need to rebuild a 700r4 to put into my truck, whether the core comes from my truck or from a junk yard it doesn't make a lick of difference to me.

I would love to go with something like the th400 but I don't know if I want to give up OD and my low first gear. Plus as mentioned before I'm setup to use a 700r4 with my TV cable. Where as a 700r4 has somewhat of a lifeline to the engine to shift the th400 is completley stand alone correct? If so and I decide to go that route to gain some durability and lose OD could I just pop it in and then all my adjustments would be with the modulator valve?

Thanks a ton for the help guys.

-Avery
 
Nope. Whereas 700 reads inputs from the one cable, TH350 & TH400 use vaccuum and throttle position. Thats why the 700 is so picky with the TV adjustment, the 350 & 400 are much more tolerant of misadjustment. For eg. a leaking modulator will tell you its leaking, but it won't destroy the trans. Neither will the throttle cable, and its really easy to notice.
I thought we all agreed that with our oversized tires, we couldn't use OD on anything but flat and downhill anyways.
Crawl (low first?), get the right R & P.
I'm not hardover against the 700, it just that all the others are better.:D
 
I'm still sticking by the fact that I am very happy with my TCI truckmaster/B&M Holeshot combo, I have 4.56's and 35's, and I drive about 40 miles round trip every weekday with it.
 
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