what tranny are you runnin

[coreyd]

I have a 90 burb, 3/4 ton, 456 gears 37" tires with the 350 400 241 combo what are the rest runnin. I ask because i am thinking about changing it, at freeway speed 75 or so i am at 3100.

 

[JIMs70K25]

same combo in my 89, except 33s and 4.10 gears. 3000 at around 70mph.

 

[sandawgk5]

I currently have 700r4 with 3.08 and 31s and turn about 1800 at 75 .
I am going to 4.10s and 37s calculated I should be about 2700 in 3rd locked at 70. And as soon as I have the money 5.13s are goin in the 60/14FF.

Ira

 

[Thunder]

So are you thinking of overdrive?
Bascly you have 3 choices As far as transmissions go
1.4L60/700r4. Auto trans
Pros: Will bolt right in with drive shaft and crossmember? mods.
OD tranny better MPG, Low 1st gear,Fairly Easy swap.
Cons: Weak tranny. Espically in a 3/4 ton. Need to get a built one for your big tires and 3/4 tom running gear. Also need a very good tranny cooler.

2. Go manual with a NV 4500
Pros: Overdrive and a little stronger than a 4l60
Cons: It is the weakest of the manual trannys. Will require more modification. Clutch, cross member, driveline, ECT could get expensive unless you have a donor vehicle handy.

3 4l80E Auto trans
Pros: Great strong tranny. Will bolt in, (May require slight driveline mods.)
Cons: Need a $800 computer to run it.

Or you can get some kind of an aftermarket overdrive unit.

 

[Hossbaby50]

Any tranny you swap in other then an NV4500 manual or a 4L80E auto is a downgrade from a TH400. With 37's on a Burb I wouldn't even consider downgrading to a 700R4. It is a waste of good money.

I have had a number of 700R4s in my K5 and I am never going to pay for one again. If I had the money I would swap in a 4L80E. I don't have the money so I have a Th400 sitting in my garage waiting to be swapped in.

A 4L80E may have an $800 computer that you need but with a good 4L80E and the $800 computer you will end up spending less in the long run over a 700R4.

Harley

 

[coreyd]

I have been really thinking about the 4l80e, I guess i will start my search for one now, thanks.

 

[sweetk30]

find a 91 with a 4l80 in it and swap out the wire harness and plug in the stuff and be done with the swap. 4l80-e is basicly the same tranny as 400 buut over drive. i think its the same 1-2-3 gear ratios. i love my 4l80-e .

 

[Seventy4Blazer]

easier to get larger tires..... :Wink1:
Grant

 

[1985_K5_Silverado]

This calc can be a quick and handy way to fiddle around with tire size, gear ratios, etc:

http://www.csgnetwork.com/rearendgearcalc.html

 

[muddybuddy]

ive got a 1ton k5 that will be running 40's soon wth 700r4 and im debating bout either building up a 700r4 or 4L80e when my current tranny goes....im not sure what ill end up doing

 

[mini_mull]

Love my 4L80E. Can't even hear the motor over the road noise at 70. Go for it if you can afford it, it's the best option, IMO.