Transmission Woe's

[gearhead351]

hello all, I am new to this forum so I hope this is the correct area of which to inquire in.. I have a 1997 GMC K1500. Its a short box, single cab, 4 wheel drive, Vortec 350, 4L60E.

 

It has 123,000 miles on it and the truck is extremely clean.

 

Here is my issue, One day on a 50 mile venture out to a buddy's, The trans was shifting fine, I have ALL gears, including reverse. I started heading back, then it started shifting WAY hard. I knew it was going into fail safe mode, so line pressure was maxed out.

 

The problem is when it shifts into overdrive (I think), it doesnt fully engage. I can throttle the pedal and watch the rpms climb, but it only climbs a few hundred rpm, it doesnt rev like its in nuetral. A check engine light finally came on, I got a code that said either 4th gear is slipping, or the torque converter was slipping.

 

When I got home I dropped the pan and put a new filter, plus really good fluid. The bottom of the pan was pretty clean, barely any deposits on the bottom. I took it for a drive and it actually was good for about ten minutes then it started doing the slip deal in 4th.

 

I found another transmission to rebuild, so I dont have to have my truck torn apart to rebuild the one in it.

 

What should I check? Is this electrical? It isnt shifting hard anymore, so? not sure. I am a Ford guy so bear with me!

 

Thanks! matt

[KMGZ400]

exactly what happend to my old truck, the problem was my 4th gear clutch housing and the torqe converter was shot if i remember correctly

[gearhead351]

thats what I was suspecting . . well since Im gonna pull it out and replace it. . might as well put some performance parts too. . time to spend some dough!

[gearhead351]

ok guy's, I hope someone is very familiar with the 4l60e parts that make it last. . Im looking for a bit more performance, the truck always seemed sluggish off the line. total dog compared to my ford running 40's . . .

 

so I have a list here to hopefully last a long time, and perform much better. .

 

$35.95 - B&M shift improver kit

 

$216.75 - B&M Tork Master 2000 stall Converter, with lockup.

 

$44.95 - Jet Performance Billet 2nd gear servo

 

$74.95 - Jet Performance Billet 4th gear servo

 

$77.95 - Beast Sun Shell

 

$36.95 - TCI 0.490 Boost valve

 

$74.95 - TCI Front Pump

 

$177.95 - TCI Master Overhaul kit.

 

------------------------

 

With a Grand total of . . . $740.40

 

 

I would like some insight as to; will this perform much better? Last longer? Over Kill?

 

I am never going to be pushing ore than 350 HP in the truck . . so Let me know! THanks!

[Z'06]

I heartily recommend the Sonnax servos (both the 2nd and the 4th gear servos) after upgrading from the combination of the Vette servo and stock 4th servo. Firmer shifts, but not too firm for a daily driver as would be the Superior Fairbanks servos that are recommended in racing applications. I don't know how the Jet stacks up to stock/Vette/Sonnax/Superior though.

 

TransGo HD2 shift kit seems to be a consensus favorite on the performance-oriented truck forums. That and a TransGo hardened separator plate plus the TransGo .500 boost valve, along with Sonnax pinless accumulator pistons (to replace the GM ones that are now plastic) and new solenoids should take care of most valve body drop (i.e., next simplest after the servo swap) upgrades (although the HD2 kit comes with a few more items that you could only use in a complete transmission teardown).

 

Take a look at Circle D for modified Trailblazer (278mm) and modified 4.8L converters (300mm) torque converters., both of which provide higher stall speeds that still drive mostly like stock, which is great for daily driving.

 

None of the above requires a complete teardown of the transmission, like adding the Beast sun shell requires. If you go that far, you might look at replacing the 3-4 clutch pack, too. The sky's the limit on anything else you want to replace while you are in that far, like billet input/output shafts, etc.