Tonyrodz's Tahoe Build Thread

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

OP
OP
Tonyrodz

Tonyrodz

Resident Resident
Joined
Feb 16, 2012
Posts
31,595
Reaction score
47,076
Location
Central Jersey
Maybe, maybe not...There's the boost valve and sleeve that can be swapped out with the transmission still in the vehicle...You'll need a small pair of interior/exterior snap ring pliers to do it but it's not difficult...A worn boost valve will cause the issues you're having as well...I always replace those pre-existing boost valve and sleeves with the Sonnax large ratio boost valve kit - it comes with a higher pressure spring for the PR valve and gives you about a 10% increase in line pressure at all throttle angles...Transgo's boost valve does the same thing...If this trans already has an upgraded boost valve then yes, more than likely you're dropping the transmission to figure out and fix the problem, but a pressure test will definitely help you narrow things down and give you some baseline data for your diagnosis...Having a bi-directional scan tool plugged in at the same time will also be very helpful.

Here's line pressure testing instructions.
You're looking for pressures at idle to be within the ranges shown on the chart for each gear shifter setting and immediate line rise up to around 150-175PSI or so at WOT.
View attachment 423896
Also I still don't have any trouble codes set. Would/should it set a cel?
 

NickTransmissions

Sin City
Supporting Member
Joined
Mar 9, 2023
Posts
1,088
Reaction score
2,613
Location
The transmission bench
Also I still don't have any trouble codes set. Would/should it set a cel?
Sometimes, but some times codes won't set...In the absence of DTCs, simply focus on the symptoms. A 3-4 clutch pack failure never sets a DTC, the software for the 4-speed units isn't as sophisticated as later model transmissions so it's not going to be aware of much in the way of gear ratio errors, at least not until 2006 when the input speed sensor was introduced. Even then you usually won't get codes for 3-4 failure. And you will only get a DTC if your electronic pressure control solenoid goes bad such that continuity is lost.

TLDR? Don't get married to DTCs...If they set, great but if not, focus on symptoms...
 

Snowbound

Jim
Joined
Nov 23, 2016
Posts
1,055
Reaction score
2,477
Location
Chicagoland (Lockport)
Still putting a beating on ole girl and breaking stuff I see. I think you just like working on it, at the very least posting about it.
7k replies and over 700 pages? Holy cow! Takes a lot of time trying to keep up with this thread. Every time I come on here I’m trying to catch up on my watched threads but it takes longer than the time I have so I haven’t had a chance to respond.
Glad to see everyone still engaged, giving great advise and sharing experiences. I’m still being dumb and working more than sleeping per usual but still kicking.
 
OP
OP
Tonyrodz

Tonyrodz

Resident Resident
Joined
Feb 16, 2012
Posts
31,595
Reaction score
47,076
Location
Central Jersey
Still putting a beating on ole girl and breaking stuff I see. I think you just like working on it, at the very least posting about it.
7k replies and over 700 pages? Holy cow! Takes a lot of time trying to keep up with this thread. Every time I come on here I’m trying to catch up on my watched threads but it takes longer than the time I have so I haven’t had a chance to respond.
Glad to see everyone still engaged, giving great advise and sharing experiences. I’m still being dumb and working more than sleeping per usual but still kicking.
Lol, I actually hate working on anything anymore. Getting too old--or lazy lol. Got myself a new toy.20240105_165637.jpg20240105_165627.jpg
It's a ferd lol.
Thinking about smashing the Hoe--that'll teach it for being a fussy beyotch all these years.
 

Forum statistics

Threads
132,301
Posts
1,865,646
Members
96,885
Latest member
BinOdhaib
Top