Tranny and U joint questions
Thread Starter
Drifting
Joined: Nov 2001
Posts: 1,348
Likes: 25
From: STL Mo
Tranny and U joint questions
My 87 has me wondering if the tranny is on its way out or u joints When i put the car in drive I feel a pretty good thud when it goes into gear also when Im slowing down and the tranny is downshifting It just sounds too loud when shifting I feel and hear the gears. It doesnt seem to be slipping What should I be looking for, or is it in need for a service? Also what should I be looking for for u joints in need of replacment
Drifting
Joined: May 2004
Posts: 1,747
Likes: 1
From: Port McNicoll Ontario
I just replaced my u-joints on the passenger side. It's a lot cheaper than any tranny work.
As Bogus said, grab your shafts and try to move them with your hands. If there is play the u-joints should be replaced.
I also found that when they were shot I had a vibration when driving. It was more noticeable on the highway and when I was accelerating.
If you have a similar vibration I would assume the u-joints are your problem.
As Bogus said, grab your shafts and try to move them with your hands. If there is play the u-joints should be replaced.
I also found that when they were shot I had a vibration when driving. It was more noticeable on the highway and when I was accelerating.
If you have a similar vibration I would assume the u-joints are your problem.
Team Owner
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Originally Posted by bogus
I would check the ujoints first... they are easily tested... grab the driveshaft and if they move, they be done.
This is a good rule of thumb, but not the final answer. My joints were "bad" yet there was no perceptable movement when checking in this manner. IMHO, if the joints have more than 80K miles on them, replace em. On the other hand, during this winter's Project Overhaul I replaced, overhauled or inspected every component of the drivetrain (including tranny) except the diff. Most of the "clunk" has gone away. I have checked the backlash on the diff by rotating the driveshaft by hand with the E-Brake on and it feels a bit excessive. This is purely subjective since I have no idea what acceptable would feel like. I will say that when she's running on cruise control there are moments where the drivetrain sounds like it wants to break! I'll be replacing the diff soon........
I wonder if engine mounts are a soft spot for the C4's?
-JRC-
Drifting
Joined: May 1999
Posts: 1,478
Likes: 3
From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
I agree with JrRifleCoach. Sometimes you can't tell the u-joints are going bad until you pull them off. My mechanic talked me out of replacing the half-shaft u-joints saying they didn't look or feel bad. He is a real honest guy and will not sell you on work or parts you don't need. A few months later when I replaced the rear wheel bearings I pulled the half-shaft u-joints and discovered they were in need of replacing. On the car and tightened in the straps they seemed fine, but off the car with the needle bearing caps removed you could see that it was time for new ones. This was at approx. 75k miles.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: May 1999
Posts: 1,478
Likes: 3
From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
There are a few types of Spicer u-joints available for the C4. Greaseable (zerk fittings) and non-greaseable. The Spicer Brute Force non-greasable u-joints are supposed to be the very best. There are 2 types of Brute Force non-greaseable units available to fit the C4 half-shafts. The 5-800X version has aluminum end caps specifically for the C4's aluminum half-shafts. The other Spicer unit has steel caps and will work as well, but you should use antiseize on the caps if you use the steel capped version. I replaced mine with 5-800X which were readily available at a local large truck repair facility.